B. Krichevtsov - Academia.edu (original) (raw)

Papers by B. Krichevtsov

Research paper thumbnail of Antiferromagnetic and ferromagnetic Faraday effect in yttrium orthoferrite YFeO3

Research paper thumbnail of Cobalt epitaxial nanoparticles on CaF2/Si(111): Growth process, morphology, crystal structure, and magnetic properties

Physical Review B, 2013

We study molecular beam epitaxy growth, morphology, crystal structure, and magnetic properties of... more We study molecular beam epitaxy growth, morphology, crystal structure, and magnetic properties of Co nanoislands on CaF 2 /Si(111) surface. In order to have a full appreciation of complex growth kinetics at different stages, a comprehensive study of Co growth on CaF 2 is carried out by atomic force, scanning electron, and transmission electron microscopies in the direct space, as well as by x-ray and electron diffraction in the reciprocal space. These experimental data are complemented by theoretical modeling. Magnetic properties are characterized by magneto-optical Kerr effect and superconducting quantum interference device magnetometries. Key effects influencing the Co growth on fluorite are addressed, including the sticking probability, the preferential nucleation sites, the size and shape time evolution, the dependence of Co morphology on temperature and Co exposure, and the coalescence mechanism. The two-stage deposition technique is developed, whereby the low-temperature seeding stage is used to facilitate Co nucleation, and the follow-up high-temperature deposition yields Co particles with high crystalline quality. Our results enable precise control over the resulting morphology, spatial ordering, and crystal structure affecting the magnetic properties. In particular, it is demonstrated that the transformation from dense to isolated Co nanoparticles leads to the change of the in-plane and out-of-plane magnetic anisotropy and also the sign of polar and longitudinal magneto-optical Kerr effects.

Research paper thumbnail of Local field effects in magneto-optics of two-dimensional arrays of ferromagnetic nanoparticles

Physics of the Solid State, 2010

ABSTRACT A theory of the polar magneto-optical Kerr effect in a layer of small ferromagnetic part... more ABSTRACT A theory of the polar magneto-optical Kerr effect in a layer of small ferromagnetic particles has been developed in the framework of the Green’s function method of electrodynamics. The manifestation in magneto-optics of the local field effect, which is initiated by the contribution to the effective field of dipole moments induced in particles, has been studied in terms of the model of a square lattice of ferromagnetic ellipsoids. The magneto-optical Kerr effect stimulated under normal incidence of a linearly polarized electromagnetic wave on a layer of particles magnetized perpendicular to the layer plane has been analyzed. The dependence of the Kerr rotation angle in an array of ellipsoidal Co particles embedded in the transparent dielectric CaF2 on the light frequency, the parameters of the ellipsoidal particles, and the lattice period (concentration of the magnet in the layer) has been studied numerically. It has been shown that, within a broad (2.0–4.5 eV) spectral range, the local field effect studied as a function of increasing concentration of Co particles in the layer manifests itself in the reversal of the sign of the Kerr rotation compared to that observed in a single ellipsoid or a solid Co film.

Research paper thumbnail of Small- and strong-signal dielectric response in a single-crystal film of partially deuterated betaine phosphite

Physics of the Solid State, 2011

ABSTRACT Poly- and single-crystal films of betaine phosphite deuterated to ∼20% have been grown b... more ABSTRACT Poly- and single-crystal films of betaine phosphite deuterated to ∼20% have been grown by evaporation on NdGaO3 (001) substrates with a preliminarily deposited planar interdigital structure of electrodes. The small-signal dielectric response in the 0.1–100.0-kHz frequency range has revealed a strong anomaly in capacitance upon the transition of the films to the ferroelectric state. Application of a bias field brings about suppression and a slight shift of the dielectric anomaly toward higher temperatures. The strong-signal dielectric response has been studied by the Sawyer-Tower method over the frequency range 0.06–3.00 kHz both in the para- and ferroelectric phases. In contrast to the case of a plane-parallel capacitor, in the planar structure studied, the dielectric hysteresis loops exhibit a very small coercivity at low frequencies, which grows with increasing frequency. This difference should be assigned to different domain structures formed in a planeparallel capacitor and in a planar structure in a saturating field. The growth of hysteresis with increasing frequency in a planar structure is considered to be associated with the domain wall motion.

