共查询到20条相似文献,搜索用时 671 毫秒
1.
The specific features of the antiferromagnetic domain structure, magnetization, and polarization induced by an inhomogeneous micromagnetic distribution in films of bismuth ferrite multiferroics have been investigated. It has been shown that the magnetic domain structure correlates with the ferroelectric domain structure, and the character of the rotation of the antiferromagnetic vector depends on the type of ferroelectric domain walls. An asymmetry in the distribution of the antiferromagnetic vector has been observed for the cases of 109° and 71° ferroelectric domain walls. It has been demonstrated that there are differences in the distributions of the polarization and magnetization in bismuth ferrite films with ferroelectric domains separated by 109° and 71° walls. The basic mechanisms responsible for the magnetization in domain walls in multiferroics have been considered. 相似文献
2.
S.K. Pradhan P.P. Rout D.K. Mishra A.K. Pradhan B.B. Nayak B.K. Roul 《Journal of magnetism and magnetic materials》2010,322(22):3614-3622
This paper reports that defect driven magnetism can be obtained at room temperature by optimizing metal ion concentration in bismuth ferrite (BFO) following our novel slow step solid state sintering route. We observed a clean signature of enhanced multiferroic behavior in Gd doped bismuth ferrite (Gd-BFO) bulk ceramics at room temperature (RT). Bismuth rich iron deficient Gd-BFO ceramics were prepared by solid state route through slow step sintering schedule at 850 °C. At particular composition, (Bi1.2Gd0.1Fe0.8O3), this materials completely transform from rhombohedral R3c to orthorhombic Pn21a space group. We emphasized that excess bismuth is expected to act as point defects and occupy interstitials positions, which in turn interact by oxygen vacancies. These defects are likely to promote defect driven ferromagnetism in BFO system. Incorporation of Gd in presence of excess bismuth in BFO enhanced both spin and electric polarization at room temperature. We also infer that Gd substitution in BFO is likely to suppress spiral spin modulation, which also favors ferromagnetism in Gd-BFO. 相似文献
3.
E. D. Mishina S. V. Semin K. V. Shvyrkov A. V. Kudryavtsev N. A. Il’in N. E. Sherstyuk V. M. Mukhortov 《Physics of the Solid State》2012,54(5):887-893
The specific features of the application of two-photon microscopy and spectroscopy to the investigation of multiferroic and piezoelectric nanostructures have been considered. It has been shown that the nonlinear optical response of planar multilayer barium strontium titanate/bismuth ferrite nanostructures is characterized by local electrically induced and magnetically induced contributions in specific spectral ranges. For peptide piezoelectric bio-microtubes, it has been found that the maximum value of the second harmonic generation intensity does not change along the tube, whereas the direction of polarization changes significantly. 相似文献
4.
S. A. Sadykov D. K. Palchaev Zh. Kh. Murlieva M. Kh. Rabadanov N. M.-R. Alikhanov V. V. Samsonova S. N. Kallaev Z. M. Omarov R. M. Emirov A. Kh. D. Khashafa 《Physics of the Solid State》2016,58(5):959-966
This paper presents the results of an investigation of changes in the structure, magnetic, electrical, and thermal properties of a nanostructured bismuth ferrite powder prepared by the combustion of nitrateorganic precursors before and after heat treatment at temperatures of 500, 600, 700, and 800°C. It has been shown that there is a dependence of the magnetic properties on the dispersion of the particles. The specific features of the temperature and frequency dependences of the dielectric properties over wide ranges of frequencies and temperatures, as well as near the Néel temperature, have been considered. 相似文献
5.
The value of the exchange coupling between a Co0.9Fe0.1 nanolayer and a bismuth ferrite multiferroic (BiFeO3) nanolayer has been calculated. Two possible variants of matching of the layer crystal structures are proposed. The interaction energy of the layers is shown to be sufficient to record information in the Co0.9Fe0.1 layer that enters in the composition of the magnetic tunnel junction by applying an electric field to the bismuth ferrite layer. 相似文献
6.
S. Díaz-Castañón O. García-Zaldívar J. Faloh-Gandarilla B. E. Watts F. Calderón-Piñar M. A. Hernández-Landaverde F. J. Espinoza-Beltran 《Applied Physics A: Materials Science & Processing》2014,117(3):1283-1288
Metalorganic decomposition and coprecipitation from aqueous solution have been used to synthesize thin film and bulk bismuth ferrite (BiFeO3) with perovskite structure. X-ray diffraction, thermomagnetic analysis, and scanning electron microscopy were used to analyze the material and identify spurious phases. The magnetic characterization at room temperature revealed remarkable differences between bulk and film samples. The results show that in BiFeO3 bulk ceramics, spontaneous magnetization is not observed at room temperature. Nevertheless, in thin films, a well-defined ferromagnetic behavior is observed at room temperature. Dielectric measurements taken on ceramic samples present an anomaly around 643 K that can be associated with the Néel temperature. 相似文献
7.
