64 results on '"Aarts, J."'
Search Results
2. Anisotropic magnetothermoelectric power of ferromagnetic thin films.
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Aarts, J., Anwar, M.S., and Lacoste, B.
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FERROMAGNETIC materials , *ENHANCED magnetoresistance , *CHROMIUM oxide , *MAGNETIC domain , *THERMOELECTRIC power - Abstract
In this article, we report the measurements of the magnetothermoelectric power (MTEP) in metallic ferromagnetic thin films of Ni 80 Fe 20 (Permalloy; Py), Co and CrO 2 at temperatures in the range of 100 K to 400 K. In 25 nm thick Py films and 50 nm thick Co films both the anisotropic magnetoresistance (AMR) and MTEP show a relative change in resistance and thermoelectric power (TEP) of the order of 0.2% when the magnetic field is reversed, and in both cases there is no significant change in AMR or MTEP after the saturation field has been reached. Surprisingly, both Py and Co films have opposite MTEP behaviour although both have the same sign for AMR and TEP. The data on half metallic ferromagnet CrO 2 films show a different picture. Films of thickness of 100 nm were grown on TiO 2 and on sapphire. The MTEP behavior at low fields shows peaks similar to the AMR in these films, with variations up to 1 % . With increasing field both the MR and the MTEP variations keep growing, with MTEP showing relative changes of 1.5% with the thermal gradient along the b -axis and even 20% with the gradient along the c -axis, with an intermediate value of 3% for the film on sapphire. It appears that the low-field effects are due to the magnetic domain state, and the high-field effects are intrinsic to the electronic structure of CrO 2 and intergarian tunnelling magnetoresistance that contributes to MTEP as tunnelling-MTEP. Our results will stimulate the research work in the field of spin dependent thermal transport in ferromagnetic materials to further develop spin-Caloritronics. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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3. Communication at an online infertility expert forum: provider responses to patients' emotional and informational cues.
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Aarts, J. W. M., van Oers, A. M., Faber, M. J., Cohlen, B. J., Nelen, W. L. D. M., Kremer, J. A. M., and van Dulmen, A. M.
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INFERTILITY , *INTERNET forums , *PATIENTS' attitudes , *PROMPTS (Psychology) , *THEMATIC analysis - Abstract
Online patient-provider communication has become increasingly popular in fertility care. However, it is not known to what extent patients express cues or concerns and how providers respond. In this study, we investigated cues and responses that occur in online patient-provider communication at an infertility-specific expert forum. We extracted 106 threads from the multidisciplinary expert forum of two Dutch IVF clinics. We performed the following analyses: (1) thematic analysis of patients' questions; and (2) rating patients' emotional and informational cues and subsequent professionals' responses using an adaptation of the validated Medical Interview Aural Rating Scale. Frequencies of themes, frequencies of cues and responses, and sequences (what cue is followed by what response) were extracted. Sixty-five infertile patients and 19 providers participated. The most common themes included medication and lifestyle. Patients gave more informational than emotional cues (106 versus 64). Responses to informational cues were mostly adequate (61%). The most common response to emotional cues was empathic acknowledgment (72%). Results indicate that an online expert forum could have a positive effect on patient outcomes, which should guide future research. Offering infertile patients an expert forum to communicate with providers can be a promising supplement to usual care in both providing information and addressing patients' concerns. [ABSTRACT FROM AUTHOR]
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- 2015
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4. Anomalous transport in half-metallic ferromagnetic CrO2.
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Anwar, M. S. and Aarts, J.
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FERROMAGNETIC materials , *CHROMIUM oxide , *MAGNETIC properties of thin films , *TITANIUM dioxide , *SAPPHIRES , *SUBSTRATES (Materials science) , *MAGNETORESISTANCE , *CARRIER density - Abstract
We have investigated the transport properties of CrO2 thin films deposited on TiO2 and sapphire substrates and find subtle differences with respect to earlier reports. The films are good metals down to low temperatures, with residual resistivities of the order of 6 μΩ cm for films deposited on TiO2 and two times higher for films on sapphire substrates. Magnetoresistance (MR) measurements in high fields show an as yet unobserved nonmonotonic behavior, which is particularly pronounced around the sign change that takes place from negative to positive at a temperature around 100 K. Moreover, both the ordinary and anomalous Hall coefficients show considerable changes around 100–150 K, suggesting a change in carrier density together with the onset of the influence of spin defects in this temperature window. At lower temperatures, the MR is a linear function of the applied field, which can be explained as intergrain tunneling MR. This interpretation is also suggested by the angular MR. Planar Hall effect measurements reveal that the CrO2 thin films are not in a single magnetic domain state even for films deposited on an isostructural TiO2 substrate. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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5. Doping and field effects on the lowest Kramers doublet splitting in La<f>1.6−x</f>Nd0.4Sr<f>x</f>CuO<f>4−δ</f> single crystal
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Sutjahja, I.M., Aarts, J., Nugroho, A.A., Diantoro, M., Tjia, M.O., Menovsky, A.A., and Franse, J.J.M.
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LANTHANUM compounds , *TEMPERATURE measurements , *CRYSTAL growth , *MAGNETIC fields - Abstract
We report the results of field-dependent specific-heat measurements on La
1.6−x Nd0.4Srx CuO4 (x=0 , 0.1, 0.2) single crystals grown by the travelling-solvent floating-zone method. Values for the electronic energy splitting (Δ ) of the lowest Kramers doublet of Nd3+ are deduced from these data by taking into account the lattice and electronic contributions and including the two-level Schottky function. The exchange-interaction-induced splitting of the lowest Kramers doublet of the Nd3+ ions observed previously in the absence of an external magnetic field is reconfirmed in this experiment. This value ofΔ is found to decrease with increasing Sr content (x ). Further, an increase ofΔ is shown to occur upon application of an external magnetic field aligned along the crystalc -axis. The analysis of these field-dependent data yields for theg -factor in the field direction the valuesg⊥=4.31 and 4.88 forx=0 andx=0.1 respectively. [Copyright &y& Elsevier]- Published
- 2003
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6. Collective and plastic vortex motion in superconductors at high flux densities.
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Troyanovski, A. M., Aarts, J., and Kes, P. H.
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VORTEX motion , *FLUX pinning , *POINT defects , *DYNAMICS - Abstract
Demonstrates that the imaging rates of vortices can be sufficiently high to resolve the dynamics in a high flux regime; Observations of vortex lattice in the presence of strongly pinning line defects; Observations of vortices in the presence of weak intrinsic point disorder.
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- 1999
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7. UK's National Programme for IT welcomes recommendation for a more sociotechnical approach to evaluation: a commentary on the Greenhalgh evaluation of the summary care record.
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de Lusignan S and Aarts J
- Published
- 2008
8. The A2Σ+-X2Π transition of SiCl revisited in the near ultraviolet.
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Aarts, J. F. M.
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ELECTRON emission , *EMISSION spectroscopy , *CATHODE rays , *ULTRAVIOLET spectra , *RADIOACTIVITY , *SPECTRUM analysis - Abstract
High-resolution emission spectra were obtained from a hollow cathode discharge in SiCl4/Ar mixtures. In the 360-450 nm region the emission of the [image omitted] transition of [image omitted] was detected and also the A2Σ+-X2Π transition of SiCl, previously analysed by Bredohl and co-workers. Some new bands of the A-X system of SiCl were identified and their rotational structure analysed. Improved molecular constants for the A2Σ+ state of SiCl have been obtained from the new data and those of Bredohl et al. For the emission of the [image omitted] transition of [image omitted] no vibrational or rotational structure could be resolved with a resolution of 10-3 nm. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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9. Observations on intensity oscillations in reflection high-energy electron diffraction during epitaxial growth of Si(001) and Ge(001).