Research paper thumbnail of Reciprocal and Non-Reciprocal Linear Magnetic Birefringence in Magnetic Semiconductor γ-Dy2S3

Magnetoelectric Interaction Phenomena in Crystals, 2004

In cubic magnetic semiconductor γ — Dy 2 S 3 the anisotropy and dispersion of Cotton-Mouton effec... more In cubic magnetic semiconductor γ — Dy 2 S 3 the anisotropy and dispersion of Cotton-Mouton effect (CME) and non-reciprocal linear birefringence (NB) have been studied. The anisotropy of NB at photon energies E <2 eV corresponds to manifestation of second-order magneto-electric susceptibility in optical region. The dispersion of NB in γ— Dy 2 S 3 is of the same type that is known for crystals of Cd 1-x Mn x Te family. This indicates the impact of inversion asymmetry on the conduction band. The anisotropy of CME in transparent region and in the region of local electronic transition 6 H 15/2 →6F 3/2 shows the existence of strong axial crystal field in positions of rare-earth ion.

Research paper thumbnail of Magnetoelectric Spectroscopy of Electronic Transitions in Antiferromagnetic Cr2O3

Physical Review Letters, 1996

Research paper thumbnail of Magnetic circular dichroism in YBa 2 Cu 3 O 7-δ and estimate of the nonreciprocal optical effects predicted by the anyon model of high-T c superconductivity

Research paper thumbnail of Laser MBE-grown CoFeB epitaxial layers on MgO: Surface morphology, crystal structure, and magnetic properties

Physical Review Materials

Epitaxial layers of CoFeB were grown on MgO by means of laser molecular beam epitaxy using Co 40 ... more Epitaxial layers of CoFeB were grown on MgO by means of laser molecular beam epitaxy using Co 40 Fe 40 B 20 target. The growth was combined with in situ structural characterization by three-dimensional reciprocal space mapping obtained from reflection high energy electron diffraction (RHEED) data. High-temperature single stage growth regime was adopted to fabricate CoFeB layers. As confirmed by the atomic force microscopy, the surface of CoFeB layers consists of closely spaced nanometer sized islands with dimensions dependent on the growth temperature. As shown by RHEED and XRD analysis, the CoFeB layers grown at high-temperature on MgO(001) possess body centered cubic (bcc) crystal structure with the lattice constant a = 2.87Å close to that of the Co 75 Fe 25 alloy. It was further shown that following the same high-temperature growth technique the MgO/CoFeB/MgO(001) heterostructures can be fabricated with top and bottom MgO layers of the same crystallographic orientation. The CoFeB layers were also grown on the GaN(0001) substrates using MgO(111) as a buffer layer. In this case, the CoFeB layers crystallize in bcc crystal structure with the (111) axis perpendicular to the substrate surface. The magnetic properties of the CoFeB/MgO (001) heterostructures have been investigated by measuring magnetization curves with a vibrating sample magnetometer as well as by performing magneto-optical Kerr effect (MOKE) and ferromagnetic resonance (FMR) studies. FMR spectra were obtained for the variety of the magnetic field directions and typically consisted of a single relatively narrow resonance line. The magnetization orientations and the resonance conditions were calculated in the framework of a standard magnetic energy minimization procedure involving a single K 1c cubic term for the magnetocrystalline anisotropy. This allows a fairly accurate description of the angular dependences of the resonance fields-both in-plane and out-of-plane. It was shown that CoFeB layers exhibit in-plane fourth-order magnetic anisotropy. A two-step magnetization reversal model has been adopted for the CoFeB layers based on the VSM measurement analysis. Magnetization reversal studies performed by polar MOKE indicate that the magnetization lies in-plane in absence of magnetic field. Observed magnetic field dependences of reflected light ellipticity in geometry of longitudinal Kerr effect give convincing evidence for contribution of quadratic in magnetization terms in the dielectric tensor and clearly show the in-plane magnetization rotation.

