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1. Superconductivity and magnetism on flux grown single crystals of NiBi3

Author

Silva, B., Luccas, R. F., Nemes, N. M., Hanko, J., Kulkarni, M. R. Osorio P., Mompean, F., Garcia-Hernandez, M., Ramos, M. A., Vieira, S., and Suderow, H.

Subjects
Condensed Matter - Superconductivity
Abstract

We present resistivity, magnetization and specific heat measurements on flux grown single crystals of NiBi3. We find typical behavior of a type-II superconductor, with, however, a sizable magnetic signal in the superconducting phase. There is a hysteretic magnetization characteristic of a ferromagnetic compound. By following the magnetization as a function of temperature, we find a drop at temperatures corresponding to the Curie temperature of ferromagnetic amorphous Ni. Thus, we assign the magnetism in NiBi$_3$ crystals to amorphous Ni impurities. more...

Published
2013
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2. Low-temperature specific heat of graphite and CeSb2: Validation of a quasi-adiabatic continuous method

Author

Pérez-Castañeda, T., Azpeitia, J., Hanko, J., Fente, A., Suderow, H., and Ramos, M. A.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Disordered Systems and Neural Networks
Abstract

We present the application of a fast quasi-adiabatic continuous method to the measurement of specific heat at 4He temperatures, which can be used for the study of a wide range of materials. The technique can be performed in the same configuration used for the relaxation method, as the typical time constants between calorimetric cell and thermal sink at 4.2 K are chosen to be of the order of tau~30 s. The accuracy in the absolute values have been tested by comparing them to relaxation-method results obtained in the same samples (performed in situ using the same set-up), with a deviation between the absolute values < 3% in the whole temperature range. This new version of the continuous calorimetric method at low temperatures allows us to completely characterize and measure a sample within a few hours with a high density of data points, whereas when employing other methods we typically need a few days. An exhaustive study has been performed for reproducibility to be tested. In the present work, we have applied this method to two different substances: CeSb2, which exhibits three magnetic transitions at 15.5 K, 11.7 K and 9.5 K, and graphite, both highly-oriented pyrolytic graphite (HOPG) and natural crystals. Our results on these graphites are discussed in comparison with previous published data on different kinds of graphite samples., Comment: 21 pages, 8 figures more...

Published
2013
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3. Interplay of frustration and magnetic field in the two-dimensional quantum antiferromagnet Cu(tn)Cl$_2$

Author

Orendáčová, A., Čižmár, E., Xia, J. S., Yin, L., Pajerowski, D. M., Sedláková, L., Hanko, J., Zeleňák, V., Kajňaková, M., Zvyagin, S., Orendáč, M., Feher, A., Wosnitza, J., and Meisel, M. W.

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

Specific heat and ac magnetic susceptibility measurements, spanning low temperatures ($T \geq 40$ mK) and high magnetic fields ($B \leq 14$ T), have been performed on a two-dimensional (2D) antiferromagnet Cu(tn)Cl$_{2}$ (tn = C$_{3}$H$_{10}$N$_{2}$). The compound represents an $S = 1/2$ spatially anisotropic triangular magnet realized by a square lattice with nearest-neighbor ($J/k_{B} = 3$ K), frustrating next-nearest-neighbor ($0 < J^{\prime}/J < 0.6$), and interlayer ($|J^{\prime \prime}/J| \approx 10^{-3}$) interactions. The absence of long-range magnetic order down to $T = $ 60 mK in $B = 0$ and the $T^{2}$ behavior of the specific heat for $T \leq 0.4$ K and $B \geq 0$ are considered evidence of high degree of 2D magnetic order. In fields lower than the saturation field, $B_{\text{sat}} = 6.6$ T, a specific heat anomaly, appearing near 0.8 K, is ascribed to bound vortex-antivortex pairs stabilized by the applied magnetic field. The resulting magnetic phase diagram is remarkably consistent with the one predicted for the ideal square lattice, except that $B_{\text{sat}}$ is shifted to values lower than expected. Potential explanations for this observation, as well as the possibility of a Berezinski-Kosterlitz-Thouless (BKT) phase transition in a spatially anisotropic triangular magnet with the N\'{e}el ground state, are discussed., Comment: 8 pages, 9 figures more...

