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The microstructures and interfaces of two-phase vertically aligned nanocomposite (VAN) thin films play a key role in the design of spintronic device architectures and their multifunctional properti...

We synthesized mesoporous cobalt titanate (CTO) microrods via the sol–gel method as an outstanding working electrode for the supercapacitor. The mesoporous CTO microrods were amassed in hexagonal shapes of an average width of ∼670 nm, and were composed of nanoparticles of average diameter ∼41 nm. The well crystalline CTO microrods of the hexagonal phase to the R space group possessed an average pore size distribution of 3.92 nm throughout the microrod. The mesoporous CTO microrods with increased textural boundaries played a vital role in the diffusion of ions, and they provided a specific capacitance of 608.4 F g−1 and a specific power of 4835.7 W kg−1 and a specific energy of 9.77 W h kg−1 in an aqueous 2 M KOH electrolyte, which was remarkably better than those of Ti, La, Cr, Fe, Ni, and Sr-based perovskites or their mixed heterostructures supplemented by metal oxides as an impurity. Furthermore, the diffusion-controlled access to the OH− ions (0.27 μs) deep inside the microrod conveyed high stability, a long life cycle for up to 1950 continuous charging–discharging cycles, and excellent capacitance retention of 82.3%. Overall, the mesoporous CTO shows its potential as an electrode for a long-cycle supercapacitor, and provides opportunities for additional enhancement after developing the core–shell hetero-architecture with other metal oxide materials such as MnO2, and TiO2.

High-quality growth of MoS

Structural, dielectric and magnetic properties of nano-size polycrystalline, La2CuMnO6 (LCM) samples were studied in the temperature range 80 K to 300 K. Orthorhombic single phase with space group 'Pnma' was confirmed by Rietveld refinement of XRD peaks. The small-polaron driven dielectric dispersion showed relaxation peaks in the vicinity of low-temperatures. The X-ray absorption spectroscopy (XAS) confirmed the charge states of Cu (2+) and Mn (4+) ions. DC-resistivity analysis supported the thermally activated conduction for high temperature and the variable range hoping (VRH) mechanism of conduction at low-temperature. The deviation of super-exchange angles between B-site cations from an ideal 180º value produced non-collinearity in the antiferromagnetic response of this ceramic and was confirmed canted antiferromagnetic behaviour. Positive Curie temperature along with finite coercivity indicated that the super-exchange interaction between Cu2+ and Mn4+ ions influenced the magnetic behaviour of this ceramics and showed a heterogenous magnetic response.

Eu3+ doped BaZrO3 thin films were deposited on quartz substrates in a wide range of oxygen pressure (1–300 mTorr), using Pulsed laser deposition technique. X-ray diffraction pattern showed the different growth orientation of the films with oxygen pressure ( P O 2 ) . The different growth mechanisms were drawn to explanin the thin films growth mechanism at the different oxygen pressure. Time of flight secondary ion mass spectroscopy analysis exhibited homogeneous distribution of all the elements throughout the depth of the films. The depth profile anaylsis revealed sharp interface at the low P O 2 and broad intermixing region of the films with the substrate at low P O 2 . Transmittance spectra revealed the different optical bandgap with different P O 2 . Excitation spectra showed a broad absorption band centered at 260 nm due to the absorption in the defect states. The emission spectra showed intense emission at 597 nm corresponding to the 5D0→7F1 transition of Eu3+. Apart from this, a broad blue-green emission was observed centered at 440 nm due to the trap levels associated with the oxygen vacancy below the conduction band. The energy transfer mechanism between the host to Eu3+ ion was described via a defect state process. Colour coordintes of the emission spectra showed that colour emission of thin films can be tuned by varying the oxygen pressure. The short-excited state lifetime and high value of internal quantum efficiency make these films potential candidates for light emitting diode application.