Magnetic bioceramics based on hydroxyapatite Ca5(PO4)3OH and particles of the M-type hexagonal (barium or calcium) ferrite with a high bioactivity and magnetic characteristics
providing hyperthermal treatment of oncology diseases has been developed and studied. The phase composition, microstructure,
and magnetic properties of the synthesized bioceramics have been determined. It has been shown that the synthesized biomaterial
consists of the biocompatible matrix with the apatite structure into which particles of hexagonal ferrite are incorporated.
The magnetic parameters of the synthesized ceramics are substantially higher than those of the bioglass ceramics modified
by iron oxides that have been used in medicine, which suggests good potential and effectiveness of application of the created
ceramics for medical purposes. Thus, a new class of magnetic bioceramics combining hydroxyapatite Ca5(PO4)3OH, which exhibits good properties in biocompatibility and bioactivity, with particles of the M-type hexagonal ferrite, which
possess high magnetic characteristics, has been created. 相似文献
8.
A double perovskite sample of (Ca, Ce) modified bismuth ferrite (i.e., BiCaFeCeO6) has been synthesized by a solid state reaction method. A single-phase characteristic of the material was carried out by analyzing basic X-ray crystal structure. The micrograph of the sintered sample was recorded at room temperature by using scanning electron microscope. The image of the micrograph shows the homogeneous distribution of with different grain size and shape. It shows that a high-density sample can be fabricated in the above experimental condition. This prepared complex electronic system (BiCaFeCeO6) exhibits multiferroic characteristics that has experimentally been supported by detailed analysis of capacitive, impedance, magnetic and other related behavior of the material Attempts have been made to study the (a) effect of microstructures containing grains, grain boundaries and electrodes in impedance and capacitive characteristics, (b) relationship between properties and crystal structure and (c) nature of relaxation mechanism of the prepared samples. Detailed impedance analysis with experimental data, collected at different frequency (103–106 Hz) and temperatures, has provided many important characteristics of the material. The variation of conductivity in alternating current of the material at different temperatures follows Jonsher's universal power law. Some multiferroic characteristics (dielectric constant, tangent loss, conductivity, magneto-electric) of bismuth ferrite have been tailored (decrease/increase) by multiple doping of (Ca, Ce) which will be useful to explore the possibility for applications. 相似文献
9.
10.
11.
N. é. Sherstyuk N. A. Il’in S. V. Semin E. D. Mishina V. M. Mukhortov 《Physics of the Solid State》2009,51(7):1356-1359
The specific features of the ferroelectric polarization switching in bismuth ferrite thin films doped with neodymium ions are investigated by the optical second harmonic generation technique. The structure and nonlinear optical properties of the samples prepared are studied in the course of ferroelectric polarization switching in planar geometry over wide ranges of film thicknesses and electric field frequencies. 相似文献
12.
In this paper, the photocatalytic degradation of Reactive Black 5 (RB5) was investigated with ferrite bismuth synthesized via ultrasound under direct sunlight irradiation. The intensity of absorption peaks of RB5 gradually decreased by increasing the irradiation time and finally vanished in 50 min in acidic medium. The formation of new intermediate was observed in basic medium. The relative concentration of RB5 in solution and on the surface of ferrite bismuth (BiFeO3) nanoparticles was considered during the experiment in acidic and basic media. The effects of various parameters such as amount of catalyst, concentration of dye, and pH of the solution have been studied on the dye degradation. The adsorption isotherm and the kinetic of photocatalytic degradation of RB5 were investigated. The adsorption constants in the dark and in the presence of sunlight irradiation were compared. The photocatalytic degradation mechanism of RB5 has been evaluated through the addition of some scavengers to the solution. In addition, the stability and reusability of the catalyst were examined in this work. 相似文献
13.
Surzhikov A. P. Pritulov A. M. Peshev V. V. Malyshev A. V. 《Russian Physics Journal》2001,44(11):1244-1247
Electric and magnetic properties of Li–Ti ferrite ceramics depending on sintering modes and controlled by the diffusion-based specimen-to-environment oxygen exchange are considered. The relationship between the properties of ceramics and the character of nonuniform distribution of oxygen in the bulk of a specimen is determined. A physical model of the processes giving rise to nonuniform distribution of oxygen in polycrystalline ferrite ceramics is proposed. The empirical dependences of specific conductivity on sintering time at 1373 K are obtained. 相似文献
14.
A. G. Zhdanov A. K. Zvezdin A. P. Pyatakov T. B. Kosykh D. Viehland 《Physics of the Solid State》2006,48(1):88-95
The specific features of the “incommensurate-commensurate” phase transitions induced by a magnetic field in multiferroics
(materials with coexisting magnetic and electric ordering) are considered. These materials are ferroelectromagnets, for example,
bismuth ferrite BiFeO3 and BiFeO3-based compounds, which have spatially modulated spin structures. It is shown that the interaction between the electric and
magnetic subsystems of the multiferroic material can lead to an electric-field-induced shift of the critical magnetic field
corresponding to the transition from a spatially modulated state to a homogeneous antiferromagnetic state. According to the
theoretical estimates obtained for material parameters characteristic of the bismuth ferrite, this shift is of the order of
0.5 T in an electric field of 50 kV/cm. The phase diagrams are constructed in the “electric field-magnetic field” coordinates.