Published
2009
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4. Magnetocaloric Study of Spin Relaxation in `Frozen' Dipolar Spin Ice Dy2Ti2O7

Author

Orendac, M., Hanko, J., Cizmar, E., Orendacova, A., Shirai, M., and Bramwell, S. T.

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

The magnetocaloric effect of polycrystalline samples of pure and Y-doped dipolar spin ice Dy2Ti2O7 was investigated at temperatures from nominally 0.3 K to 6 K and in magnetic fields of up to 2 T. As well as being of intrinsic interest, it is proposed that the magnetocaloric effect may be used as an appropriate tool for the qualitative study of slow relaxation processes in the spin ice regime. In the high temperature regime the temperature change on adiabatic demagnetization was found to be consistent with previously published entropy versus temperature curves. At low temperatures (T < 0.4 K) cooling by adiabatic demagnetization was followed by an irreversible rise in temperature that persisted after the removal of the applied field. The relaxation time derived from this temperature rise was found to increase rapidly down to 0.3 K. The data near to 0.3 K indicated a transition into a metastable state with much slower relaxation, supporting recent neutron scattering results. In addition, magnetic dilution of 50 % concentration was found to significantly prolong the dynamical response in the milikelvin temperature range, in contrast with results reported for higher temperatures at which the spin correlations are suppressed. These observations are discussed in terms of defects and loop correlations in the spin ice state., Comment: 9 figures, submitted to Phys. Rev. B more...

Published
2006
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9. The influence of microstructure on magnetic properties of nanocrystalline Fe-Pt-Nb-B permanent magnet ribbons.

Author

Randrianantoandro, N., Crisan, A. D., Crisan, O., Marcin, J., Kovac, J., Hanko, J., Grenèche, J. M., Svec, P., Chrobak, A., and Skorvanek, I.

Subjects
MAGNETICS, NANOCOMPOSITE materials, MICROSTRUCTURE, X-ray diffraction, TRANSMISSION electron microscopy, MAGNETISM
Abstract

A FePt-based hard-magnetic nanocomposite of exchange spring type was prepared by isothermal annealing of melt-spun Fe52Pt28Nb2Bubscript>18 (atomic percent) ribbons. The relationship between microstructure and magnetic properties was investigated by qualitative and quantitative structural analysis based on the x-ray diffraction, transmission electron microscopy, and 57Fe Mössbauer spectrometry on one hand and the superconducting quantum interference device magnetometry on the other hand. The microstructure consists of L10-FePt hard-magnetic grains (15-45 nm in diameter) dispersed in a soft magnetic medium composed by A1 FePt, Fe2B, and boron-rich (FeB)PtNb remainder phase. The ribbons annealed at 700 °C for 1 h exhibit promising hard-magnetic properties at room temperature: Mr/Ms=0.69; Hc=820 kA/m and (BH)max=70 kJ/m3. Strong exchange coupling between hard and soft magnetic phases was demonstrated by a smooth demagnetizing curve and positive δM-peak in the Henkel plot. The magnetic properties measured from 5 to 750 K reveals that the hard characteristics remains rather stable up to 550 K, indicating a good prospect for the use of these permanent magnets in a wide temperature range. [ABSTRACT FROM AUTHOR] more...

Published
2010
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10. Charge density wave in layered La1-xCexSb2

Author

Luccas, Roberto F., Fente, Antón, Hanko, J., Correa Orellana, Alexandre, Herrera, E., Climent-Pascual, Esteban, Azpeitia-Urkia, Jon, Pérez-Castañeda, T., Osorio, M. R., Salas, Eduardo, Nemes, N. M., Mompean, F. J., García-Hernández, M., Rodrigo, J. G., Ramos, M. A., Guillamón, Isabel, Vieira, S., Suderow, Hermann, UAM. Departamento de Física de la Materia Condensada, Ministerio de Economía y Competitividad (España), European Commission, European Cooperation in Science and Technology, Comunidad de Madrid, Consejo Superior de Investigaciones Científicas (España), Colciencias (Colombia), and Ministerio de Ciencia e Innovación (España) more...