The origin of the magnetic interaction in SrCoO2.75 and SrCoO3 thin films has been investigated with the help of their experimental valence band (VB) and the conduction band (CB) at room temperature. The ultraviolet photoemission spectroscopy and the O K-edge X-ray absorption spectroscopy were used to probe the VB and CB of the films respectively. It is found that the negative charge transfer energy (Δ) is contributing to the lowest energy charge fluctuations for the double-exchange ferromagnetic interaction in the systems which is larger in SrCoO2.75 film than SrCoO3 film. The magnetic exchange interactions have been realized from a model derived from the combined VB-CB spectra and the Co L-edge absorption spectra. These results offer a valuable inside into the correlation between the microscopic electronic structure and the macroscopic magnetization in the negative Δ double-exchange ferromagnetic oxides.

In the present paper, the gallium modified lead zirconate titanate ceramics with Zr/Ti = 48/52 (near the morphotropic phase boundary,MPB), having a chemical formula Pb0.98Ga0.02(Zr0.48Ti0.52)0.995O3, was synthesized by a mixed-oxide reaction method and sintered. Analysis of phase formation confirmed the co-existence of two phases (tetragonal and monoclinic symmetry) in the system. Microstructural study by scanning electron microscope showed a non-uniform distribution of large grains over the sample surface and presence of a small amount of micro-size pores. Modulus and impedance studies were carried out at various frequencies (1 kHz-1MHz) and temperatures (300-350?C) and showed the contributions of grains in capacitive and resistive properties of the material. The resistance and capacitance of the complex impedance plots are contributed by grains as observed from the Nyquist plots. The experimental data obtained from the Nyquist plot were implemented in an equivalent electrical circuit (RQC). The value of grain resistance and capacitance were obtained using fitting steps with precision at all temperatures. It is assumed that increase of dielectric constant at higher temperatures is due to the substitution of Ga+ ions at the Pb-site.

In view of their immensely intriguing properties, two-dimensional (2D) materials are being intensely researched in search of novel phenomena and diverse application interests; however, studies on the realization of 2D/2D nanocomposites in the application-worthy thin-film platform are rare. Here we have grown $\mathrm{Mo}{\mathrm{S}}_{2}$-hexagonal boron nitride (hBN) 2D/2D composite thin films on different substrates by the pulsed laser deposition technique and made comparative studies with the pristine $\mathrm{Mo}{\mathrm{S}}_{2}$ and hBN films. The Raman and x-ray photoelectron spectroscopy techniques as well as high-resolution transmission electron microscopy confirm the concomitant presence of both the 1T (conducting) and 2H (semiconducting) polymorphs of $\mathrm{Mo}{\mathrm{S}}_{2}$ in the composite film. Interestingly, a peculiar reentrant semiconductor-metal-insulator transition is seen in the $\mathrm{Mo}{\mathrm{S}}_{2}\ensuremath{-}\mathrm{hBN}$ 2D/2D composite film which is absent in the $\mathrm{Mo}{\mathrm{S}}_{2}$ film, and it correlates well with the signatures of phonon softening seen in temperature-dependent Raman spectroscopy. Furthermore, electrostatic force microscopy reveals the presence of three distinct regions (metallic, semiconducting, and insulating) in the $\mathrm{Mo}{\mathrm{S}}_{2}\ensuremath{-}\mathrm{hBN}$ composite film with differing contact potentials and enhanced propensity for charge transfer with respect to pristine $\mathrm{Mo}{\mathrm{S}}_{2}$. A triboelectric nanogenerator device containing biphasic $\mathrm{Mo}{\mathrm{S}}_{2}\ensuremath{-}\mathrm{hBN}$ composite film as an electron acceptor exhibits more than twofold (sixfold) enhancement in peak-to-peak output voltage as compared to the pristine $\mathrm{Mo}{\mathrm{S}}_{2}$ (hBN) film. These observations bring out the potential of 2D/2D nanocomposite thin films for unfolding emergent phenomena and technological applications.