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Aarts, J., Gerits, W. M., and Larsen, P. K.
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OSCILLATIONS , *REFLECTION high energy electron diffraction , *EPITAXY - Abstract
Intensity oscillations have been found in the specular beam of reflection high-energy electron diffraction patterns during growth of Si(001) and Ge(001) by molecular beam epitaxy. The reported results demonstrate the dependence of the amplitude and damping of the oscillations on different parameters such as substrate temperature, electron beam angle of incidence, and azimuth. [ABSTRACT FROM AUTHOR]
- Published
- 1986
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10. Disorder effects in epitaxial thin films of (La,Ca)MnO[sub 3].
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Aarts, J., Freisem, S., Hendrikx, R., and Zandbergen, H. W.
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THIN films , *EPITAXY - Abstract
We have investigated as-grown sputtered films of La[sub 0.7]Ca[sub 0.3]MnO[sub 3] in a thickness range between 5 and 200 nm on SrTiO[sub 3] substrates. The films are epitaxial, strained, and smooth. All films order magnetically around 175 K. Very thin films show full magnetization at low temperatures, but the temperature of the metal–insulator transition is appreciably lower than the magnetic ordering temperature. In thick films, the magnetization is much lower than expected. Both effects are probably related to structural disorder as found by transmission electron microscopy. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]
- Published
- 1998
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11. PMD116 - Is Big Data in Healthcare about Big Hope or Big Hype? Early Health Technology Assessment of Big Data Analytics in Healthcare.
- Author
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Bakker, LJ, Aarts, J, and Redekop, WK
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- 2016
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12. Inducing supercurrents in thin films of ferromagnetic CrO2.
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Anwar, M S and Aarts, J
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ELECTRIC displacement , *ELECTRIC properties of thin films , *FERROMAGNETIC materials , *TRANSITION metal oxides , *ELECTRIC contacts , *ENERGY bands , *MAGNETIZATION , *INTERFACES (Physical sciences) - Abstract
It is becoming gradually clear that it is possible to induce superconducting correlations in ferromagnets by generating so-called odd-frequency triplet Cooper pairs, which have two equal (rather than opposite) spins. Half-metallic ferromagnets (HMF) such as CrO2 are of special interest here since the presence of only a single spin band and no possibility for spin flip scattering can lead to very long lengths over which a supercurrent is induced. Early experiments with superconducting (S) contacts on CrO2 films found supercurrents over distances of up to a micrometer. The generation of triplet correlations is assumed to involve inhomogeneous magnetization or disordered magnetic moments in the ferromagnet or at the interface, and a major question still is how this is brought about in the S/CrO2 case. Here we report on experiments in which CrO2 thin films are grown on two different substrates, TiO2 and sapphire (single crystalline Al2O3). Using amorphous Mo70Ge30 superconducting contacts, we find supercurrents can flow in films grown on sapphire, but we have not been able yet to induce supercurrents in films grown on TiO2. We discuss this in terms of the differences in film morphology and the magnetic anisotropy for both film systems. We also show that the characteristic behavior of the clean S/HMF interface is a jump at the superconducting transition temperature of the resistance of the device to larger values. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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13. Computerized order entry: the authors respond.
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Aarts J and Koppel R
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- 2009
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14. OP07.04: Prediction of vesicouterine adhesions by transvaginal sonographic sliding sign technique.
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van Keizerswaard, J., Min, N., Visser, R., Burger, N., Rake, J., Aarts, J., Van den Bosch, T., Leonardi, M., Huirne, J.F., and de Leeuw, R.A.
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LAPAROSCOPIC surgery , *ABDOMINAL wall , *PELVIC pain , *BLADDER , *CHRONIC pain , *GYNECOLOGIC surgery - Abstract
This article, published in the journal "Ultrasound in Obstetrics & Gynecology," discusses the use of transvaginal sonographic (TVS) sliding bladder sign as a diagnostic tool for predicting vesicouterine adhesions. The study conducted at Amsterdam UMC included patients scheduled for gynecologic laparoscopic surgery for a benign disorder. The results showed that the absence of sliding bladder on TVS had a high positive predictive value for any adhesions and a high sensitivity for severe adhesions. The presence of sliding bladder had a high negative predictive value for severe adhesions and a high specificity for any adhesions. The study concludes that the sliding bladder sign using TVS is a reliable tool for predicting vesicouterine adhesions and recommends its routine use in preoperative planning. [Extracted from the article]
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- 2024
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15. Formation of a mixed ordered termination on the surface of LaAlO3(001).
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van der Torren, A. J. H., van der Molen, S. J., and Aarts, J.
- Abstract
We have investigated the surface termination of LaAlO3(001) at elevated temperatures by low-energy electron microscopy. The terminating layer can be LaO or A1O2. The LaO surface shows a √5 × √5 R26 reconstruction which can be used as a signature for the LaO termination, while the AlO2 termination is unreconstructed. We find that heating of as-delivered substrates in vacuum or heating substrates which were previously annealed in air or oxygen can lead to a reconstructed surface as observed in diffraction. However, the real-space image shows that the reconstructed areas only cover about one-third of the surface and that the termination is actually an ordered mixture of the reconstructed LaO and the unreconstructed AlO2 terminations. This conclusion is supported by data from atomic force microscopy. We also demonstrate how the disordered mixture of both terminations changes to large LaO islands in the middle of the AlO2 terraces upon heating. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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16. MEDUCATE trial: effectiveness of an intensive EDUCATional intervention for IT-mediated MEDication management in the outpatient clinic -- study protocol for a cluster randomized controlled trial.
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van Stiphout, F., Zwart-van Rijkom, J. E. F., Aarts, J. E. C. M., Koffijberg, H., Klarenbeek-deJonge, E., Krulder, M., Roes, K. C. B., Egberts, A. C. G., and ter Braak, E. W. M. T.
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INFORMATION technology , *MEDICATION therapy management , *RESEARCH protocols , *PATIENT safety , *PHYSICIANS - Abstract
Background: Using information technology for medication management is an opportunity to help physicians to improve the quality of their documentation and communication and ultimately to improve patient care and patient safety. Physician education is necessary to take full advantage of information technology systems. In this trial, we seek to determine the effectiveness of an intensive educational intervention compared with the standard approach in improving information technology-mediated medication management and in reducing potential adverse drug events in the outpatient clinic. Methods/Design: We are conducting a multicenter, cluster randomized controlled trial. The participants are specialists and residents working in the outpatient clinic of internal medicine, cardiology, pulmonology, geriatrics, gastroenterology and rheumatology. The intensive educational intervention is composed of a small-group session and e-learning. The primary outcome is discrepancies between registered medication (by physicians) and actually used medication (by patients). The key secondary outcomes are potential adverse events caused by missed drug-drug interactions. The primary and key secondary endpoints are being assessed shortly after the educational intervention is completed. Sample size will be calculated to ensure sufficient power. A sample size of 40 physicians per group and 20 patients per physician will ensure a power of >90%, which means we will need a total of 80 physicians and 1,600 patients. Discussion: We performed an exploratory trial wherein we tested the recruitment process, e-learning, time schedule, and methods for data collection, data management and data analysis. Accordingly, we refined the processes and content: the recruitment strategy was intensified, extra measures were taken to facilitate smooth conductance of the e-learning and parts were made optional. First versions of the procedures for data collection were determined. Data entry and analysis was further standardized by using the G-standard database in the telephone questionnaire. Trial registration: ISRCTN registry: ISRCTN50890124. Registered 10 June 2013. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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17. Direct real space observation of magneto-electronic inhomogeneity in ultra-thin film La0.5Sr0.5CoO3−δ on SrTiO3(001).