Subjects
Condensed Matter::Materials Science, Magnetic field, Condensed Matter::Superconductivity, Física, Condensed Matter::Strongly Correlated Electrons, Layered La1−xCexSb2, Distortion, Anisotropic metals
Abstract

The layered rare-earth diantimonides RSb2 are anisotropic metals with generally low electronic densities whose properties can be modified by substituting the rare earth. LaSb2 is a nonmagnetic metal with a low residual resistivity presenting a low-temperature magnetoresistance that does not saturate with the magnetic field. It has been proposed that the latter can be associated to a charge density wave (CDW), but no CDW has yet been found. Here we find a kink in the resistivity above room temperature in LaSb2 (at 355 K) and show that the kink becomes much more pronounced with substitution of La by Ce along the La1−xCexSb2 series. We find signatures of a CDW in x-ray scattering, specific heat, and scanning tunneling microscopy (STM) experiments in particular for x ≈ 0.5. We observe a distortion of rare-earth–Sb bonds lying in-plane of the tetragonal crystal using x-ray scattering, an anomaly in the specific heat at the same temperature as the kink in resistivity and charge modulations in STM. We conclude that LaSb2 has a CDW which is stabilized in the La1−xCexSb2 series due to substitutional disorder, This work was supported by the Spanish MINECO (FIS2014-54498-R, MAT2011-27470-C02-02, and CSD-2009-00013), by the European Union (Graphene Flagship Contract No. CNECT-ICT-604391 and COST MP1201 action), and by the Comunidad de Madrid through programs Nanofrontmag-CM (S2013/MIT-2850) and MAD2D-CM (S2013/MIT-3007).We acknowledge MINECO and CSIC for financial support and for provision of synchrotron radiation facilities and would like to thank the SpLine BM25 staff for assistance in using the beamline more...

Published
2015
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12. Charge density wave in layered La1-xCexSb2

Author

Ministerio de Economía y Competitividad (España), European Commission, European Cooperation in Science and Technology, Comunidad de Madrid, Consejo Superior de Investigaciones Científicas (España), Colciencias (Colombia), Ministerio de Ciencia e Innovación (España), Luccas, Roberto F., Fente, Antón, Hanko, J., Correa Orellana, Alexandre, Herrera, E., Climent-Pascual, Esteban, Azpeitia-Urkia, Jon, Pérez-Castañeda, T., Osorio, M. R., Salas, Eduardo, Nemes, N. M., Mompean, F. J., García-Hernández, Mar, Rodrigo, J. G., Ramos, M. A., Guillamón, Isabel, Vieira, S., Suderow, Hermann, Ministerio de Economía y Competitividad (España), European Commission, European Cooperation in Science and Technology, Comunidad de Madrid, Consejo Superior de Investigaciones Científicas (España), Colciencias (Colombia), Ministerio de Ciencia e Innovación (España), Luccas, Roberto F., Fente, Antón, Hanko, J., Correa Orellana, Alexandre, Herrera, E., Climent-Pascual, Esteban, Azpeitia-Urkia, Jon, Pérez-Castañeda, T., Osorio, M. R., Salas, Eduardo, Nemes, N. M., Mompean, F. J., García-Hernández, Mar, Rodrigo, J. G., Ramos, M. A., Guillamón, Isabel, Vieira, S., and Suderow, Hermann more...

Abstract

The layered rare-earth diantimonides RSb2 are anisotropic metals with generally low electronic densities whose properties can be modified by substituting the rare earth. LaSb2 is a nonmagnetic metal with a low residual resistivity presenting a low-temperature magnetoresistance that does not saturate with the magnetic field. It has been proposed that the latter can be associated to a charge density wave (CDW), but no CDW has yet been found. Here we find a kink in the resistivity above room temperature in LaSb2 (at 355 K) and show that the kink becomes much more pronounced with substitution of La by Ce along the La1-xCexSb2 series. We find signatures of a CDW in x-ray scattering, specific heat, and scanning tunneling microscopy (STM) experiments in particular for x≈0.5. We observe a distortion of rare-earth-Sb bonds lying in-plane of the tetragonal crystal using x-ray scattering, an anomaly in the specific heat at the same temperature as the kink in resistivity and charge modulations in STM. We conclude that LaSb2 has a CDW which is stabilized in the La1-xCexSb2 series due to substitutional disorder. more...