The present study reports on the structural and magnetic phase transitions in Pr-doped polycrystalline Tb0.6Pr0.4MnO3, using high-resolution neutron powder diffraction (NPD) collected at SINQ spallation source, to emphasize the suppression of the sinusoidal magnetic structure of pure TbMnO3 and the evolution to a collinear A-type antiferromagnetic ordering. The phase purity, Jahn–Teller distortion, and one-electron bandwidth for eg orbital of Mn3+ cation have been calculated for polycrystalline Tb0.6Pr0.4MnO3, in comparison to the parent materials TbMnO3 and PrMnO3, through the Rietveld refinement study from x-ray diffraction data at room temperature, which reveals the GdFeO3 type orthorhombic structure of Tb0.6Pr0.4MnO3 having Pnma space group symmetry. The temperature-dependent zero field-cooled and field-cooled dc magnetization study at low temperature down to 5 K reveals a variation in the magnetic phase transition due to the effect of Pr3+ substitution at the Tb3+ site, which gives the signature of the antiferromagnetic nature of the sample, with a weak ferromagnetic component at low temperature-induced by an external magnetic field. The field-dependent magnetization study at low temperatures gives the weak coercivity having the order of 2 kOe, which is expected due to the canted-spin arrangement or ferromagnetic nature of Terbium ordering. The NPD data for Tb0.6Pr0.4MnO3 confirms that the nuclear structure of the synthesized sample maintains its orthorhombic symmetry down to 1.5 K. Also, the magnetic structures have been solved at 50 K, 25 K, and 1.5 K through the NPD study, which shows an A-type antiferromagnetic spin arrangement having the magnetic space group Pn′ma′.

We have investigated the structural and magnetic phase transitions in Sr doped polycrystalline Tb0.55Sr0.45MnO3, using temperature-dependent high-resolution neutron powder diffraction in the HRPT diffractometer at PSI to address the origin of magnetization reversal at low temperature. The solid solution Tb0.55Sr0.45MnO3 crystallizes in O′ type orthorhombic structure having the Pnma symmetry. The substitution of the divalent cation of Sr2+ at the site of Tb3+ dilutes the Mn–Tb interaction and affects the magnetic structure, which was observed by the field and temperature-dependent dc magnetization and neutron diffraction study. The temperature-dependent zero field-cooled and field cooled dc magnetization study reveals the indication of spin reversal phenomena, which is the nature of canted antiferromagnetic or ferrimagnetic transition at 100 Oe because of Mn–Mn sub-lattices interaction below 65 K. By increasing the applied magnetic field up to 20 kOe, a weak ferromagnetic type of behaviour is observed. The field-dependent magnetization shows weak coercivity due to the canted spin structure at low temperatures. The low-temperature neutron diffraction study of polycrystalline Tb0.55Sr0.45MnO3 reveals the non-collinear canted antiferromagnetic structure due to Tb ordering at 1.5 K, which turns into a non-collinear ferromagnetic structure along with spin canting followed by the spin reversal phenomena at 25 K.

This is the novel report on the rapid synthesis of single phase BiFeO3 nanorods by novel hot wall assisted spray pyrolysis system. The deposition has been carried out in an indigenously fabricated system and the entire process is completed in 4 s time duration. The structural, morphological, optical and magnetic properties of BiFeO3 nanorods have been studied in the work. The mechanism of growth of BiFeO3 nanorods has been explained extensively. The magnetic studies carried out with SQUID-VSM results BiFeO3 nanorods showing higher saturated magnetization in comparing with previous reports.

Relationship between magnetism and structure of Cu-doped ZnO was investigated at macroscopic and microscopic levels. Thin Zn1−xCuxO films (x = 0.02, 0.04, 0.07 and 0.10) were prepared by a pulsed laser deposition and characterized via superconducting quantum interference device (SQUID) magnetometry, high-resolution x-ray diffraction, and Cu K-edge and Zn K-edge x-ray absorption, x-ray linear dichroism and x-ray circular magnetic dichroism spectroscopy. Even though the samples exhibit room-temperature ferromagnetism with magnetization that increases with Cu concentration, we did not detect signatures of local magnetic moments associated with Cu atoms, as evidenced by the lack of any XMCD signal. The host ZnO wurtzite lattice is not significantly altered by the addition of Cu. At the same time, most of the Cu atoms are not incorporated into the wurtzite lattice but rather have a CuO-like coordination. These results indicate that ferromagnetism of the investigated Zn1−xCuxO films is not directly linked to the doping atoms but rather is due to some other changes which have been introduced to the host ZnO by the dopants.