Research paper thumbnail of Magnetization reversal in NiFe2O4/SrTiO3 nanoheterostructures grown by laser molecular beam epitaxy

Journal of Physics: Conference Series

Research paper thumbnail of Crystal Structure, Raman Spectroscopy and Dielectric Properties of New Semiorganic Crystals Based on 2-Methylbenzimidazole

Crystals

New single crystals, based on 2-methylbenzimidazole (MBI), of MBI-phosphite (C16H24N4O7P2), MBI-p... more New single crystals, based on 2-methylbenzimidazole (MBI), of MBI-phosphite (C16H24N4O7P2), MBI-phosphate-1 (C16H24N4O9P2), and MBI-phosphate-2 (C8H16N2O9P2) were obtained by slow evaporation method from a mixture of alcohol solution of MBI crystals and water solution of phosphorous or phosphoric acids. Crystal structures and chemical compositions were determined by single crystal X-ray diffraction (XRD) analysis and confirmed by XRD of powders and elemental analysis. Raman spectroscopy of new crystals evidences the presence in crystals of MBI-, H3PO3-, or H3PO4- and water molecules. Dielectric properties of crystals reveal strong increase and low frequency dispersion of dielectric constant and losses at heating, indicating the appearance of proton conductivity. At low temperatures in MBI-phosphate-2, an increase of dielectric constant analogous to quantum paraelectric state is observed.

Research paper thumbnail of Elastic and Piezoelectric Parameters of the Crystals of Histidine Phosphite L-Hist · H3РО3 Measured by the Method of Electromechanical Resonance

Technical Physics Letters

Research paper thumbnail of Polarization switching, dielectric, structural and elastic properties of 2-Methylbenzimidazole crystals and films

Research paper thumbnail of Thin yttrium iron garnet films grown by pulsed laser deposition: Crystal structure, static, and dynamic magnetic properties

Journal of Applied Physics

Research paper thumbnail of Growth of Y3Fe5O12/GaN layers by laser molecular-beam epitaxy and characterization of their structural and magnetic properties

Technical Physics Letters

Research paper thumbnail of Dielectric properties of ferroelectric betaine phosphite crystals with a high degree of deuteration

Physics of the Solid State

Research paper thumbnail of Effect of thermal annealing on the electromagnetooptic effect in epitaxial films of iron garnets

Journal of Optical Technology, 1999

Research paper thumbnail of Dielectric properties of thin films of partially deuterated betaine phosphite with large- and small-block structures

Physics of the Solid State, 2014

Research paper thumbnail of Imprinted Magnetic Anisotropy and Zigzag Domain Structure of Amorphous TbCo Films

Journal of Superconductivity and Novel Magnetism, 2015

We investigate the magnetic anisotropy and domain structure of amorphous Tb x Co (1−x) films grow... more We investigate the magnetic anisotropy and domain structure of amorphous Tb x Co (1−x) films grown in external in-plane magnetic field by high-frequency ion sputtering. Films with different thicknesses 100 and 500 nm and rare-earth element concentrations x = 12 % and x = 34 % present strong imprinted in-plane uniaxial anisotropy. Measurements of magnetic properties and domain structure imaging were performed by means of longitudinal and polar magneto-optical Kerr effect (MOKE). The coercivity fields increase by an order of magnitude for the higher Tb V. Ukleev

Research paper thumbnail of Dielectric and structural properties of ferroelectric betaine arsenate films