Published
2015

13. Charge density wave in layeredLa1−xCexSb2

Author

Luccas, R. F., primary, Fente, A., additional, Hanko, J., additional, Correa-Orellana, A., additional, Herrera, E., additional, Climent-Pascual, E., additional, Azpeitia, J., additional, Pérez-Castañeda, T., additional, Osorio, M. R., additional, Salas-Colera, E., additional, Nemes, N. M., additional, Mompean, F. J., additional, García-Hernández, M., additional, Rodrigo, J. G., additional, Ramos, M. A., additional, Guillamón, I., additional, Vieira, S., additional, and Suderow, H., additional more...

Published
2015
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16. Interplay of frustration and magnetic field in the two-dimensional quantum antiferromagnet Cu(tn)Cl-2

Author

Orendacova, A., Cizmar, E., Sedlakova, L., Hanko, J., Kajnakova, M., Orendac, M., Feher, A., Xia, J., Yin, L., Pajerowski, D., Meisel, M., Zelenak, V., Zvyagin, S., Wosnitza, J., Orendacova, A., Cizmar, E., Sedlakova, L., Hanko, J., Kajnakova, M., Orendac, M., Feher, A., Xia, J., Yin, L., Pajerowski, D., Meisel, M., Zelenak, V., Zvyagin, S., and Wosnitza, J. more...

Abstract

Specific heat and ac magnetic susceptibility measurements, spanning low temperatures (T >= 40 mK) and high-magnetic fields (B <= 14 T), have been performed on a two-dimensional (2D) antiferromagnet Cu(tn)Cl-2 (tn=1,3-diaminopropane=C3H10N2). The compound represents a S = 1/2 spatially anisotropic triangular antiferromagnet realized by a square lattice with nearest-neighbor (J/kB = 3 K), frustrating next-nearest-neighbor (0 < J'/J < 0.6), and interlayer (|J''/J| approximate to 10-3) interactions. The absence of long-range magnetic order down to T = 60 mK in B = 0 and the T-2 behavior of the specific heat for T <= 0.4 K and B >= 0 are considered evidence of a high degree of 2D magnetic order. In fields lower than the saturation field, Bsat = 6.6 T, a specific heat anomaly, appearing near 0.8 K, is ascribed to bound vortex-antivortex pairs stabilized by the applied magnetic field. The resulting magnetic phase diagram is remarkably consistent with the one predicted for a square lattice without a frustrating interaction, expect that Bsat is shifted to values lower than expected. Potential explanations for this observation, as well as the possibility of a Berezinski-Kosterlitz-Thouless (BKT) phase transition in a spatially anisotropic triangular magnet with the collinear Neel ground state, are discussed. more...

Published
2009

17. The influence of magnetic field on the two-dimensional quantum antiferromagnet Cu(tn)Cl2: an intriguing magnetic phase diagram

Author

Orendacova, A., Cizmar, E., Sedlakova, L., Hanko, J., Kajnakova, M., Zelenak, V., Xia, J. S., Yin, L., Pajerowski, D. M., Zvyagin, S. A., Wosnitza, J., Orendac, M., Feher, A., Meisel, M. W., Orendacova, A., Cizmar, E., Sedlakova, L., Hanko, J., Kajnakova, M., Zelenak, V., Xia, J. S., Yin, L., Pajerowski, D. M., Zvyagin, S. A., Wosnitza, J., Orendac, M., Feher, A., and Meisel, M. W. more...

Abstract

Specic heat and magnetic susceptibility measurements, spanning low temperatures (T ≥ 40 mK) and high magnetic elds (B ≤ 14 T), have been performed on Cu(tn)Cl2 (tn = C3H10N2), a two-dimensional (2D) S = 1/2 spatially anisotropic triangular antiferromagnet realized by a square lattice with nearest- neighbor (J=kB = 3 K), frustrating next-nearest-neighbor (0 < J'/J < 0.6), and interlayer (|J''/kB| <3 mK) interactions [1]. The absence of long-range magnetic order down to T = 60 mK in B = 0 and the T2 behavior of the specific heat for T ≤ 0.4 K and B ≥ 0 are considered evidence of 2D magnetic correlations. In fields lower than the saturation field, Bsat = 6.6 T, a specific heat anomaly, appearing near 0.8 K, is interpreted as a Berezinski-Kosterlitz-Thouless (BKT) phase transition. The magnetic phase diagram is remarkably consistent with the theoretical predictions [2], except for the point that Bsat(T -> 0) is shifted to values significantly lower than expected. Potential explanations for this observation will be discussed. more...

