Weak Ferromagnetic Component Research Articles

Anisotropy in the magnetization and magnetoelectric response of single crystalline Mn4Ta2O9

We report temperature dependent magnetization and neutron diffraction measurements on the corundum related magnetoelectric antiferromagnet ${\mathrm{Mn}}_{4}{\mathrm{Ta}}_{2}{\mathrm{O}}_{9}$. Measurements performed on a single crystalline specimen reveal that the magnetization is anisotropic, and a weak ferromagnetic component emerges well within the antiferromagnetically ordered state. Powder neutron diffraction measurements indicate that the magnetic structure comprises of antiferromagnetically coupled ferromagnetic chains of ${\mathrm{Mn}}^{2+}$ spins aligned along the trigonal $c$ axis, in contrast to that reported in other isostructural members of this family. Magnetic measurements performed under a periodic electric field indicate that the magnetoelectric response is also anisotropic, with this coupling along the trigonal $c$ axis and that perpendicular to it having different signs.

Dielectric and magnetic properties of Allium cepa and Raphanus sativus extracts biogenic ZnO nanoparticles

Spherical nanoparticles of zinc oxide (ZnO NPs) have been successfully synthesized through domestic microwave oven-supported solvothermal method by using Allium cepa (Onion) and Raphanus sativus (White Radish) extracts as reducing and capping agent. X-ray powder diffraction confirms the formation of single-nanocrystalline wurtzite-type structure. SEM observations reveal spherical-shaped particles at the nanoscale, while the purity and chemical composition have been confirmed by EDAX analysis. The dielectric study confirms that the dielectric constant and dielectric loss of ZnO nanoparticles decrease with the increase in frequency while increase with the rise in temperature, signifying that the space charge contribution plays a key role in the charge transport process and polarizability. Interestingly, magnetic measurements indicate that the diamagnetic bulk ZnO undergoes magnetic transition into paramagnetic with the presence of a weak ferromagnetic component associated with oxygen vacancies.

Magnetic order and competition with superconductivity in (Ho-Er)Ni2B2C

The rare earth magnetic order in pure and doped Ho(1−x)Er x Ni2B2C (x = 0, 0.25, 0.50, 0.75, 1) single crystal samples was investigated using magnetization and neutron diffraction measurements. Superconducting quaternary borocarbides, RNi2B2C where R = Ho, Er , are magnetic intermetallic superconductors with the transition temperatures ∼10 K in which long range magnetic order develops in the same temperature range and competes with superconductivity. Depending on the rare earth composition the coupling between superconductivity and magnetism creates several phases, ranging from a near reentrant superconductor with a mixture of commensurate and incommensurate antiferromagnetism to an incommensurate antiferromagnetic spin modulation with a weak ferromagnetic component. All of these phases coexist with superconductivity. RKKY magnetic interactions are used to describe the magnetic orders in the pure compounds. However, the doping of Er on Ho sites which have two strong magnetic moments with two different easy directions creates new and complicated magnetic modulations with possible local disorder effects. One fascinating effect is the development of an induced magnetic state resembling the pure and doped R 2CuO4 cuprate with R = Nd and Pr.

Magnetism of Kesterite Cu2ZnSnS4 Semiconductor Nanopowders Prepared by Mechanochemically Assisted Synthesis Method.

High energy ball milling is used to make first the quaternary sulfide Cu2ZnSnS4 raw nanopowders from two different precursor systems. The mechanochemical reactions in this step afford cubic pre-kesterite with defunct semiconducting properties and showing no solid-state 65Cu and 119Sn MAS NMR spectra. In the second step, each of the milled raw materials is annealed at 500 and 550 °C under argon to result in tetragonal kesterite nanopowders with the anticipated UV-Vis-determined energy band gap and qualitatively correct NMR characteristics. The magnetic properties of all materials are measured with SQUID magnetometer and confirm the pre-kesterite samples to show typical paramagnetism with a weak ferromagnetic component whereas all the kesterite samples to exhibit only paramagnetism of relatively decreased magnitude. Upon conditioning in ambient air for 3 months, a pronounced increase of paramagnetism is observed in all materials. Correlations between the magnetic and spectroscopic properties of the nanopowders including impact of oxidation are discussed. The magnetic measurements coupled with NMR spectroscopy appear to be indispensable for comprehensive kesterite evaluation.