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Kelly, S., Galli, F., Aarts, J., Bose, Shameek, Sharma, M., and Leighton, C.
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THIN films , *LANTHANUM compounds , *MAGNETIC properties of metals , *ELECTRIC properties of metals , *NEUTRON scattering - Abstract
Recent magnetotransport and neutron scattering measurements implicate interfacial magneto-electronic phase separation as the origin of the degradation in transport and magnetism in ultra-thin film La1− x Sr x CoO3 on SrTiO3(001). Here, using low temperature scanning tunneling microscopy and spectroscopy the first direct, real space observation of this nanoscopic electronic inhomogeneity is provided. Films of thickness 12.4 nm (32 unit cells) are found to exhibit spatially uniform conductance, in stark contrast to 4.7 nm (12 unit cell) films that display rich variations in conductance, and thus local density of states. The electronic heterogeneity occurs across a hierarchy of length scales (5–50 nm), with complex correlations with both topography and applied magnetic fields. These results thus provide a direct observation of magneto-electronic inhomogeneity in SrTiO3(001)/La0.5Sr0.5CoO3 at thicknesses below 6–7 nm, in good agreement with less direct techniques. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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18. The surface structure of SrTiO3 at high temperatures under influence of oxygen.
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Hesselberth, M. B. S., van der Molen, S. J., and Aarts, J.
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SURFACE structure , *SURFACE properties , *OXYGEN , *HIGH temperatures , *ELECTRON microscopy , *VACUUM technology - Abstract
We use low energy electron microscopy to investigate the structure of the SrTiO3 (001) surface at elevated temperatures and different oxygen pressures. Upon varying the temperature between 500 °C and 900 °C in oxygen pressures ranging from 10-9 millibar to 10-4 millibar, two surface transitions are found to be present. The lower temperature (1 × 1) → (2 × 1) transition that is known to occur in ultrahigh vacuum can be reversed by increasing the oxygen pressure. At higher temperatures, we observe a (2 × 1) → disordered (1 × 1) transition which is irreversible in the experimental parameter range. The observations are expected to have a strong bearing on the growth of interface structures. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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19. Large electric-field effects on the resistance of La0.67Ca0.33MnO3 microstructures.
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Beekman, C., Komissarov, I., and Aarts, J.
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MICROSTRUCTURE , *FREE electron theory of metals , *ELECTRIC insulators & insulation , *MICROMECHANICS , *THIN films - Abstract
We investigate electric-field effects in thin film microbridges of La0.67Ca0.33MnO3 with the focus on the regime of metal-insulator transition. A mechanically milled SrTiO3 substrate is used as a backgate dielectric. Inside the metal-insulator transition we find a strong unipolar field-induced reduction in resistance, as well as a suppression of the nonlinear features in the I-V curves we observed earlier. We associate the observed effects with a phase separated state in which metallic regions coexist with short range correlated polaron regions. When the glassy polaron phase has fully developed and closes off the microbridge, the field effects disappear leaving the strongly nonlinear behavior of the transport current unaltered. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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20. Nonlinear mesoscopic transport in a strongly cooperative electron system: The La0.67Ca0.33MnO3 microbridge.
- Author
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Beekman, C., Zaanen, J., and Aarts, J.
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MESOSCOPIC phenomena (Physics) , *ELECTRON transport , *FREE electron theory of metals , *ENERGY-band theory of solids , *MAGNETIC fields , *FIELD theory (Physics) - Abstract
We investigate the electrical transport in mesoscopic structures of La0.7Ca0.3MnO3 in the regime of the metal-insulator transition by fabricating microbridges from strained and unstrained thin films. We measure current-voltage characteristics as function of temperature and in high magnetic fields. For strained films we find nonlinear effects in the steep part of the transition characterized by a differential resistance with a strong peak around zero applied current, and saturation at higher currents after a resistance drop of up to 60%. We propose that this nonlinear behavior is associated with the melting of the insulating state by injecting charge carriers, signaling the occurrence of an intervening phase that involves the formation of short-range polaron correlations. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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21. Effect of the variation of the exchange energy on the superconducting critical temperature of S/F/S trilayers.
- Author
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Kushnir, V. N., Prischepa, S. L., Aarts, J., Bell, C., Cirillo, C., and Attanasio, C.
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SUPERCONDUCTORS , *FERROMAGNETIC materials , *ALLOYS , *NIOBIUM , *MAGNETISM , *INHOMOGENEOUS materials , *F region - Abstract
The effect of the exchange energy variation in weakly ferromagnetic alloys on the superconducting resistive transition of superconductor/ferromagnet/superconductor (S/F/S) trilayers is studied. Critical temperature, T, and resistive transitions versus the F-layer thickness, d, have been analyzed in Nb/CuNi/Nb and Nb/PdNi/Nb trilayers. We show that T( d) dependence is sensitive to magnetic inhomogeneities in the F-layer for values of d corresponding to thickness range where the π-superconducting state is established. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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22. Gate-tuned anomalous Hall effect driven by Rashba splitting in intermixed LaAlO3/GdTiO3/SrTiO3.
- Author
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Lebedev, N., Stehno, M., Rana, A., Reith, P., Gauquelin, N., Verbeeck, J., Hilgenkamp, H., Brinkman, A., and Aarts, J.
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FERROMAGNETISM , *OXIDES , *MAGNETIC ions , *DENSITY , *HETEROSTRUCTURES - Abstract
The Anomalous Hall Effect (AHE) is an important quantity in determining the properties and understanding the behaviour of the two-dimensional electron system forming at the interface of SrTiO3-based oxide heterostructures. The occurrence of AHE is often interpreted as a signature of ferromagnetism, but it is becoming more and more clear that also paramagnets may contribute to AHE. We studied the influence of magnetic ions by measuring intermixed LaAlO3/GdTiO3/SrTiO3 at temperatures below 10 K. We find that, as function of gate voltage, the system undergoes a Lifshitz transition while at the same time an onset of AHE is observed. However, we do not observe clear signs of ferromagnetism. We argue the AHE to be due to the change in Rashba spin-orbit coupling at the Lifshitz transition and conclude that also paramagnetic moments which are easily polarizable at low temperatures and high magnetic fields lead to the presence of AHE, which needs to be taken into account when extracting carrier densities and mobilities. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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23. Magnetic properties of Sm-Co thin films grown on MgO(100) deposited from a single alloy target.
- Author
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Verhagen, T. G. A., Boltje, D. B., van Ruitenbeek, J. M., and Aarts, J.