Published
2009

26. Reply

Author

Hanko, J., primary and Courtney, A., additional

Published
2009
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28. Interplay of frustration and magnetic field in the two-dimensional quantum antiferromagnetCu(tn)Cl2

Author

Orendáčová, A., primary, Čižmár, E., additional, Sedláková, L., additional, Hanko, J., additional, Kajňaková, M., additional, Orendáč, M., additional, Feher, A., additional, Xia, J. S., additional, Yin, L., additional, Pajerowski, D. M., additional, Meisel, M. W., additional, Zeleňák, V., additional, Zvyagin, S., additional, and Wosnitza, J., additional more...

Published
2009
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34. A double blind, randomised, parallel group study to investigate the dose equivalence of Dysport and Botox in the treatment of cervical dystonia

Author

Odergren, T, primary, Hjaltason, H, additional, Kaakkola, S, additional, Solders, G, additional, Hanko, J, additional, Fehling, C, additional, Marttila, R J, additional, Lundh, H, additional, Gedin, S, additional, Westergren, I, additional, Richardson, A, additional, Dott, C, additional, and Cohen, H, additional more...

Published
1998
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37. ELECTRICAL FIELD STIMULATION IN CEREBRAL AND PERIPHERAL ARTERIES: A CRITICAL EVALUATION OF THE CONTRACTILE RESPONSE.

Author

HARDEBO, J. E., HANKO, J., KÅHRSTRÖM, J., and OWMAN, C.

Abstract

Electrical field stimulation with recording of isometric contraction in vitro was carried out on small circular segments of pial arteries, in comparison with peripheral arteries from several regions of rat, rabbit, cow, cat, dog and man., It was found that tetrodotoxin (TTX)-resistant contractions were obtained more readily in pial arteries of various species, including man, than in peripheral arteries of similar size. In fact, it was not possible to obtain a purely neurogenic response - without a TTX-resistant change in tone - in any pial vessels tested., The stimulation parameters that induced TTX-resistant contraction in pial arteries were similar to those weak parameters that could reveal a purely neurogenic response in certain other arteries, such as rabbit central ear artery and rabbit and feline mesenteric arteries. In these arteries, release of noradrenaline (NA) onto postjunctional α-adrenoreceptors was found to be fully responsible for the contraction. The contractile response could be considerably potentiated by blockade of neuronal and extraneuronal uptake, prejunctional α-receptor blockade, and 4-aminopyridine (4-AP)-induced enhancement of transmitter release. Addition of compounds to prevent oxidation of released NA (EDTA by its ability to bind metal ions, and ascorbic acid-glutathione, which prevents formation of free radicals) did not enhance the neurogenic response., However, not even under any of these conditions was it possible to reveal a purely neurogenic response in cerebral arteries. Only TTX-resistant contractions, likely to be due to direct smooth muscle activation, were obtained. The explanation may be morphological differences related to myogenic propagation, probably together with poorly sensitive α-adrenoreceptors, in these pial arteries. The situation was further complicated by the fading of the TTX-resistant contraction which often occurred upon repeated stimulation., Therefore, acceptance of partial blockade by TTX as a criterion for a neurogenic response in cerebral vessels, as by several previous investigators, may lead to misinterpretation of the true nature of the response. Hence, when studying neurogenic mechanisms in vitro in these arteries, parameters other than vascular tone should be recorded in conjunction with electrical field stimulation, such as registration of junction potentials and measurements of released transmitter. [ABSTRACT FROM AUTHOR] more...

Published
1986
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38. NEUROPEPTIDE Y INDUCES AND MODULATES VASOCONSTRICTION IN INTRACRANIAL AND PERIPHERAL VESSELS OF ANIMALS AND MAN.

Author

HANKO, J. H., TÖRNEBRANDT, K., HARDEBO, J. E., KÅHRSTRÖM, J., NOBIN, A., and OWMAN, CH.