Physics of the Solid State, 2014

ABSTRACT Ferroelectric films of betaine arsenate and partially deuterated betaine arsenate have b... more ABSTRACT Ferroelectric films of betaine arsenate and partially deuterated betaine arsenate have been grown by evaporation on LiNbO3, α-Al2O3, and NdGaO3 substrates with a preliminarily deposited structure of interdigitated electrodes, as well as on the Al/glass substrate. This paper presents the results of the examination of the block structure of the films in a polarizing microscope, the X-ray diffraction analysis of their crystal structure, and the investigation of the dielectric properties in a measuring field oriented both parallel and perpendicular to the plane of the film. The transition of the films to the ferroelectric state at T = T c is accompanied by anomalies of the capacitance of the structure, an increase in the dielectric loss, and the appearance of dielectric hysteresis loops. The growth of the films from a solution of betaine arsenate in a heavy water leads to an increase in the ferroelectric transition temperature from T c = 119 K in the films without deuterium to T c = 149 K, which corresponds to the degree of deuteration of approximately 60-70%. The dielectric and structural properties of the films are compared with those of the betaine arsenate single crystals and the previously studied films of betaine phosphite and glycine phosphite.

Research paper thumbnail of Electromagnetooptical Effects in Ferri-And Antiferromagnets

Journal of the Magnetics Society of Japan, 1987

Optical methods open new horizons in studying magnetoelectric interaction in magnetically ordered... more Optical methods open new horizons in studying magnetoelectric interaction in magnetically ordered crystals. In the present paper we shall report on some new optical effects observed in two model crystals: ~n antiferromagnetic Cr 2 0 and in ferrimagnetic Y~Fe~Ot2. In Cr70~ we observed a nonreciprocal rotation or ~lane-po larized light induced by ac eIeetric field applied along optical axis. The temperature variation of this rotation was found to differ substantially from that of magnetoelectric effect in a low-frequency range. New antiferromagnetic mechanism of nonreciprocal rotation was suggested to exist in an optical spectral range. In Cr ° a second order optical magnetoelectric effect was observed for the first tiffie 3 which was related to an antiferromagnetic domain switching. In Y,Fe 5 0 17 electromagnetooptical effects were observed mainly in the regions of domain waIl movement and rotation of magnetization. Much better resolution was obtained in comparison to a low-frequency study of magnetoelectric interaction. A forbidden, linear in electric field, effect was observed in Y,Fe~012 and we relate it to crystal imperfections, which destroy the symmetry center.

Research paper thumbnail of Antiferromagnetic and ferromagnetic Faraday effect in yttrium orthoferrite YFeO3

Research paper thumbnail of Cobalt epitaxial nanoparticles on CaF2/Si(111): Growth process, morphology, crystal structure, and magnetic properties

Physical Review B, 2013

We study molecular beam epitaxy growth, morphology, crystal structure, and magnetic properties of... more We study molecular beam epitaxy growth, morphology, crystal structure, and magnetic properties of Co nanoislands on CaF 2 /Si(111) surface. In order to have a full appreciation of complex growth kinetics at different stages, a comprehensive study of Co growth on CaF 2 is carried out by atomic force, scanning electron, and transmission electron microscopies in the direct space, as well as by x-ray and electron diffraction in the reciprocal space. These experimental data are complemented by theoretical modeling. Magnetic properties are characterized by magneto-optical Kerr effect and superconducting quantum interference device magnetometries. Key effects influencing the Co growth on fluorite are addressed, including the sticking probability, the preferential nucleation sites, the size and shape time evolution, the dependence of Co morphology on temperature and Co exposure, and the coalescence mechanism. The two-stage deposition technique is developed, whereby the low-temperature seeding stage is used to facilitate Co nucleation, and the follow-up high-temperature deposition yields Co particles with high crystalline quality. Our results enable precise control over the resulting morphology, spatial ordering, and crystal structure affecting the magnetic properties. In particular, it is demonstrated that the transformation from dense to isolated Co nanoparticles leads to the change of the in-plane and out-of-plane magnetic anisotropy and also the sign of polar and longitudinal magneto-optical Kerr effects.