The results of calculations performed in the harmonic incommensurate structure approximation are compared with the exact soliton
solution. 相似文献
15.
Yu. I. Golovko V. M. Mukhortov O. A. Bunina I. N. Zakharchenko A. S. Anokhin V. B. Shirokov Yu. I. Yuzyuk 《Physics of the Solid State》2010,52(7):1432-1438
Bismuth ferrite films doped with neodymium on MgO single-crystal substrates with an epitaxial barium strontium titanate thin
(1–2 nm) sublayer have been prepared by rf sputtering of ceramic targets at an elevated oxygen partial pressure and at temperatures
below the ferroelectric and magnetic transition temperatures. It has been revealed using X-ray diffraction and Raman scattering
spectroscopy that, in these bismuth ferrite films, a new phase (not observed in bulk samples) is formed. The symmetry of this
phase is monoclinic, the unit cell contains two formula units, and the spontaneous polarization vector deviates from the [111]cub direction and can have different components along the x, y, and z axes. 相似文献
16.
Panithan Sriboriboon Benjaporn Yotburut Oradee Srikimkaew Sartanee Suebka Arreerat Jiamprasertboon Santi Maensiri Worasom Kundhikanjana 《Physics letters. A》2019,383(14):1622-1628
The large piezoelectric coefficient and multiferroicity of bismuth ferrite (BFO) make it an attractive candidate for lead-free ferroelectric devices. However, large leakage currents have limited broader applications. Rare-earth substitutions in BFO have been shown to improve ferroelectric and magnetic properties. In this work, we employed piezoresponse and conductive atomic force microscopy to study ferroelectric domains in Bi1-xSmxFeO3 (x = 0–0.150) grown by the co-precipitation method. The combined piezoresponse and conductivity measurements can directly visualize the local ferroelectric domains under different sample bias. At Sm mol% > 7.5, Sm-substitution effectively lowers defect-generated conductivity. At Sm mol% < 7.5, conductivity increases due to conductive domain walls inside sample grains. The surfaces of these conductive samples exhibit a p-type rectifying behavior while the bulk is n-type. Our work details how the local piezoelectric properties and transport behaviors of BFO ceramics change as a function of Sm-substitution. 相似文献
17.
Ramazanoglu M Ratcliff W Yi HT Sirenko AA Cheong SW Kiryukhin V 《Physical review letters》2011,107(6):067203
Neutron diffraction is used to show that small (~7 MPa, or 70 bar) uniaxial pressure produces significant changes in the populations of magnetic domains in a single crystal of 2% Nd-doped bismuth ferrite. The magnetic easy plane of the domains converted by the pressure is rotated 60° relative to its original position. These results demonstrate extreme sensitivity of the magnetic properties of multiferroic bismuth ferrite to tiny (less than 10(-4)) elastic strain, as well as weakness of the forces pinning the domain walls between the cycloidal magnetic domains in this material. 相似文献
18.
In the present work, zirconium modified bismuth titanate ceramics have been studied as potential lead-free ferroelectric materials over a broad temperature range (RT – 800 °C). Polycrystalline samples of Bi4Ti3−xZrxO12 (x=0.2, 0.4, 0.6) (BZrT) with high electrical resistivity were prepared using the solution combustion technique. The effect of Zr doping on the crystalline structure, ferroelectric properties and electrical conduction characteristics of BZrT ceramics were explored. Addition of zirconium to bismuth titanate enhances its dielectric constant and reduces the loss factor as it introduces orthorhombic distortion in bismuth titanate lattice which is exhibited by the growth along (0010) lattice plane. Activation energy due to relaxation is found to be greater than that due to conduction thus confirming that electrical conduction in these ceramics is not due to relaxation of dipoles. Remanent polarization of the doped samples increases as the Zirconium content increases. 相似文献
19.
A. I. Morosov 《Physics of the Solid State》2014,56(5):865-872
Possible methods and problems of the development of magnetoresistive memory with electric field assisted writing have been considered. It has been shown that the most promising is the memory based on the compensated cut of multiferroic bismuth ferrite BiFeO3. Small values of the weak ferromagnetic moment and linear magnetoelectric effect in BiFeO3 are not obstacles to the realization of the magnetoresistive memory. Of interest is the memory switchable via piezoelectric layer induced elastic stresses, which uses the bistability of magnetization of the ferromagnetic layer. 相似文献
20.
The pressure dependences of the vibration frequencies of the bismuth ferrite crystal lattice in the ferroelectric and paraelectric rhombohedral phases have been calculated from first principles in terms of the LSDA + U approximation. It has been found that there is a linear relationship between the magnetic moments of iron cations and the band gaps calculated using the same parameters of the correlation interaction. An analysis of the pressure dependences of the frequencies of the transverse optical phonons indicates their high stability in both the paraelectric and ferroelectric phases, which is not typical for classical displacive-type ferroelectrics. 相似文献