We report the results of our studies on the tailored magnetoelectric response of a polymer based nanocomposite system comprising of varying SmFeO3 filler volume percentage embedded in a poly(vinylidene fluoride) (PVDF) matrix. The ME induced voltage was observed to increase with an increase in the SmFeO3 filler concentration from 1% to 20%. For composite films with 20% SmFeO3 concentration an induced voltage of ∼5.2 mV cm−1 Oe−1 was obtained at 1 kHz. Such a large magnetoelectric response is attributed to intensive interfacial interaction caused by dense packing of magnetostrictive SmFeO3 in the piezoelectric matrix of PVDF. Further, poling of composite films by application of an electric field was observed to lead to a saturated magnetization hysteresis loop caused by reorientation of the magnetization of SmFeO3. This electric field mediated manipulation of magnetic properties in SmFeO3/PVDF holds great potential for low-energy-consuming spintronics devices.

Applied physics letters 117(1), 012901 (2020). doi:10.1063/5.0004785, Fe doping into BaTiO$_3$ stabilizes the paraelectric hexagonal phase in place of the ferroelectric tetragonal one. We show that simultaneous doping of Bi along with Fe into BaTiO$_3$ effectively enhances the magnetoelectric (ME) multiferroic response (both ferromagnetism and ferroelectricity) at room temperature, through careful tuning of Fe valency along with the controlled recovery of the ferroelectric-tetragonal phase. We also report a systematic increase in large dielectric constant values as well as reduction in loss tangent values with relatively moderate temperature variation of the dielectric constant around room temperature with increasing Bi doping content in Ba$_{1���x}$BixTi$_{0.90}$Fe$_{0.10}$O$_3$ (0 ��� x ��� 0.10), which makes the higher Bi���Fe codoped sample (x = 0.08) promising for use as a room-temperature high-�� dielectric material. Interestingly, the x = 0.08 (Bi���Fe codoped) sample is not only found to be ferroelectrically (���20 times) and ferromagnetically (���6 times) stronger than x = 0 (only Fe-doped) at room temperature, but also observed to be better insulating (larger bandgap) with indirect signatures of larger ME coupling as indicated from anomalous reduction of the magnetic coercive field with decreasing temperature. Thus, room-temperature ME multiferroicity has been engineered in Bi and Fe codoped BTO (BaTiO$_3$) compounds., Published by American Inst. of Physics, Melville, NY

In the present work, we have carried out a comparative study of the low temperature phase transitions using dc magnetization (M (T)) and ac susceptibility (χ (ω, T)) measurements on undoped and 0.3 wt% MnO2 doped BiFeO3 samples in the 2–300 K temperature range. It is shown that MnO2 doping increases the resistivity and decreases the dielectric loss as a result of reduced oxygen vacancy concentration as confirmed by iodometry and x-ray photoelectron spectroscopy (XPS) studies. A comparative study of the dc M (T) and ac χ (ω, T) results on two types of samples reveal that the transitions around 25 K, 110 to 150 K and 260 K are intrinsic to BiFeO3. The widely reported transition at 50 K is argued to be defect induced, as it is absent in the doped samples. We also show that the spin-glass transition temperature (TSG) ∼20 K, determined from an analysis of χ (ω, T), is less than the spin-glass freezing temperature (Tf) ∼25 K in marked contrast to TSG > Tf reported by earlier workers.