Research paper thumbnail of Local field effects in magneto-optics of two-dimensional arrays of ferromagnetic nanoparticles

Physics of the Solid State, 2010

ABSTRACT A theory of the polar magneto-optical Kerr effect in a layer of small ferromagnetic part... more ABSTRACT A theory of the polar magneto-optical Kerr effect in a layer of small ferromagnetic particles has been developed in the framework of the Green’s function method of electrodynamics. The manifestation in magneto-optics of the local field effect, which is initiated by the contribution to the effective field of dipole moments induced in particles, has been studied in terms of the model of a square lattice of ferromagnetic ellipsoids. The magneto-optical Kerr effect stimulated under normal incidence of a linearly polarized electromagnetic wave on a layer of particles magnetized perpendicular to the layer plane has been analyzed. The dependence of the Kerr rotation angle in an array of ellipsoidal Co particles embedded in the transparent dielectric CaF2 on the light frequency, the parameters of the ellipsoidal particles, and the lattice period (concentration of the magnet in the layer) has been studied numerically. It has been shown that, within a broad (2.0–4.5 eV) spectral range, the local field effect studied as a function of increasing concentration of Co particles in the layer manifests itself in the reversal of the sign of the Kerr rotation compared to that observed in a single ellipsoid or a solid Co film.

Research paper thumbnail of Small- and strong-signal dielectric response in a single-crystal film of partially deuterated betaine phosphite

Physics of the Solid State, 2011

ABSTRACT Poly- and single-crystal films of betaine phosphite deuterated to ∼20% have been grown b... more ABSTRACT Poly- and single-crystal films of betaine phosphite deuterated to ∼20% have been grown by evaporation on NdGaO3 (001) substrates with a preliminarily deposited planar interdigital structure of electrodes. The small-signal dielectric response in the 0.1–100.0-kHz frequency range has revealed a strong anomaly in capacitance upon the transition of the films to the ferroelectric state. Application of a bias field brings about suppression and a slight shift of the dielectric anomaly toward higher temperatures. The strong-signal dielectric response has been studied by the Sawyer-Tower method over the frequency range 0.06–3.00 kHz both in the para- and ferroelectric phases. In contrast to the case of a plane-parallel capacitor, in the planar structure studied, the dielectric hysteresis loops exhibit a very small coercivity at low frequencies, which grows with increasing frequency. This difference should be assigned to different domain structures formed in a planeparallel capacitor and in a planar structure in a saturating field. The growth of hysteresis with increasing frequency in a planar structure is considered to be associated with the domain wall motion.

Research paper thumbnail of Reciprocal and Non-Reciprocal Linear Magnetic Birefringence in Magnetic Semiconductor γ-Dy2S3

Magnetoelectric Interaction Phenomena in Crystals, 2004

In cubic magnetic semiconductor γ — Dy 2 S 3 the anisotropy and dispersion of Cotton-Mouton effec... more In cubic magnetic semiconductor γ — Dy 2 S 3 the anisotropy and dispersion of Cotton-Mouton effect (CME) and non-reciprocal linear birefringence (NB) have been studied. The anisotropy of NB at photon energies E <2 eV corresponds to manifestation of second-order magneto-electric susceptibility in optical region. The dispersion of NB in γ— Dy 2 S 3 is of the same type that is known for crystals of Cd 1-x Mn x Te family. This indicates the impact of inversion asymmetry on the conduction band. The anisotropy of CME in transparent region and in the region of local electronic transition 6 H 15/2 →6F 3/2 shows the existence of strong axial crystal field in positions of rare-earth ion.

Research paper thumbnail of Magnetoelectric Spectroscopy of Electronic Transitions in Antiferromagnetic Cr2O3

Physical Review Letters, 1996

Research paper thumbnail of Magnetic circular dichroism in YBa 2 Cu 3 O 7-δ and estimate of the nonreciprocal optical effects predicted by the anyon model of high-T c superconductivity

Research paper thumbnail of Laser MBE-grown CoFeB epitaxial layers on MgO: Surface morphology, crystal structure, and magnetic properties