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THIN films , *EPITAXIAL layers , *SPUTTER deposition , *RUTHERFORD backscattering spectrometry , *X-ray diffraction , *COERCIVE fields (Electronics) - Abstract
We have grown epitaxial Sm-Co thin films by sputter deposition from a single alloy target with a nominal SmCo5 composition on Cr(100)-buffered MgO(100) single-crystal substrates. By varying the Ar gas pressure, we can change the composition of the film from a SmCo5-like to a Sm2Co7- like phase. The composition, crystal structure, morphology, and magnetic properties of these films have been determined using Rutherford Backscattering, X-ray diffraction, and magnetization measurements. We find that we can grow films with, at room temperature, coercive fields as high as 3.3 T, but with a remanent magnetization which is lower than can be expected from the texturing. This appears to be due to the Sm content of the films, which is higher than expected from the content of the target, even at the lowest possible sputtering pressures. Moreover, we find relatively large variations of film properties using targets of nominally the same composition. At low temperatures, the coercive fields increase, as expected for these hard magnets, but in the magnetization, we observe a strong background signal from the paramagnetic impurities in the MgO substrates. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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24. Enhancing the charge ordering temperature in thin films of Pr0.5Ca0.5MnO3 by strain.
- Author
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Yang, Z. Q., Zhang, Y. Q., Aarts, J., Wu, M.-Y., and Zandbergen, H. W.
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THIN films , *MANGANITE , *PEROVSKITE , *ELECTRON microscopy , *MAGNETORESISTANCE , *STRAIN theory (Chemistry) , *ELECTRON diffraction - Abstract
We report the effects of biaxial strain on the charge ordering temperature Tco of the mixed-valent manganite perovskite oxide Pr0.5Ca0.5MnO3. Thin films were grown on SrTiO3, which has a 1.3% larger in-plane lattice parameter. Other substrates were used for comparison. Transport measurements combined with data from electron microscopy show that Tco is considerably enhanced. At thicknesses of the order of 10 nm, where the films are fully strained, Tco is above 320 K, more than 70 K above the bulk value of 250 K, while around 50 nm, where relaxation has set in, the enhancement is around 40 K. The bulk value is only reached at a thickness of about 150 nm. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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25. Use of threshold electron and fluorescence coincidence techniques to probe the decay dynamics of the valence states of CF+4, SiF+4, SiCl+4, and GeCl+4.
- Author
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Smith, D. M., Tuckett, R. P., Yoxall, K. R., Codling, K., Hatherly, P. A., Aarts, J. F. M., and Stankiewicz, M.
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PHOTOELECTRONS , *PHOTOIONIZATION , *FLUORESCENCE - Abstract
Threshold photoelectron–photoion coincidence (TPEPICO), photoion–fluorescence coincidence (PIFCO), and threshold photoelectron–fluorescence coincidence (TPEFCO) spectroscopies have been used to measure, state selectively, the decay pathways of all the valence states of four gas-phase tetrahedral ion CF+4, SiF+4, SiCl+4, and GeCl+4 in the range 11–26 eV. Vacuum UV radiation from a synchrotron source dispersed by a 5 m normal-incidence McPherson monochromator ionizes the parent molecule, and electrons and ions are detected by threshold electron analysis and time-of-flight mass spectrometry, respectively. Undispersed fluorescence from the interaction region can also be detected, allowing the three different types of coincidence experiment to be performed. The optimum resolution of the monochromator is matched to that of the threshold analyzer, and this work improves on preliminary results using a 1 m Seya monochromator [Chem. Phys. 174, 441 and 453 (1993)] where the resolution of the spectra was limited by that of the optical source. TPEPICO spectra are recorded continuously as a function of photon energy, allowing both threshold photoelectron spectra and yields of all the fragment ions to be obtained. Kinetic energy releases can also be measured at fixed photon energies with good time resolution. PIFCO and TPEFCO spectra are recorded at fixed photon energies. The former experiment can yield the fate of the lower electronic state of the parent ion to which fluorescence occurs.The latter experiment yields the lifetime of the fluorescing state; with sufficient resolution of the photoionizing radiation, the lifetime is specific to one vibrational level of the emitting electronic state. For CF+4 and SiF+4 work has concentrated on the third and fourth excited states, C 2T2 and D 2A1, of which only the C state of SiF+4 does not decay radiatively. Vibrationally state-selected fluorescence quantum yields and lifetimes have been measured for... [ABSTRACT FROM AUTHOR]
- Published
- 1994
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26. Defect-induced charge-order melting in thin films of Pr0.5Ca0.5MnO3.
- Author
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Zhang, Y. Q., Zhu, Y. L., Zhang, Z. D., and Aarts, J.
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THIN films , *EPITAXY , *CRYSTALLIZATION , *TEMPERATURE , *MAGNETICS , *PHYSICS - Abstract
We have investigated the relation between defect structure and charge order melting in thin films of epitaxial Pr0.5Ca0.5MnO3 (PCMO), grown under strain on SrTiO3. We compared the behavior of an 80 nm film grown in one deposition step at 840 °C with the behavior of a film grown in two steps. In the two-step case, a thin PCMO layer of 10 nm was deposited at 120 °C, followed by 70 nm deposited at 840 °C. The increase of the growth temperature leads to complete crystallization of the first layer and the lattice constants of the two-step grown film indicate that tensile strain is still present. On the other hand, a magnetic field of only 5 T is required to melt the charge-order state in the two-step grown film, which is a much lower than the value for the normally grown film. This appears to be connected to a larger amount of threading dislocations present in the first (recrystallized) layer. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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27. Effects of training physicians in electronic prescribing in the outpatient setting on clinical, learning and behavioural outcomes: a cluster randomized trial.
- Author
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van Stiphout, F., Zwart‐ van Rijkom, J. E. F., Versmissen, J., Koffijberg, H., Aarts, J. E. C. M., van der Sijs, I. H., van Gelder, T., de Man, R. A., Roes, C. B., Egberts, A. C. G., and ter Braak, E. W. M. T.
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OUTPATIENT medical care , *CLINICAL trials , *PHYSICIAN training , *MEDICATION abuse , *DRUG interactions - Abstract
Aims: Electronic prescribing systems may improve medication safety, but only when used appropriately. The effects of task analysis‐based training on clinical, learning and behavioural outcomes were evaluated in the outpatient setting, compared with the usual educational approach. Methods: This was a multicentre, cluster randomized trial [EDUCATional intervention for IT‐mediated MEDication management (MEDUCATE trial)], with physicians as the unit of analysis. It took place in the outpatient clinics of two academic hospitals. Participants comprised specialists and residents (specialty trainees, in the UK) and their patients. Training took the form of a small‐group session and an e‐learning. The primary outcome was the proportion of medication discrepancies per physician, measured as discrepancies between medications registered by physicians in the electronic prescribing system and those reported by patients. Clinical consequences were estimated by the proportion of patients per physician with at least one missed drug–drug interaction with the potential for causing adverse drug events. A questionnaire assessed physicians' knowledge and skills. Results: Among 124 participating physicians, primary outcome data for 115 (93%) were available. A total of 1094 patients were included. A mean of 48% of registered medications per physician were discrepant with the medications that their patients reported in both groups (P = 0.14). Due to registration omissions, a mean of 4% of patients per physician had one or more missed drug–drug interactions with the potential to cause a clinically relevant adverse drug event in the intervention group, and 7% in controls (P = 0.11). The percentages of correct answers on the knowledge and skills test were higher in the intervention group (57%) compared with controls (51%; P = 0.01). Conclusion: The training equipped outpatient physicians with the knowledge and skills for appropriate use of electronic prescribing systems, but had no effect on medication discrepancies. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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- View/download PDF
28. Mitigating target degradation in sputtering manganite thin films.
- Author
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Dildar, I.M., Boltje, D.B., Hesselberth, M.B.S., Beekman, C., and Aarts, J.