Reversal magnetization and exchange bias effect of the nanocrystalline Yb1-xPrxCrO3 solid solution

Polycrystalline samples of Yb1-xPrxCrO3 (0 ≤ x ≤ 1) were synthesized in the whole solubility range by auto-ignition high-temperature synthesis. TEM images revealed a particle size of about 20–25 nm in the solid solution for as-combustion powders. The crystal structure and the chemical state of the cations were characterized by a combination of X-ray diffraction method and X-ray photoelectron spectroscopy. It is found a complete solubility of the Pr ions and a mixed valence state in the Yb-rich composition range (Yb1-xPrxCrO3; 0 < x < 0.5). There, the presence of Yb2+ ions is compensating by the Pr4+ valence states. Besides, the spectroscopy results found a mix of Cr3+ and Cr6+ valence states in the solid solution. Temperature dependence of DC-magnetization measurements showed that the antiferromagnetic transition increases almost linearly from ~ 119 for YbCrO3 to ~ 243 K for PrCrO3. Furthermore, the magnetization reversal observed in the YbCrO3 is progressively weakened with increasing Pr content and disappears for x = 0.30 of Pr substitution. The isothermal magnetization measured below of TN1 and TN2 (2 K) found that the weak ferromagnetism is canceled in the YbCrO3 magnetic ground state. Opposite to this behavior, the end PrCrO3 composition showed a defined magnetic hysteresis loop which infers a weak ferromagnetic component in the magnetic ground state. Besides, the M–H curves showed a negative exchange bias (EB) effect induced by Pr substitution, which is observed above of x = 0.04, and being more intense for x = 0.10 of Pr composition. The vanishing magnetization reversal and exchange bias effect are influenced strongly by the weak ferromagnetic component arising from PrCrO3 sub-lattice in solid solution. The results demonstrate once again, the importance of the interaction between Dzyaloshinsky–Moriya and single-ion anisotropy in the orthochromite family. Also, the results here could stimulate research toward understanding the magnetic ground state whose investigations below TN2 are scares in both compounds.

Synthesis, structure and magnetic properties of a novel double layered brownmillerite Ca2LaFe1.75Cr0.25GaO8

We report the structural and magnetic properties of a novel double layered Brownmillerite Ca2LaFe1.75Cr0.25GaO8. Synchrotron X-ray diffraction and neutron powder diffraction data confirms orthorhombic structure having Pbma space group with tetrahedral chain ordering and ∼ 25 % of cation (Fe/Ga) disorder between octahedral and tetrahedral sites. Ca2LaFe1.75Cr0.25GaO8 exhibits antiferromagnetic transition at TN∼630 K. The magnetic structure is determined as canted G-type antiferromagnetic with weak ferromagnetic component along a direction. The ordered magnetic moments obtained at 4 K are 2.24 (4) μB (Fe3+/Cr3+) for octahedral sites and 2.34 (4) μB (Fe3+) for tetrahedral sites.

Antiferromagnetic and dielectric behavior in polycrystalline GdFe0.5Cr0.5O3 thin film

Single phase materials with both spontaneous electric polarization and magnetization are rare, despite remarkable efforts in developing magnetoelectric multiferroics. In this work, a single-phase polycrystalline GdFe0.5Cr0.5O3 (GFCO) thin film was spin-coated onto a platinized silicon substrate. X-ray diffraction data suggest that the film exhibits an orthorhombic perovskite structure with a Pbnm space group. No other impurity phases were detected. Magnetization measurements reveal the Néel temperature of the GFCO film to be ∼220 K and illustrate a weak ferromagnetic component at 5 K, which could be due to spin canting. Frequency dependent ferroelectric–paraelectric transition was observed around 480 K, indicating the diffuse relaxor-like behavior. The electric field dependent polarization measurements show a lossy behavior below 200 K. The electric field dependent dielectric constant (tunability) measured at 1 MHz in a wide temperature range reveals that the tunability maximizes near the observed dielectric maxima, which further confirms the ferroelectric to paraelectric transition in the present film.