Cubic spinel CoCr2O4 has recently attained attention due to its multiferroic properties. However, the Co site substitution effect on the structural and magnetic properties has rarely been studied in thin film form. In this work, the structural and magnetic properties of Co1-x Ni x Cr2O4 (x= 0, 0.5) epitaxial thin films deposited on MgAl2O4 (100) and MgO (100) substrates to manipulate the nature of strain in the films using pulsed laser deposition (PLD) technique are presented. The epitaxial nature of the films was manifested through x-ray diffraction (XRD), reciprocal space mapping (RSM) and Rutherford backscattering spectrometry (RBS) measurements. Raman measurements revealed a disappearance of characteristic A 1g and F 2g modes of the CoCr2O4 with increase in the Ni content. Atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM) studies show a modification of the surface morphology upon Ni substitution. Magnetic measurements disclose that the ferrimagnetic Curie temperature (T C) of the CoCr2O4 in thin film grown on MgAl2O4 (100) and MgO (100) substrates were found to be 100.6 ± 0.5 K and 93.8 ± 0.2 K, respectively. With Ni substitution the T C values were found to be enhanced to 104.5 ± 0.4 K for MgAl2O4 (100) and 108.5 ± 0.6 K for MgO (100) substrates. X-ray photoelectron spectroscopy (XPS) suggests Cr3+ oxidation states in the films, while Co ions are present in a mixed Co2+/Co3+ oxidation state. The substitution of Ni at Co site significantly modifies the line shape of the core level as well as the valence band. Ni ions are also found to be in a mixed 2+/3+ oxidation state. O 1s core level display asymmetry related to possible defects like oxygen vacancies in the films.

Polyvinyl alcohol (PVA)–cobalt ferrite (CFO) nanocomposite films were synthesized by wet chemical method. The synthesized CFO nanomaterial was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), which confirm the formation of pure phase nanoparticles with cuboid shape. The variation in AC conductivity is measured as a function of frequency (within the range of 100 Hz–1 MHz) and temperature (from 303 to 403 K). It was observed that the frequency exponent, S, decreases with increasing temperature, which is explained by correlated barrier hopping (CBH) conduction mechanism. Frequency dependence of real and imaginary parts of the dielectric permittivity of PVA–CFO nanocomposite films for different temperatures is studied on the basis of the modified Cole–Cole model. The dielectric permittivity of the samples reveals an increasing tendency with the concentration of CFO filler in PVA matrix. A high value of 89 emu $$\hbox {g}^{-1}$$ saturation magnetization and 652 Oe coercivity are observed in CFO nanoparticle. The coercivity increased in PVA–CFO nanocomposite when compared to CFO nanoparticle, which is expected due to inverse magnetostrictive effect. The increasing tendency of dielectric constant and magnetization of the nanocomposites with the increasing CFO concentration enhances the potential of applications in miniaturization of the antenna system and electromagnetic shielding materials.

We observed enhanced field emission (FE) behavior for spitzer shaped ZnO nanowires synthesized via a hydrothermal approach. The spitzer shaped and pointed tipped 1D ZnO nanowires of average diameter 120 nm and length ∼5–6 μm were randomly grown over an ITO coated glass substrate. The turn-on field (Eon) of 1.56 V μm−1 required to draw a current density of 10 μA cm−2 from these spitzer shaped ZnO nanowires is significantly lower than that of pristine and doped ZnO nanostructures, and MoS2@TiO2 heterostructure based FE devices. The orthodoxy test that was performed confirms the feasibility of a field enhancement factor (βFE) of 3924 for ZnO/ITO emitters. The enhancement in FE behavior can be attributed to the spitzer shaped nanotips, sharply pointed nanotips and individual dispersion of the ZnO nanowires. The ZnO/ITO emitters exhibited very stable electron emission with average current fluctuations of ±5%. Our investigations suggest that the spitzer shaped ZnO nanowires have potential for further improving in electron emission and other functionalities after forming tunable nano-hetero-architectures with metal or conducting materials.

We report, the studies on the electronic structure and valence band modifications in sol–gel grown Zn1−xCoxO (x = 0, 0.5 and 0.15) samples, obtained using X-ray photoelectron spectroscopy (XPS) measurements. Structural studies confirm the single phasic hexagonal wurtzite structure having space group P63mc. XPS measurements of Co 2p core level indicate that, Co-ions are in +2 state in ZnO. Using valence band spectroscopy (VBS) and resonant photoemission spectroscopy (RPES) measurements, modifications in the electronic structure of Co-doped ZnO have been understood in the context of increment in the occupation of Co-3d states with Co-content which extends the VB maxima edge.