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MANGANITE , *SPUTTERING (Physics) , *THIN films , *ELECTRIC conductivity , *EPITAXY - Abstract
In this paper, we address the issue of aging of oxide sputtering targets, using the example of La 0.7 Ca 0.3 MnO 3 (LCMO), a material which is quite sensitive to the amount of oxygen. After prolonged use we find that the morphology of the films becomes poor: holes appear, the size of the steps between terraces becomes larger, the roughness increases, and electrical conductance in the metallic state at temperatures below the metal-insulator transition becomes smaller. We have performed experiments on reactive sputtering with water vapor in order to reverse their degradation. We discuss the growth and properties of films of LCMO on flat SrTiO 3 substrates before and after the target treatment. We study both the morphological and structural changes in these films as well as the transport properties. The results indicate that a correct concentration of oxygen in the targets is important, and that a deficiency can be compensated by the water treatment, thus increasing the usable life time of targets. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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29. Critical Voltage Of A Mesoscopic Superconductor Between Normal Electrodes.
- Author
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Keizer, R. S., Flokstra, M. G., Aarts, J., and Klapwijk, T. M.
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ELECTRIC potential , *ELECTRODES , *SUPERCONDUCTIVITY , *MESOSCOPIC phenomena (Physics) , *TRANSPORT properties of metal , *ELECTRIC resistors , *QUASIPARTICLES , *PHASE transitions - Abstract
We investigate the steady state transport properties of a mesoscopic superconducting wire between two normal metallic reservoirs by numerically solving the Usadel equation, going beyond the linear approach. From the calculation of the current-voltage characteristics we find a breakdown of the superconducting state which is characterized by a voltage rather than by a current; in other words, the system cannot be trivially treated as two resistors modelling the normal to supercurrent conversion, with a superconducting element characterized by its depairing current in between. Rather, the change in the longitudinal mode of the quasiparticle distribution function f (fL) triggers the breakdown, which can be considered as a first order phase transition. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2006
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30. Triplet generation and upper critical field in superconducting spin valves based on CrO2.
- Author
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Voltan, S., Singh, A., and Aarts, J.
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CHROMIUM oxide , *SPIN valves , *CRITICAL temperature - Abstract
It has been recently reported that a superconducting triplet spin valve (TSV) based on the half-metallic CrO2 can show "colossal" variations of the critical temperature, up to more than 1 K. This can be achieved when the magnetic noncollinearity between the mixer (F1) and the drainage ferromagnetic layer (F) is maximized. In this work we investigate further such TSV devices looking at two aspects: first, we present the dependence of the TSV effect on the thickness of the mixer layer; second, we look at the perpendicular upper critical field Hc2⊥ as a function of the temperature. The thickness dependence, which is nonmonotonic as expected, represents a further proof that the effect is due to the generation of equal-spin triplet Cooper pairs, while what we observe for the Hc2⊥ versus T curves is an interesting and peculiar behavior: there is a clear deviation from the universal linear dependence and the average slope is suppressed much more than what can be described with the formalism used for conventional proximized structures. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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31. OPTION(5) versus OPTION(12) instruments to appreciate the extent to which healthcare providers involve patients in decision-making.
- Author
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Stubenrouch, Fabienne E., Pieterse, Arwen H., Falkenberg, Rijan, Santema, T. Katrien B., Stiggelbout, Anne M., van der Weijden, Trudy, Aarts, J. Annemijn W.M., and Ubbink, Dirk T.
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PATIENT decision making , *MEDICAL care , *CANCER patients , *VASCULAR surgery , *COMPARATIVE studies , *DECISION making , *RESEARCH methodology , *MEDICAL cooperation , *PHYSICIAN-patient relations , *PSYCHOMETRICS , *RESEARCH , *PATIENT participation , *EVALUATION research , *RESEARCH bias , *CROSS-sectional method , *PATIENT-centered care ,HEALTH of patients ,RESEARCH evaluation - Abstract
Objective: The 12-item "observing patient involvement" (OPTION(12))-instrument is commonly used to assess the extent to which healthcare providers involve patients in health-related decision-making. The five-item version (OPTION(5)) claims to be a more efficient measure. In this study we compared the Dutch versions of the OPTION-instruments in terms of inter-rater agreement and correlation in outpatient doctor-patient consultations in various settings, to learn if we can safely switch to the shorter OPTION(5)-instrument.Methods: Two raters coded 60 audiotaped vascular surgery and oncology patient consultations using OPTION(12) and OPTION(5). Unweighted Cohen's kappa was used to compute inter-rater agreement on item-level. The association between the total scores of the two OPTION-instruments was investigated using Pearson's correlation coefficient (r) and a Bland & Altman plot.Results: After fine-tuning the OPTION-manuals, inter-rater agreement for OPTION(12) and OPTION(5) was good to excellent (kappa range 0.69-0.85 and 0.63-0.72, respectively). Mean total scores were 23.7 (OPTION(12); SD=7.8) and 39.3 (OPTION(5); SD=12.7). Correlation between the total scores was high (r=0.71; p=0.01). OPTION(5) scored systematically higher with a wider range than OPTION(12).Conclusion: Both OPTION-instruments had a good inter-rater agreement and correlated well. OPTION(5) seems to differentiate better between various levels of patient involvement.Practical Implication: The OPTION(5)-instrument is recommended for clinical application. [ABSTRACT FROM AUTHOR]- Published
- 2016
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32. Mesoscopic transport in thin films of La0.67Sr0.33MnO3.
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Dildar, I.M., Boltje, D.B., Hesselberth, M.B.S., and Aarts, J.
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THIN film deposition , *TRANSPORT properties of metal , *MANGANESE compounds , *ELECTRIC properties of metals , *HIGH temperature metallurgy - Abstract
We investigate thin films of La 0.7 Sr 0.3 MnO 3 grown on SrTiO 3 in which bridges of 100 μm long and 1 μm or 300 nm wide (distance between voltage contacts was 25 μm) were defined lithographically. In bridges of 1 μm, we find the current–voltage characteristics to be perfectly linear (ohmic) over the full temperature range between 400 K and 10 K. Strong non-linearities however are observed for a 300 nm wide bridge in the temperature regime below the transition temperature. The non-linearities are present even when applying a high magnetic field of 9 T. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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33. MEDUCATE trial: effectiveness of an intensive EDUCATional intervention for IT-mediated MEDication management in the outpatient clinic - study protocol for a cluster randomized controlled trial.
- Author
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van Stiphout, F, Zwart-van Rijkom, J E F, Aarts, J E C M, Koffijberg, H, Klarenbeek-deJonge, E, Krulder, M, Roes, K C B, Egberts, A C G, and Ter Braak, E W M T
- Abstract
Background: Using information technology for medication management is an opportunity to help physicians to improve the quality of their documentation and communication and ultimately to improve patient care and patient safety. Physician education is necessary to take full advantage of information technology systems. In this trial, we seek to determine the effectiveness of an intensive educational intervention compared with the standard approach in improving information technology-mediated medication management and in reducing potential adverse drug events in the outpatient clinic.Methods/design: We are conducting a multicenter, cluster randomized controlled trial. The participants are specialists and residents working in the outpatient clinic of internal medicine, cardiology, pulmonology, geriatrics, gastroenterology and rheumatology. The intensive educational intervention is composed of a small-group session and e-learning. The primary outcome is discrepancies between registered medication (by physicians) and actually used medication (by patients). The key secondary outcomes are potential adverse events caused by missed drug-drug interactions. The primary and key secondary endpoints are being assessed shortly after the educational intervention is completed. Sample size will be calculated to ensure sufficient power. A sample size of 40 physicians per group and 20 patients per physician will ensure a power of >90 %, which means we will need a total of 80 physicians and 1,600 patients.Discussion: We performed an exploratory trial wherein we tested the recruitment process, e-learning, time schedule, and methods for data collection, data management and data analysis. Accordingly, we refined the processes and content: the recruitment strategy was intensified, extra measures were taken to facilitate smooth conductance of the e-learning and parts were made optional. First versions of the procedures for data collection were determined. Data entry and analysis was further standardized by using the G-standard database in the telephone questionnaire.Trial Registration: ISRCTN registry: ISRCTN50890124 . Registered 10 June 2013. [ABSTRACT FROM AUTHOR]- Published
- 2015
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34. Task analysis of information technology-mediated medication management in outpatient care.