Weak ferromagnetic component in goethite (α-FeOOH) and its relation with microstructural characteristics

Goethite is an antiferromagnetic material that frequently presents a superimposed weak ferromagnetic component. In this research, two goethite samples were prepared using distinct synthesis routes, being later subjected to heat treatment. Magnetization dynamics were analyzed as a function of applied magnetic field and temperature. Moreover, the magnetic measurements were correlated with the resulting microstructures, obtained through scanning and transmission electron microscopy. The results indicate an enhanced ferromagnetic behavior in those goethite samples, with greater presence of defects and imperfections. Besides that, it was observed a reduction of magnetic fluctuations after the healing of the samples via heat treatment. Despite what is vastly proposed in the literature to explain the origin of the magnetic component in goethite, our analysis showed that, for the studied samples, this effect is caused by a magnetic mismatch in the antiferromagnetic lattice. This mismatch is possibly caused by defects as grain boundaries, voids and grain rotations, which may lead to dislocations and consequently to magnetic mismatches in the lattice.

Low‐dimensional Magnetism and Antiferromagnetic Ordering in the Mixed‐valence Spin‐chain Cuprate TlCu2O2

TlCu2O2, a mixed‐valence spin‐chain cuprate, was synthesized in a piston cylinder system starting from thallium sesquioxide Tl2O3, cuprous oxide Cu2O and copper powder. The main structural characteristics are edge‐sharing (CuO2)n zigzag chains, which are linked in the perpendicular crystallographic direction by Cu+ to form a three‐dimensional network. Data from magnetic susceptibility and specific heat measurements show features typical for low‐dimensional magnetic exchange interactions. The long‐range antiferromagnetic ordering is observed at TN = 19.7 K. No weak ferromagnetic component can be detected, suggesting a plain Néel‐type spin‐ordered structure.

Near room temperature spin reorientation and temperature evolution of magnetic structure in Mn substituted HoFeO3

Magnetic structure and spin reorientation transition of 45% Mn substituted HoFeO3 have been investigated using bulk magnetization, neutron powder diffraction and specific heat capacity techniques. These studies confirm the presence of antiferromagnetic ordering of Fe/Mn sublattice below 336 K. The spin reorientation (SR) transition (TSR ~ 290 K) where the magnetic structure changes from Γ4(Ax, Fy, Gz) to Γ1(Gx, Cy, Az) is confirmed by Rietveld analysis of neutron diffraction patterns taken at various temperatures. Though the spin reorientation (SR) transition is happening at 290 K, the system is found to be in mixed Γ4(Ax, Fy, Gz) + Γ1(Gx, Cy, Az) phase from room temperature to 275 K. Below 275 K, the sample exhibits a pure Γ1(Gx, Cy, Az) structure in which the weak ferromagnetic component is absent. Bulk magnetization and specific heat capacity measurements also confirm the Néel temperature and spin reorientation transitions and support the neutron diffraction analysis.

Fabrication and evaluation of highly c-plane oriented Mn3Sn thin films

MnxSn100-x thin films with different compositions (x=84, 80, 76, and 74) were fabricated on MgO (111) substrates by radiofrequency magnetron sputtering at room temperature and their properties were evaluated. The samples crystallized into Mn3Sn after thermal annealing at 400°C or higher in vacuum. The Mn80Sn20 film showed only peaks of the (0001) family in out-of-plane XRD profiles, while the other films additionally showed other diffraction peaks indicating their polycrystalline structure. Cross-sectional transmission electron microscopy confirmed successful fabrication of highly c-plane orientated single-phased Mn3Sn thin film in the x=80 sample. The sample possessed a weak ferromagnetic component in the film plane, whose magnitude was comparable with that of bulk Mn3Sn. On the other hand, the out-of-plane magnetization curve had a linear response within ±5T. This magnetic anisotropy is the same as in bulk Mn3Sn. The Hall curve measured with electric current (magnetic field) along the [011¯0] ([0001]) axis indicated a negligibly small negative anomalous Hall effect (AHE). This response was also the same as in bulk Mn3Sn. We thus concluded that the anisotropies of the magnetic properties and AHE of Mn3Sn in a thin-film form are the same as those of bulk.