Physical Review Materials

Epitaxial layers of CoFeB were grown on MgO by means of laser molecular beam epitaxy using Co 40 ... more Epitaxial layers of CoFeB were grown on MgO by means of laser molecular beam epitaxy using Co 40 Fe 40 B 20 target. The growth was combined with in situ structural characterization by three-dimensional reciprocal space mapping obtained from reflection high energy electron diffraction (RHEED) data. High-temperature single stage growth regime was adopted to fabricate CoFeB layers. As confirmed by the atomic force microscopy, the surface of CoFeB layers consists of closely spaced nanometer sized islands with dimensions dependent on the growth temperature. As shown by RHEED and XRD analysis, the CoFeB layers grown at high-temperature on MgO(001) possess body centered cubic (bcc) crystal structure with the lattice constant a = 2.87Å close to that of the Co 75 Fe 25 alloy. It was further shown that following the same high-temperature growth technique the MgO/CoFeB/MgO(001) heterostructures can be fabricated with top and bottom MgO layers of the same crystallographic orientation. The CoFeB layers were also grown on the GaN(0001) substrates using MgO(111) as a buffer layer. In this case, the CoFeB layers crystallize in bcc crystal structure with the (111) axis perpendicular to the substrate surface. The magnetic properties of the CoFeB/MgO (001) heterostructures have been investigated by measuring magnetization curves with a vibrating sample magnetometer as well as by performing magneto-optical Kerr effect (MOKE) and ferromagnetic resonance (FMR) studies. FMR spectra were obtained for the variety of the magnetic field directions and typically consisted of a single relatively narrow resonance line. The magnetization orientations and the resonance conditions were calculated in the framework of a standard magnetic energy minimization procedure involving a single K 1c cubic term for the magnetocrystalline anisotropy. This allows a fairly accurate description of the angular dependences of the resonance fields-both in-plane and out-of-plane. It was shown that CoFeB layers exhibit in-plane fourth-order magnetic anisotropy. A two-step magnetization reversal model has been adopted for the CoFeB layers based on the VSM measurement analysis. Magnetization reversal studies performed by polar MOKE indicate that the magnetization lies in-plane in absence of magnetic field. Observed magnetic field dependences of reflected light ellipticity in geometry of longitudinal Kerr effect give convincing evidence for contribution of quadratic in magnetization terms in the dielectric tensor and clearly show the in-plane magnetization rotation.

Research paper thumbnail of Magnetization reversal in NiFe2O4/SrTiO3 nanoheterostructures grown by laser molecular beam epitaxy

Journal of Physics: Conference Series

Research paper thumbnail of Crystal Structure, Raman Spectroscopy and Dielectric Properties of New Semiorganic Crystals Based on 2-Methylbenzimidazole

Crystals

New single crystals, based on 2-methylbenzimidazole (MBI), of MBI-phosphite (C16H24N4O7P2), MBI-p... more New single crystals, based on 2-methylbenzimidazole (MBI), of MBI-phosphite (C16H24N4O7P2), MBI-phosphate-1 (C16H24N4O9P2), and MBI-phosphate-2 (C8H16N2O9P2) were obtained by slow evaporation method from a mixture of alcohol solution of MBI crystals and water solution of phosphorous or phosphoric acids. Crystal structures and chemical compositions were determined by single crystal X-ray diffraction (XRD) analysis and confirmed by XRD of powders and elemental analysis. Raman spectroscopy of new crystals evidences the presence in crystals of MBI-, H3PO3-, or H3PO4- and water molecules. Dielectric properties of crystals reveal strong increase and low frequency dispersion of dielectric constant and losses at heating, indicating the appearance of proton conductivity. At low temperatures in MBI-phosphate-2, an increase of dielectric constant analogous to quantum paraelectric state is observed.