- Author
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Stiphout, F., Zwart‐van Rijkom, J. E. F., Maggio, L. A., Aarts, J. E. C. M., Bates, D. W., Gelder, T., Jansen, P. A. F., Schraagen, J. M. C., Egberts, A. C. G., and Braak, E. W. M. T.
- Subjects
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OUTPATIENT medical care , *MEDICATION therapy management , *MEDICAL schools , *MEDICAL education , *MEDICAL students - Abstract
Aims Educating physicians in the procedural as well as cognitive skills of information technology (IT)-mediated medication management could be one of the missing links for the improvement of patient safety. We aimed to compose a framework of tasks that need to be addressed to optimize medication management in outpatient care. Methods Formal task analysis: decomposition of a complex task into a set of subtasks. First, we obtained a general description of the medication management process from exploratory interviews. Secondly, we interviewed experts in-depth to further define tasks and subtasks. Setting: Outpatient care in different fields of medicine in six teaching and academic medical centres in the Netherlands and the United States. Participants: 20 experts. Tasks were divided up into procedural, cognitive and macrocognitive tasks and categorized into the three components of dynamic decision making. Results The medication management process consists of three components: (i) reviewing the medication situation; (ii) composing a treatment plan; and (iii) accomplishing and communicating a treatment and surveillance plan. Subtasks include multiple cognitive tasks such as composing a list of current medications and evaluating the reliability of sources, and procedural tasks such as documenting current medication. The identified macrocognitive tasks were: planning, integration of IT in workflow, managing uncertainties and responsibilities, and problem detection. Conclusions All identified procedural, cognitive and macrocognitive skills should be included when designing education for IT-mediated medication management. The resulting framework supports the design of educational interventions to improve IT-mediated medication management in outpatient care. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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35. Growing LaAlO3/SrTiO3 interfaces by sputter deposition.
- Author
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Dildar, I. M., Neklyudova, M., Xu, Q., Zandbergen, H. W., Harkema, S., Boltje, D., and Aarts, J.
- Subjects
- *
SPUTTER deposition , *THIN films , *PEROVSKITE , *PULSED laser deposition , *INTERFACES (Physical sciences) - Abstract
Sputter deposition of oxide materials in a high-pressure oxygen atmosphere is a well-known technique to produce thin films of perovskite oxides in particular. Also interfaces can be fabricated, which we demonstrated recently by growing LaAlO3 on SrTiO3 substrates and showing that the interface showed the same high degree of epitaxy and atomic order as is made by pulsed laser deposition. However, the high pressure sputtering of oxides is not trivial and number of parameters are needed to be optimized for epitaxial growth. Here we elaborate on the earlier work to show that only a relatively small parameter window exists with respect to oxygen pressure, growth temperature, radiofrequency power supply and target to substrate distance. In particular the sensitivity to oxygen pressure makes it more difficult to vary the oxygen stoichiometry at the interface, yielding it insulating rather than conducting. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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- View/download PDF
36. Detecting Rashba fields at the interface between Co and Si oxide by ferromagnetic resonance.
- Author
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Verhagen, T. G. A., Leermakers, I., van Ruitenbeek, J. M., and Aarts, J.
- Subjects
- *
FORCED vibration (Mechanics) , *FERROMAGNETIC resonance , *FERROMAGNETISM , *MAGNETIC resonance , *RASHBA effect - Abstract
We report ferromagnetic resonance (FMR) experiments on thin magnetic Co layers either sandwiched symmetrically between Cu and Pt, or sandwiched asymmetrically between a Cu or Pt layer on one side and a SiOx substrate on the other. In the symmetric samples, we find well-known behavior, namely, the FMR linewidth Δ Hpp is significantly larger for the case of Pt than for the case of Cu. This is due to the larger spin scattering in the Pt layer. However, for the asymmetric Co/Cu bilayers, the linewidth is much larger than for the symmetric Cu/Co/Cu trilayers and not much different from the linewidth of Co/Pt bilayers. We argue this to be due to the Rashba effect at the SiOx/Co interface, which gives rise to effective magnetic fields interacting with the electron spins in the Co layer and which can be measured without reverting to transport measurements. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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37. The effect of magnetic field on the intrinsic detection efficiency of superconducting single-photon detectors.
- Author
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Renema, J. J., Rengelink, R. J., Komen, I., Wang, Q., Gaudio, R., op't Hoog, K. P. M., Zhou, Z., Sahin, D., Fiore, A., Kes, P., Aarts, J., van Exter, M. P., de Dood, M. J. A., and Driessen, E. F. C.
- Subjects
- *
SINGLE photon generation , *MAGNETIC fields , *SUPERCONDUCTORS , *QUASIPARTICLES , *SPONTANEOUS magnetization - Abstract
We experimentally investigate the effect of a magnetic field on photon detection in superconducting single-photon detectors (SSPDs). At low fields, the effect of a magnetic field is through the direct modification of the quasiparticle density of states of the superconductor, and magnetic field and bias current are interchangeable, as is expected for homogeneous dirty-limit superconductors. At the field where a first vortex enters the detector, the effect of the magnetic field is reduced, up until the point where the critical current of the detector starts to be determined by flux flow. From this field on, increasing the magnetic field does not alter the detection of photons anymore, whereas it does still change the rate of dark counts. This result points at an intrinsic difference in dark and photon counts, and also shows that no enhancement of the intrinsic detection efficiency of a straight SSPD wire is achievable in a magnetic field. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
38. The effect of magnetic field on the intrinsic detection efficiency of superconducting single-photon detectors.
- Author
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Renema, J. J., Rengelink, R. J., Komen, I., Wang, Q., Gaudio, R., op 't Hoog, K. P. M., Zhou, Z., Sahin, D., Fiore, A., Kes, P., Aarts, J., van Exter, M. P., de Dood, M. J. A., and Driessen, E. F. C.
- Subjects
- *
MAGNETIC fields , *SUPERCONDUCTORS , *PHOTON detectors , *CRITICAL currents , *FLUX flow - Abstract
We experimentally investigate the effect of a magnetic field on photon detection in superconducting single-photon detectors (SSPDs). At low fields, the effect of a magnetic field is through the direct modification of the quasiparticle density of states of the superconductor, and magnetic field and bias current are interchangeable, as is expected for homogeneous dirty-limit superconductors. At the field where a first vortex enters the detector, the effect of the magnetic field is reduced, up until the point where the critical current of the detector starts to be determined by flux flow. From this field on, increasing the magnetic field does not alter the detection of photons anymore, whereas it does still change the rate of dark counts. This result points at an intrinsic difference in dark and photon counts, and also shows that no enhancement of the intrinsic detection efficiency of a straight SSPD wire is achievable in a magnetic field. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
39. Measurement of the spatial extent of inverse proximity in a Py/Nb/Py superconducting trilayer using low-energy muon-spin rotation.