Structural disorder and magnetic correlations driven by oxygen doping in Nd2NiO4+δ ( δ∼0.11 )

We investigated the influence of oxygen over-stoichiometry on apical oxygen disorder and magnetic correlations in Nd2NiO4+d (d~0.11) in the temperature range of 2-300 K by means of synchrotron x-ray powder diffraction, neutron single crystal and powder diffraction studies, combined with macroscopic magnetic measurements. In the investigated temperature range, the compound crystalizes in a tetragonal commensurate structure with the P42/ncm space group with excess oxygen atoms occupy the 4b (3/4 1/4 1/4) interstitial sites, coordinated by four apical oxygen atoms. Large and anisotropic thermal displacement parameters are found for equatorial and apical oxygen atoms, which are strongly reduced on an absolute scale compared to the Nd2NiO4.23 phase. Maximum Entropy analysis of the neutron single crystal diffraction data uncovered anharmonic contributions to the displacement parameters of the apical oxygen atoms, toward the nearest vacant 4b interstitial site, related to the phonon assisted oxygen diffusion mechanism. Macroscopic magnetization measurements and neutron powder diffraction studies reveal long-range antiferromagnetic ordering of the Ni-sublattice at TN ~ 53 K with a weak ferromagnetic component along the c-axis, while the long-range magnetic ordering of the Nd-sublattice occurs below 10 K. Temperature dependent neutron diffraction patterns show the appearance of a commensurate magnetic order at TN with the propagation vector k = (100) and the emergence of an additional incommensurate phase below 30 K, while both phases coexist at 2 K. The commensurate magnetic structure is best described by the P42/nc`m` Shubnikov space group. Refined magnetic moments of the Ni and Nd-sites at 2 K are 1.144(76) muB and 1.632(52) muB respectively. A possible origin of the incommensurate phase is discussed and a tentative magnetic phase diagram is proposed.

Structure of nanocrystalline Nd0.5R0.5FeO3 (R=La, Pr, and Sm) intercorrelated with optical, magnetic and thermal properties

Polycrystalline samples of Nd0.5R0.5FeO3 (R = La, Pr and Sm) synthesized by sol-gel combustion method have been investigated for their structural, optical, thermal and magnetic properties. X-ray diffraction in combination with Fourier transform infrared (FTIR) spectra confirm the single-phase orthorhombic structure with Pbnm space group of all the samples. Rietveld refinement employed to determine the bond lengths (Fe–O, R–O) and bond angles (Fe–O–Fe) show a decrease in the bond angle with Sm doping. Transmission electron microscopy (TEM) micrographs reveal the nano-size particles and selected area electron diffraction (SAED) patterns indicate good crystallinity with a uniform distribution of particles throughout the samples. Raman spectra clearly indicate the compressive strain in the Sm doped sample that has been correlated with the structural parameters obtained from Rietveld refinement. The shift in wavenumber is the main cause of change in bond length (Fe–O) and tilt of octahedra due to rare earth ions. The optical bandgap is determined using Tauc's relation from the diffuse reflectance spectra. The variation of specific heat has been investigated with temperature in a broad temperature range. The endothermic peak in specific heat has been correlated with magnetic order. The value of Néel temperature increases in the case of La-doped sample and reduces for the Pr doping. However, the decrease of specific heat in Sm doped sample around 300 °C may be attributed due to the spin reorientation. Magnetic studies at room temperature reveal antiferromagnetic behavior with weak ferromagnetic component due to the canted ordering of Fe3+ spins. Magnetic properties are strongly dependent on the type of rare earth ion as the maximum magnetization (Mm) is enhanced from 0.259 to 0.434 emu/g with the doping of rare earth ions (La, Pr and Sm). The increase in magnetization has been correlated with increased distortion which is evident from the decrease in the bond angle. Exchange bias (EB) effect is observed for all samples as single-phase orthorhombic structure is composed of antiferromagnetic (AFM) and ferromagnetic (FM) phases.