Abstract

Neuropeptide Y (NPY) has recently been reported to coexist with noradrenaline (NA) in central as well as peripheral noradrenergic nerves. NPY-containing nerve fibres are particularly numerous around blood vessels., Studies were performed on isolated pial arteries as well as on arteries and veins from several peripheral vascular beds from rabbit, cat and man. NPY induced a varying degree of direct contraction of the vessels with an EAm up to 15 mN. Pial arteries were more sensitive than peripheral arteries to NPY (mean EC50 = 7.6 × 10−9 M). The presence of NPY did not cause any consistent or significant potentiation of the contractile response to NA in any of the vessels tested., Transmural electrical stimulation of the perivascular nerves (including blockade with tetrodotoxin) was performed mainly with auricular artery from the rabbit. Blocking experiments confirmed that the neurogenic contraction was mediated by noradrenergic-type fibres. NPY caused a concentration-related potentiation of the neurally evoked contractile response. The peptide also potentiated the tetrodotoxin-resistant probably non-neurogenic contractions obtained during enhanced electrical field stimulation., It is concluded that NPY interacts with NA during sympathetic nerve activation primarily through a presynaptic effect. [ABSTRACT FROM AUTHOR] more...

Published
1986
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39. Photoluminescence and Magnetism in the New Magnetic Semiconductors:  K<INF>2</INF>Cd<INF>3(1</INF><INF>-</INF><INF>x</INF><INF></INF><INF>)</INF>Mn<INF>3</INF><INF>x</INF><INF></INF>S<INF>4</INF>

Author

Axtell, E. A., III, Hanko, J., Cowen, J. A., and Kanatzidis, M. G.

Abstract

A new family of magnetic semiconductors, K2Cd3(1-x)Mn3xS4, prepared from molten K2</inf>Sx is reported. For x ≤ 0.6, the compounds crystallize in the K2Cd3S4 structure type. The cell volumes of the series obey Vegard's Law for solid solutions. The compounds range in color from yellow through orange brown to red and possess platelike morphologies. A structural transformation occurs between x = 0.7 and x = 0.9. Red plates of K2Cd0.4Mn2.6S4 (x = 0.87) crystallize in the space group Ccca with a = 5.9217(8) Å, b = 13.531(1) Å, c = 11.0696(8) Å, and V = 887.0(1) Å3. The end member, K2Mn3S4, crystallizes in the space group Ccca with a = 11.0637(7) Å, b = 26.830(2) Å c = 5.8180(4) Å, and V = 1727 Å3. For x ≤ 0.6, the compounds form as (M3S4)n2n- layers, interspersed by K+ cations. These layers are composed only of M3S42- units shaped like truncated cubes. When x = 0.87, a new structure related to that of Cs2Mn3S4 is observed. The end member of the series (i.e., x = 1) K2Mn3S4 is revealed to have a related yet surprising structure. The compounds display room-temperature band gaps ranging from 2.79 to 2.92 eV. Absorptions in the mid-gap region, due to Mn2+-based d−d transitions, are also observed. The compounds are strongly emissive in the visible spectrum at room temperature, with the light emission shifted to the red immediately upon the introduction of small amounts of manganese. The magnetic properties of these compounds evolve from classical paramagnetic to spin glass as a function of x. For x ≥ 0.05, the compounds deviate from Curie−Weiss behavior. Antiferromagnetic coupling is observed in all cases. With very high Mn content transitions to magnetically complex phases are observed with possible spin-glass-like behavior. more...

Published
2001

40. Home condition and lead levels: A case study from the homes of pre-schoolers in Mt. Pleasant, Michigan

Author

Francek, Mark, Pan, Vicki, Hanko, J. H., and Makimaa, Bradley

Abstract

This study assessed the relationship between soil and dust lead (Pb) levels and building material, exterior and interior (including window sill) condition, pet ownership, and the presence of a fireplace. Four dust samples and one soil sample were collected from the homes of 42 preschoolers in Mt. Pleasant, Michigan. The results of atomic absorption spectroscopy revealed that median Pb levels for both soil and dust were two to ten times higher for homes with wood exteriors. Significant variation in soil and dust Pb levels also occurred as a function of home wall condition. Poorly maintained homes had the highest Pb levels. No consistent significant relationship was observed between home Pb levels and a) the presence of pets and b) the presence of a fireplace. On the whole, households participating in the study had low Pb levels. This finding can be attributed to excellent home upkeep by the part of study participants. more...