- Author
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Flokstra, M. G., Ray, S. J., Lister, S. J., Aarts, J., Luetkens, H., Prokscha, T., Suter, A., Morenzoni, E., and Lee, S. L.
- Subjects
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SUPERCONDUCTORS , *MAGNETIC flux density , *FERROMAGNETIC materials , *NIOBIUM , *TRANSITION temperature , *MAGNETIZATION , *COOPER pair - Abstract
Muon-spin rotation has been used to observe directly the spatial variation of the magnetic flux density near the ferromagnetic-superconducting interface in a permalloy-niobium trilayer. Above the superconducting transition temperature Tc the profile of the induced magnetic flux density within the niobium layer has been determined. Below Tc there is a significant reduction of the induced flux density, predominantly near the ferromagnetic-superconducting interfaces. We are uniquely able to determine the magnitude and spatial variation of this reduction in induced magnetization due to the presence of the Cooper pairs, yielding the magnitude and length scale associated with this phenomenon. Both are inconsistent with a simple Meissner screening and indicate the existence of another mechanism, the influence of which is localized within the vicinity of the ferromagnetic interface. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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40. Interface-Induced Room-Temperature Ferromagnetism in Hydrogenated Epitaxial Graphene.
- Author
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Giesbers, A. J. M., Uhlířová, K., Konečný, M., Peters, E. C., Burghard, M., Aarts, J., and Flipse, C. F. J.
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FERROMAGNETISM , *MAGNETISM , *PARTICLES (Nuclear physics) , *ELECTRON configuration , *EPITAXY - Abstract
We show ferromagnetic properties of hydrogen-functionalized epitaxial graphene on SiC. Ferromagnetism in such a material is not directly evident as it is inherently composed of only nonmagnetic constituents. Our results nevertheless show strong ferromagnetism with a saturation of 0.9μB/hexagon projected area, which cannot be explained by simple magnetic impurities. The ferromagnetism is unique to hydrogenated epitaxial graphene on SiC, where interactions with the interfacial buffer layer play a crucial role. We argue that the origin of the observed ferromagnetism is governed by electron correlation effects of the narrow Si dangling bond states in the buffer layer exchange coupled to localized states in the hydrogenated graphene layer. This forms a quasi-three-dimensional ferromagnet with a Curie temperature higher than 300 K. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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- View/download PDF
41. Giant Magnetic Susceptibility of Gold Nanorods Detected by Magnetic Alignment.
- Author
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van Rhee, P. G., Zijlstra, P., Verhagen, T. G. A., Aarts, J., Katsnelson, M. I., Maan, J. C., Orrit, M., and Christianen, P. C. M.
- Subjects
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MAGNETIC susceptibility , *GOLD nanoparticles , *NANORODS , *SINGLE crystals , *MAGNETIC anisotropy , *SQUID magnetometers - Abstract
We have determined the magnetic properties of single-crystalline Au nanorods in solution using an optically detected magnetic alignment technique. The rods exhibit a large anisotropy in the magnetic volume susceptibility (ΔχV). ΔχV increases with decreasing rod size and increasing aspect ratio and corresponds to an average volume susceptibility (χV), which is drastically enhanced relative to bulk Au. This high value of χV is confirmed by SQUID magnetometry and is temperature independent (between 5 and 300 K). Given this peculiar size, shape, and temperature dependence, we speculate that the enhanced χV is the result of orbital magnetism due to mesoscopic electron trajectories within the nanorods. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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- View/download PDF
42. Mechanical Control of Electroresistive Switching.
- Author
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Kim, Yunseok, Kelly, Simon J., Morozovska, Anna, Rahani, Ehsan Kabiri, Strelcov, Evgheni, Eliseev, Eugene, Jesse, Stephen, Biegalski, Michael D., Balke, Nina, Benedek, Nicole, Strukov, Dmitri, Aarts, J., Hwang, Inrok, Oh, Sungtaek, Choi, Jin Sik, Choi, Taekjib, Park, Bae Ho, Shenoy, Vivek B., Maksymovych, Peter, and Kalinin, Sergei V.
- Subjects
- *
ELECTRIC resistance , *METAL-insulator transitions , *FERROELECTRIC materials , *PHASE transitions , *ELECTRIC fields , *PIEZOELECTRIC materials - Abstract
Hysteretic metal–insulatortransitions (MIT) mediated byionic dynamics or ferroic phase transitions underpin emergent applicationsfor nonvolatile memories and logic devices. The vast majority of applicationsand studies have explored the MIT coupled to the electric field ortemperarture. Here, we argue that MIT coupled to ionic dynamics shouldbe controlled by mechanical stimuli, the behavior we refer to as thepiezochemical effect. We verify this effect experimentally and demonstratethat it allows both studying materials physics and enabling noveldata storage technologies with mechanical writing and current-basedreadout. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
43. New directions in point-contact spectroscopy based on scanning tunneling microscopy techniques (Review Article).
- Author
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Tartaglini, E., Verhagen, T. G. A., Galli, F., Trouwborst, M. L., Müller, R., Shiota, T., Aarts, J., and van Ruitenbeek, J. M.
- Subjects
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SCANNING tunneling microscopy , *MOLECULAR probes , *ELECTRON scattering , *PHYSICS experiments , *ATOMS , *GOLD , *METALLIC surfaces - Abstract
Igor Yanson showed 38 yr ago for the first time a point-contact measurement where he probed the energy resolved spectroscopy of the electronic scattering inside the metal. Since this first measurement, the point contact spectroscopy (PCS) technique improved enormously. The application of the scanning probe microscopy (SPM) techniques in the late 1980 s allowed achieving contacts with a diameter of a single atom. With the introduction of the mechanically controlled break junction technique, even spectroscopy on freely suspended chains of atoms could be performed. In this paper, we briefly review the current developments of PCS and show recent experiments in advanced scanning PCS based on SPM techniques. We describe some results obtained with both needle-anvil type of point contacts and scanning tunneling microscopy (STM). We also show our first attempt to lift up with a STM a chain of single gold atoms from a Au(110) surface. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
44. Multiple order parameter configurations in superconductor/ferromagnet multilayers.
- Author
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Kushnir, V. N., Prischepa, S. L., Cirillo, C., Vecchione, A., Attanasio, C., Kupriyanov, M. Yu., and Aarts, J.
- Subjects
- *
SUPERCONDUCTORS , *FERROMAGNETISM , *FERROMAGNETIC materials , *MAGNETIC fields , *TRANSITION temperature - Abstract
The coupling of two superconductors (S) through a ferromagnet (F) can lead to either a zero- or a π -phase difference between the superconducting banks. Most research in this area is performed on trilayer S/F/S film structures, in which two-order parameter configurations are possible. Increasing the number of layers and junctions leads to a larger number of possible configurations with, in principle, different properties such as the superconducting transition temperature Tc. Here we study the behavior of a series of mullilayers made of superconducting Nb and ferromagnetic Pd81Ni19. We find that for the individual layer thicknesses used, the transition width ΔTc increases with increasing number of bilayers in the multilayer, in a well-defined manner. That the broadening is not simply due to increased disorder in the larger stacks, it is shown from x-ray diffraction, which finds very sharp interfaces for all samples; and from the effect of the magnetic field on the transition, which shows a considerable sharpening. We can make a connection with the various order parameter configurations using a matrix formulation of quasiclassical theory based on the Usadel equations and show that these different configurations take part in the Josephson networks, which are building up in the transition to the superconducting. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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- View/download PDF
45. X-ray scattering study of interfacial roughness in Nb/PdNi multilayers
- Author
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Vecchione, A., Fittipaldi, R., Cirillo, C., Hesselberth, M., Aarts, J., Prischepa, S.L., Kushnir, V.N., Kupriyanov, M.Yu., and Attanasio, C.