Research paper thumbnail of Elastic and Piezoelectric Parameters of the Crystals of Histidine Phosphite L-Hist · H3РО3 Measured by the Method of Electromechanical Resonance

Technical Physics Letters

Research paper thumbnail of Polarization switching, dielectric, structural and elastic properties of 2-Methylbenzimidazole crystals and films

Research paper thumbnail of Thin yttrium iron garnet films grown by pulsed laser deposition: Crystal structure, static, and dynamic magnetic properties

Journal of Applied Physics

Research paper thumbnail of Growth of Y3Fe5O12/GaN layers by laser molecular-beam epitaxy and characterization of their structural and magnetic properties

Technical Physics Letters

Research paper thumbnail of Dielectric properties of ferroelectric betaine phosphite crystals with a high degree of deuteration

Physics of the Solid State

Research paper thumbnail of Effect of thermal annealing on the electromagnetooptic effect in epitaxial films of iron garnets

Journal of Optical Technology, 1999

Research paper thumbnail of Dielectric properties of thin films of partially deuterated betaine phosphite with large- and small-block structures

Physics of the Solid State, 2014

Research paper thumbnail of Imprinted Magnetic Anisotropy and Zigzag Domain Structure of Amorphous TbCo Films

Journal of Superconductivity and Novel Magnetism, 2015

We investigate the magnetic anisotropy and domain structure of amorphous Tb x Co (1−x) films grow... more We investigate the magnetic anisotropy and domain structure of amorphous Tb x Co (1−x) films grown in external in-plane magnetic field by high-frequency ion sputtering. Films with different thicknesses 100 and 500 nm and rare-earth element concentrations x = 12 % and x = 34 % present strong imprinted in-plane uniaxial anisotropy. Measurements of magnetic properties and domain structure imaging were performed by means of longitudinal and polar magneto-optical Kerr effect (MOKE). The coercivity fields increase by an order of magnitude for the higher Tb V. Ukleev

Research paper thumbnail of Dielectric and structural properties of ferroelectric betaine arsenate films

Physics of the Solid State, 2014

ABSTRACT Ferroelectric films of betaine arsenate and partially deuterated betaine arsenate have b... more ABSTRACT Ferroelectric films of betaine arsenate and partially deuterated betaine arsenate have been grown by evaporation on LiNbO3, α-Al2O3, and NdGaO3 substrates with a preliminarily deposited structure of interdigitated electrodes, as well as on the Al/glass substrate. This paper presents the results of the examination of the block structure of the films in a polarizing microscope, the X-ray diffraction analysis of their crystal structure, and the investigation of the dielectric properties in a measuring field oriented both parallel and perpendicular to the plane of the film. The transition of the films to the ferroelectric state at T = T c is accompanied by anomalies of the capacitance of the structure, an increase in the dielectric loss, and the appearance of dielectric hysteresis loops. The growth of the films from a solution of betaine arsenate in a heavy water leads to an increase in the ferroelectric transition temperature from T c = 119 K in the films without deuterium to T c = 149 K, which corresponds to the degree of deuteration of approximately 60-70%. The dielectric and structural properties of the films are compared with those of the betaine arsenate single crystals and the previously studied films of betaine phosphite and glycine phosphite.

Research paper thumbnail of Electromagnetooptical Effects in Ferri-And Antiferromagnets

Journal of the Magnetics Society of Japan, 1987

Optical methods open new horizons in studying magnetoelectric interaction in magnetically ordered... more Optical methods open new horizons in studying magnetoelectric interaction in magnetically ordered crystals. In the present paper we shall report on some new optical effects observed in two model crystals: ~n antiferromagnetic Cr 2 0 and in ferrimagnetic Y~Fe~Ot2. In Cr70~ we observed a nonreciprocal rotation or ~lane-po larized light induced by ac eIeetric field applied along optical axis. The temperature variation of this rotation was found to differ substantially from that of magnetoelectric effect in a low-frequency range. New antiferromagnetic mechanism of nonreciprocal rotation was suggested to exist in an optical spectral range. In Cr ° a second order optical magnetoelectric effect was observed for the first tiffie 3 which was related to an antiferromagnetic domain switching. In Y,Fe 5 0 17 electromagnetooptical effects were observed mainly in the regions of domain waIl movement and rotation of magnetization. Much better resolution was obtained in comparison to a low-frequency study of magnetoelectric interaction. A forbidden, linear in electric field, effect was observed in Y,Fe~012 and we relate it to crystal imperfections, which destroy the symmetry center.