Published
1994
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41. A<INF>2</INF>CuP<INF>3</INF>S<INF>9</INF> (A = K, Rb), Cs<INF>2</INF>Cu<INF>2</INF>P<INF>2</INF>S<INF>6</INF>, and K<INF>3</INF>CuP<INF>2</INF>S<INF>7</INF>: New Phases from the Dissolution of Copper in Molten Polythiophosphate Fluxes

Author

Hanko, J. A., Sayettat, J., Jobic, S., Brec, R., and Kanatzidis, M. G.

Abstract

The reaction of Cu with a molten mixture of A2S/P2S5 (A = K, Rb, Cs) produced the quaternary compounds A2CuP3S9 (A = K, Rb) and Csnf>2Cu2P2S6. The reaction of Cu with a molten mixture of K2S/P2S5/S produced the quaternary compound K3CuP2S7. A2CuP3S9 (A = K, Rb); I, II, respectively) crystallizes in the space group P21/n (no. 14) for I:  a = 6.8331(6) Å, b = 23.562(2) Å, c = 9.5415(7) Å, β = 100.242(7)°, Z = 4, V = 1511.8(4) Å3, ρcalc = 2.298 g/cm3. Cs2Cu2P2S6 (III) crystallizes in the space group P21/c (no. 14) with a = 9.538(3) Å, b = 12.793(4) Å, c = 10.429(4) Å, β = 103.76(2)°, Z = 4, V = 1236.1(7) Å3, ρcalc = 3.478 g/cm3. K3CuP2S7 (IV) crystallizes in the space group P21/a (no. 14) with a = 13.113(5) Å, b = 6.702(3) Å, c = 15.141(7) Å, β = 115.13(1)°, Z = 4, V = 1315(1) Å3, ρcalc = 2.35 g/cm3. The structure of I−II consists of novel one-dimensional [CuP3S9]n2n- chains separated by A+ cations. The chains run along the crystallographic b-axis. The Cu+ cation is in tetrahedral coordination with the cyclic [P3S9]3- anion, a new polythiophosphate unit. The structure of III has one-dimensional [Cu2P2S6]n2n- chains separated by Cs+ cations. The chains consists of alternating [Cu2]2+ dimers linked by the ethane-like [P2S6]4- units. The structure of IV is also one-dimensional, with [CuP2S7]n3n- chains separated by K+ ions. The Cu+ ions are in a slightly distorted trigonal planar environment with the [P2S7]4- units. Differential thermal analysis, far-IR, Raman spectroscopy, and optical spectroscopic data are reported. The results of a band structure calculation at the DFT-LMTO level for K2CuP3S9 are also discussed. more...

Published
1998

42. New Quaternary Thiostannates and Thiogermanates A<INF>2</INF>Hg<INF>3</INF>M<INF>2</INF>S<INF>8</INF> (A = Cs, Rb; M = Sn, Ge) through Molten A<INF>2</INF>S<INF>x</INF><INF></INF>. Reversible Glass Formation in Cs<INF>2</INF>Hg<INF>3</INF>M<INF>2</INF>S<INF>8</INF>

Author

Marking, G. A., Hanko, J. A., and Kanatzidis, M. G.