- Subjects
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X-ray scattering , *SURFACE roughness , *NIOBIUM compounds , *LEAD alloys , *FERROMAGNETISM , *SUPERCONDUCTIVITY , *MULTILAYERED thin films , *THICKNESS measurement , *SIMULATION methods & models - Abstract
Abstract: Specular and diffuse X-ray scattering are used to study interfacial roughness in Nb/Pd0.81Ni0.19 multilayers deposited by dc UHV sputtering. The data are analyzed to extract information about the correlated behavior of interface roughness in both the lateral and vertical directions. X-ray reflectivity is treated quantitatively by computer-aided simulation and modelling in order to extract values also for the layers thickness. From the analysis of the diffusive spectra of the reflectivity maps the roughness correlation has been evaluated. [Copyright &y& Elsevier]
- Published
- 2011
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- View/download PDF
46. Evidence for spin mixing in holmium thin film and crystal samples.
- Author
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Usman, I. T. M., Yates, K. A., Moore, J. D., Morrison, K., Pecharsky, V. K., Gschneidner, K. A., Verhagen, T., Aarts, J., Zverev, V. I., Robinson, J. W. A., Witt, J. D. S., Blamire, M. G., and Cohen, L. F.
- Subjects
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SOLID state electronics , *THIN films , *TRANSITION metals , *CRYOELECTRONICS , *SPECTRUM analysis - Abstract
In a number of recent experiments, holmium has been shown to promote spin-triplet pairing when in proximity to a spin-singlet superconductor. The condition for the support of spin-triplet pairing is that the ferromagnet should have an inhomogeneous magnetic state at the interface with the superconductor. Here we use Andreev reflection spectroscopy to study the properties of single ferromagnet/superconductor interfaces formed of holmium and niobium, as a function of the contact resistance of the junction between them. We find that both single-crystal and c-axis-oriented thin-film holmium show unusual behavior for low junction contact resistance, characteristic of spin-mixing-type properties, which are thought necessary to underpin spin-triplet formation. We also explore whether this signature is observed when the junction is formed of Ni0.19Pd0.81 and niobium. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
47. Localization of conduction electrons in the ferromagnetic clusters AuFe.
- Author
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Prokhorov, A. S., Zhukova, E. S., Gorshunov, B. P., Hesselberth, M. B. S., Aarts, J., Nieuwenhuys, G. J., Kaiser, S., and Dressel, M.
- Subjects
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LOCALIZATION theory , *CONDUCTION electrons , *FERROMAGNETISM , *IRON ions , *OPTICS - Abstract
The optical-conductivity spectra of concentrated solutions Au1 − xFe x with x = 17 and 22 at % have been measured in a frequency range of (10–33) × 103 cm−1 at room temperature. The results are analyzed together with previous optical data obtained for compounds with x = 4–12 at %. It is found that the magnetic contributions σmagn = σAuFe − σAu to dc and low-frequency(10 cm−1) conductivities for an Fe concentration below 4 at % are almost equal, while the low-frequency magnetic contribution for larger concentrations is significantly larger than the dc one. An absorption band at frequencies of 1000–3000 cm−1 has been found for samples with concentrations x = 6–22 at %. The observed phenomena are attributed to the localization of electrons inside clusters containing ferromagnetically ordered iron ions. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
48. Resistive transitions in Nb/Cu0.41Ni0.59/Nb trilayers.
- Author
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Prischepa, S. L., Cirillo, C., Bell, C., Kushnir, V., Aarts, J., Attanasio, C., and Kupriyanov, M.
- Subjects
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SUPERCONDUCTING composites , *FERROMAGNETIC resonance , *ELECTRIC resistance , *ELECTRIC impedance , *ELECTRICITY - Abstract
The superconducting phase transition in Nb/Cu0.41Ni0.59/Nb trilayers, with superconducting (S) Nb and ferromagnetic (F) Cu0.41Ni0.59, has been experimentally studied as a function of the F-layer thickness by measuring the temperature dependence of the electrical resistance R( T). It is shown that the shape and the width of the R( T) curves depends on the Cu0.41Ni0.59 thickness, in particular in the regime where π is the coupling between the S layers, which can be expected. To explain the data, we developed a qualitative model which makes the interconnection between the superconducting phase transition and the 0 to π transition in SFS structures are more evident. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
49. Terahertz spectroscopy of AuFe spin glasses.
- Author
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Prokhorov, A. S., Anzin, V. B., Vitukhnovskiĭ, D. A., Zhukova, E. S., Spektor, I. E., Gorshunov, B. P., Vongtragool, S., Hesselberth, M. B. S., Aarts, J., Nieuwenhuys, G. J., Dumm, M., Faltermeier, D., Kaiser, S., Yasin, S., Dressel, M., and Drichko, N.
- Subjects
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SPIN glasses , *ELLIPSOMETRY , *OPTICAL properties of metallic films , *PLASMA frequencies , *ELECTRON mobility , *ELECTRIC conductivity , *SPIN exchange , *TERAHERTZ technology - Abstract
The electrodynamic response of spin glasses (in the form of thin AuFe films) in the terahertz frequency range has been studied using backward-wave oscillator (BWO) spectroscopy (10–40 cm−1) and optical ellipsometry (5000–33000 cm−1) techniques at temperatures from 5 to 295 K. The room-temperature dynamic conductivity spectra of AuFe films are typical of metals and can be described within the framework of the Drude theory of conduction by free charge carriers. Changes in the microscopic parameters of charge carriers in AuFe films with increasing iron content, which are related to additional scattering of carriers on the impurity magnetic moments, have been studied on the quantitative level, including the carrier relaxation frequency and characteristic time, plasma frequency, and conductivity. It is established that the spin-glass phase at a temperature of ∼5 K exhibits dispersion of the conductivity in the frequency range 10–40 cm−1, which can be related to the appearance of a mobility gap in the subsystem of free electrons involved in the RKKY interaction between magnetic centers (Fe atoms). [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
50. Crystal structure of (La,Ca)MnO 3 ultrathin films deposited on SrTiO 3 substrates.
- Author
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Qin, Y. L., Zandbergen, H. W., Yang, Z. Q., and Aarts, J.
- Subjects
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TRANSMISSION electron microscopy , *ELECTRON diffraction , *ELECTRON microscopy , *HIGH energy electron diffraction , *LIQUID crystal films , *PARTICLES (Nuclear physics) - Abstract
Epitaxial La 1- x Ca x MnO 3 ( x ???0.33) ultrathin films with thickness between 3 and 6?nm have been grown on (001) SrTiO 3 substrates by sputter deposition. The films do not exhibit an insulator-metal transition as a function of temperature, which is normal in thicker films. High-resolution transmission electron microscopy and electron diffraction were used to investigate the crystal structure. It was found that the films grow coherently on the substrates and are perfectly crystalline. Their crystal structure was determined to be a body-centred orthorhombic structure with space group Imma , instead of the orthorhombic Pnma bulk structure. This structure change is probably responsible for the insulating property of the films. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
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