We have prepared 4 at.% Fe doped TiO2 thin films on LAO (001) and Si (111) substrates by pulsed laser deposition. X-ray diffraction (XRD) studies suggest different structural properties of the films on the different substrates. Raman measurements corroborate the XRD findings. The thicknesses of the films are also different on the two substrates, suggesting different nucleation process on the two substrates. Interestingly on both the substrates, Fe is not in metal clusters, suggesting their possible incorporation in TiO2 matrix. Copyright © 2011 VBRI press.

The self-assembled growth of vertically aligned nanostructures of BaTiO3 in the matrix of Fe2O3 is described. The arrays of well controlled and systematically ordered nanostructures of composite phases were grown on MgO and SrTiO3 single crystalline substrate by using the pulse laser deposition technique under optimized conditions. The phase purities of the composite structures were characterized by using x-ray diffraction and Raman spectroscopy. The surface topographical and morphological measurements were carried out for confirming the growth on nanostructures in the composite thin films. The ferroelectric properties of these composite films were probed by electrical polarization versus electric field (P-E) measurements. The electronic and magnetic properties of the composite were studied by employing x-ray absorption spectroscopy and magnetization measurements. The presence of strain state in nanostructures is found to play an important role in modifying the crystal field effects as well as the magnetic properties of the composite compound. It is shown that the vertical self-assembly of nanorods of BaTiO3 can be grown in the matrix layer of Fe2O3 on the MgO substrate by coablation.The self-assembled growth of vertically aligned nanostructures of BaTiO3 in the matrix of Fe2O3 is described. The arrays of well controlled and systematically ordered nanostructures of composite phases were grown on MgO and SrTiO3 single crystalline substrate by using the pulse laser deposition technique under optimized conditions. The phase purities of the composite structures were characterized by using x-ray diffraction and Raman spectroscopy. The surface topographical and morphological measurements were carried out for confirming the growth on nanostructures in the composite thin films. The ferroelectric properties of these composite films were probed by electrical polarization versus electric field (P-E) measurements. The electronic and magnetic properties of the composite were studied by employing x-ray absorption spectroscopy and magnetization measurements. The presence of strain state in nanostructures is found to play an important role in modifying the crystal field effects as well as the magneti...

Magnetic and dielectric studies of SrCu3Ti4O12 carried out over 5-300K confirm antiferromagnetic (AFM) ordering of Cu-spins at TN =23K. Dielectric constant {\epsilon}' measured across 1Hz-1MHz signifies quantum paraelectric character, Barrett-fittable almost down to TN. Competition of athermal fluctuations and the literature-reported magneto-phonon-softening near TN manifests a maiden quantum paraelectric glass (QPG) state. Emergent AFM-field tunes the otherwise quantum ordering (at absolute-zero) of the dipoles to finite-temperature kinetic glass transition; spectral dispersion of dielectric constant unambiguously manifested and characterized. Vogel-Fulcher glass-kinetics parameterization sets the almost relaxation-free QPG state in SrCu3Ti4O12 apart from an emergent scaling-class, to which typical ferroelectric relaxors belong., Comment: 15 pages, 42 references, 1 table, 6 figures

Ferromagnetism is observed at and above room temperature in pulsed laser deposited epitaxial films of Co-doped Ti-based oxide perovskite (La1-xSrxTiO3-d). The system has the characteristics of an intrinsic diluted magnetic semiconductor (metal) at low concentrations (