Abstract

Cs2Hg3M2S8 (M = Ge, Sn) were synthesized in 70% and 65% yields by reacting HgS, and Sn or Ge, in molten Cs2Sx at 520 °C. Rb2Hg3Sn2S8 and Rb2Hg3Ge2S8 were synthesized in 42% and 73% yield by reacting the same reagents in molten Rb2Sx at 350 °C. Cs2Hg3M2S8 crystallize in the triclinic space group P&onemacr;. Cs2Hg3Sn2S8:  a = 7.878(2) Å, b = 9.157(3) Å, c = 6.803(2) Å, α = 92.96(2)°, β = 109.45(2)°, γ = 107.81(2)°, V = 434.1(2) Å3, and Dcalc = 5.207 g/cm3. The unit cell of isostructural Cs2Hg3Ge2S8 is a = 7.808(2) Å, b = 9.164(2) Å, c = 6.612(2) Å, α = 92.02(2)°, β = 108.65(2)°g, γ = 108.10(2)°, and V = 419.9(2) Å3. Rb2Hg3M2S8 crystallize in the monoclinic space group P21/c, Rb2Hg3Sn2S8:  a = 10.132(2) Å, b = 6.540(2) Å, c = 13.434(2) Å, β = 97.93(1)°, V = 881.7(6) Å3, and Dcalc = 4.770 g/cm3. The unit cell of isostructural Rb2Hg3Ge2S8 is a = 9.938 (3) Å, b = 6.352 (2) Å, c = 13.117 (3) Å, β = 97.33 (2)°, and V = 821.3 (4) Å3. The structure of Cs2Hg3M2S8 consists of [Hg3M2S8]2- layers separated by Cs+ cations. The layers contain tetrahedral Sn4+ or Ge4+ centers and two types of Hg2+, two coordinate linear and three-coordinate pseudotrigonal centers. The structure of Rb2Hg3M2S8 consists of a 3-dimensional [Hg3M2S8]2- framework with Rb+ cations located within channels of the structure. This structure also contains tetrahedral Sn4+ or Ge4+ centers and two types of Hg2+, the two-coordinate linear type and a four-coordinate “seesaw” geometry. Optical band gaps, determined from single-crystal UV/vis spectroscopy, range from 2.52 eV in the tin-based compounds to 2.89 eV in the germanium-based analogues. Cs2Hg3M2S8 become glasses upon melting. Infrared and Raman spectroscopic characterization of the glasses are reported. more...

Published
1998

43. A double blind, randomised, parallel group study to investigate the dose equivalence of Dysport® and Botox® in the treatment of cervical dystonia

Author

Westergren, I., Odergren, T., Richardson, A., Hjaltason, H., Dott, C., Kaakkola, S., Cohen, H., Solders, G., Hanko, J., Fehling, C., Marttila, R.J., Lundh, H., and Gedin, S.

Abstract

ObjectiveThis study was designed to establish whether a ratio of three units of Dysport ® is equivalent to one unit of Botox ® for the treatment of cervical dystonia. Methods Patients with predominantly rotational cervical dystonia, and a minimum of four previous Botox treatments, were randomised to receive either the clinically indicated dose of Botox or three times that dose in Dysport units. Study botulinum toxin was administered in a double blind fashion, to one or more clinically indicated muscles, at one or more sites per muscle. Patients returned for assessment two, four, eight, and 12 weeks after treatment. Results A total of 73 patients (Dysport, 38; Botox, 35) were entered. The Dysport group received a mean (SD) dose of 477 (131) (range 240-720) Dysport units, and the Botox group received a mean (SD) dose of 152 (45) (range 70-240) Botox units. The mean (SEM) post-treatment Tsui scores for the Dysport group (4.8 (0.3)) and the Botox group (5.0 (0.3)) were not statistically different (p=0.66). The study had 91% power to detect a clinically significant difference of two points. Both groups showed substantial improvement in Tsui score by week 2 (mean (SD); Dysport, 46 (28)%; Botox, 37 (28)%), with a peak effect at week 4 (mean (SD); Dysport, 49 (29)%; Botox, 44 (28)%). A similar response profile was seen for other assessments of efficacy. The duration of effect, assessed by time to retreatment, was also similar (mean (SD); Dysport, 83.9 (13.6) days; Botox, 80.7 (14.4) days; p=0.85). During the study 22 of 38 (58%) Dysport patients reported 39 adverse events, and 24 of 35 (69%) Botox patients reported 56 adverse events (p=0.35). A global assessment of efficacy and safety considered that 29 of 38 (76%) Dysport patients and 23 of 35 (66%) Botox patients were treatment successes (p=0.32). Conclusion Patients with predominantly rotational cervical dystonia treated with the clinically indicated dose of Botox or three times that dose in Dysport units show similar improvements and do not have significantly different safety profiles. more...

Published
1998

44. Immunohistochemical demonstration of vasodilatory peptidergic nerves in brain

Author

Hanko J, Edvinsson L, Fahrenkrug J, Håkanson R, Li, Larsson, Owman C, Ove B Schaffalitzky de Muckadell, and Sundler F

Subjects
Vasodilation, Gastrointestinal Hormones, Cholinergic Fibers, Fluorescent Antibody Technique, Humans, Animals, Rabbits, Cerebral Arteries, Vasoactive Intestinal Peptide