The electronic and magnetic properties of TiO$_2$, TiO$_{1.75}$, TiO$_{1.75}$N$_{0.25}$, and TiO$_{1.75}$F$_{0.25}$ compounds have been studied by using \emph{ab initio} electronic structure calculations. TiO$_2$ is found to evolve from a wide-band-gap semiconductor to a narrow-band-gap semiconductor to a half-metallic state and finally to a metallic state with oxygen vacancy, N-doping and F-doping, respectively. Present work clearly shows the robust magnetic ground state for N- and F-doped TiO$_2$. The N-doping gives rise to magnetic moment of $\sim$0.4 $\mu_B$ at N-site and $\sim$0.1 $\mu_B$ each at two neighboring O-sites, whereas F-doping creates a magnetic moment of $\sim$0.3 $\mu_B$ at the nearest Ti atom. Here we also discuss the possible cause of the observed magnetic states in terms of the spatial electronic charge distribution of Ti, N and F atoms responsible for bond formation., Comment: 11 pages, 4 figures To appear J. Phys.: Condens. Matter

The electronic structure of pulsed laser deposited Mo1-xFexO2 (x=0, 0.02 and 0.05) thin films has been investigated using resonant photoemission spectroscopy near Mo-4p absorption edge. In all the samples a broad Fano- like resonance peak at ~46 eV is observed in the whole area of the valence band which indicates the contribution of the Mo-4d states in the entire valence band region. The doping of Fe in these films leads to decrease in Mo 4d states contributing to electronic states at lower binding energy region. In addition to this, we also observe a shoulder at 4.9 eV in the valence band spectra of doped samples. It is proposed that the origin of this shoulder is due to the Fe hybridised states., Comment: 16 pages, 4 figures ,. J. Phys. Cond. Mat. (accepted)

A set of r.f. sputter deposited ZnO thin films prepared with different Mn doping concentrations have been characterised by Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Spectroscopy (XANES) measurements at Zn, Mn and O K edges and at Mn L2,3 edges apart from long range structural characterisation by Grazing Incident X-ray Diffraction (GIXRD) technique. Magnetic measurements show room temperature ferromagnetism in samples with lower Mn doping which is however, gets destroyed at higher Mn doping concentration. The results of the magnetic measurements have been explained using the local structure information obtained from EXAFS and XANES measurements.

Hole conducting, optically transparent Cu2O thin films on glass substrates have been synthesized by vacuum annealing (5�10-6 mbar at 700 K for 1 hour) of magnetron sputtered (at 300 K) CuO thin films. The Cu2O thin films are p-type and show enhanced properties: grain size (54.7 nm), optical transmission 72% (at 600 nm) and Hall mobility 51 cm2/Vs. The bulk and surface Valence band spectra of Cu2O and CuO thin films are studied by temperature dependent Hall effect and Ultra violet photo electron Spectroscopy (UPS). CuO thin films show a significant band bending downwards (due to higher hole concentration) than Cu2O thin films. � 2015 Author(s).

We have studied magnetic behaviour of pulsed laser grown epitaxial thin film of layered compound Sr1.5Pr0.5CoO4 (SPCO) on LaAlO3 [001] substrate. Co-2p core level x-ray photoemission spectra mimics the mixed valence state of Co in the grown film. Arrot plots analysis implies that the magnetization of the system obeys mean field type behavior. Our study suggests that the low temperature magnetic behavior of SPCO can be classified as anisotropic ferromagnetic state, manifested through the analysis of thermo-magnetic irreversibility and cusp in ZFC magnetization (M–T) as well as absence of zero field cooled memory effect. In addition, our study confirms that there is no exchange bias effect in the material. Time dependence of the magnetization relaxation behavior reveals the existence of multiple metastable magnetic states in the system. Slow relaxation of magnetization and aging effect are found to be described by a hierarchical model.

Thin films of magnetite (Fe3O4) are grown on single crystal GaAs (100) substrate by pulsed laser deposition. X ray diffraction (XRD) result shows the (111) preferred orientation of the Fe3O4 film and x-ray photoelectron spectroscopy confirm the presence of single phase Fe3O4 in the film. The electrical transport property of the film shows the characteristic Verwey transition at 122 K and below 110 K, the transport follows variable range hopping type conduction mechanism. The film shows room temperature magnetization hysteresis loop suggesting the ferrimagnetic behavior of the film with saturation magnetization value close to 470 emu/cc., 16 pages, 5 figurs