Synthesis, structural, magnetic and thermal properties of Mn2As2O5, the first pyro-arsenite of a first-row transition metal

Single crystals of manganese pyro-arsenite [systematic name: dimanganese(II) pentaoxidodiarsenate(III)], Mn2As2O5, were grown under hydrothermal conditions. Mn2As2O5 adopts a novel structure type as revealed by single crystal X-ray diffraction from a crystal twinned by pseudo-merohedry. The crystal structure comprises of five independent MnII sites (two located on inversion centres, three in general sites) and two pairs of [As2O5]4-pyro-anions made up from corner-sharing trigonal-pyramidal [AsO3] units in general positions. Four of the five MnII sites exhibit distorted octahedral [MnO6] coordination polyhedra whereas one has five oxygen ligands in a distorted square-pyramidal environment. The manganese-oxygen polyhedra and [As2O5]4-pyro-anions share corners and edges under formation of a three-dimensional network with channels extending along [001]. The 4s2 electron lone pairs at the AsIII atoms are stereochemically active and point into the centre of the channels. Results of Raman spectroscopic studies are in agreement with the structural features of the pyro-arsenite anion. Magnetic susceptibility measurements on a powder sample confirm all Mn atoms to be in oxidation state ​+ ​II. An antiferromagnetic ordering below 14.3 ​K occurs that most likely points to a magnetic structure supporting a weak ferromagnetic component (‘weak ferromagnetism’).

Magnetic inversion symmetry breaking and spin reorientation in Tb2MnNiO6 : A polar strong ferromagnet

We report a description and comprehensive study on four successive magnetic transitions in ferromagnetic $\mathrm{T}{\mathrm{b}}_{2}\mathrm{MnNi}{\mathrm{O}}_{6}$ double perovskite. In the ground state ($P{2}_{1}^{\ensuremath{'}}$), the moments of magnetic $A$ and $B$ sites order according to different nonpolar magnetic modes, but the coupling between them generates an overall polar symmetry which makes this oxide potentially multiferroic due to magnetic trilinear coupling, and therefore ferromagnetic and ferroelectric in its ground state. Its macroscopic magnetization is large ($5\phantom{\rule{0.16em}{0ex}}{\ensuremath{\mu}}_{\mathrm{B}}/\mathrm{f}.\mathrm{u}$) and not related to a weak ferromagnetic component induced by Dzyaloshinskii-Moriya interaction. However, a sharp and severe spin reorientation of the ferromagnetic transition-metal moments has been observed which opens the door to the magnetic switching of the ferroelectric state in this perovskite, and conversely to the control of the magnetization direction by electrical fields applied parallel to $b$. We also anticipate that in this material the direction of the magnetization (towards $c/a$) could be used as the key to switch the polar/nonpolar (ferroelectric/antiferroelectric) transformation.

Use of ultrasound-assisted co-precipitation route to obtain CuMnO2 semiconductor nanomaterials

CuMnO2 nanoparticles were obtained for the first time by sonochemical synthesis in an aqueous solution of sodium hydroxide containing soluble copper and manganese nitrate reactants without any further thermal treatment. Experiments were performed at different lengths of time (20 min, 30 and 40 min) and ultrasound amplitude of 80%. The materials present the expected crednerite structure (C2/m space group), and the nanoparticles average size and morphology for each sample are studied by nanoparticle tracking analysis method, respectively, by transmission electron microscopy. The as-obtained materials display p-type semiconductivity behavior at room temperature and the value for direct optical band gap EG is estimated to be approximately ~ 3.6 eV. The study of the magnetic properties for the nanocrystalline crednerite samples reveals 2D magnetic behavior below 110 K and a weak ferromagnetic component at ~ 20 K.

Comparative study of magnetic and electronic properties of room‐temperature polar magnets ScFeO3 and InFeO3

We performed calculations based on collinear and non‐collinear spin density functional theory to investigate magnetic and electronic properties of new room‐temperature polar magnetic compounds AFeO3 (A = Sc, In). Exchange and correlation effects were simulated by standard local spin density approximation and the generalized gradient approximation. We determined that the canted G‐type antiferromagnetic (G‐AFM) structure of the Fe spin moments is the most stable magnetic structure for both compounds, in accordance with experimental facts. The calculated Fe spin magnetic moments and resulting weak ferromagnetic components perpendicular to the c‐axis also agree well with the experiment. The magnitude of the Fe spin moment does not depend on the fact if the G‐AFM structure is collinear or canted. The energy difference between these two structures is found to be much larger for InFeO3, so as the exchange interaction constant Jnn between nearest‐neighbor magnetic Fe ions. The ScFeO3 and InFeO3 electronic structures, which reproduce well their magnetic properties are presented and discussed. By comparing them with the band structures of some typical multiferroics, we conclude that different electronic mechanisms should be responsible for their ferroelectric distortion. In ScFeO3, the cause of this distortion should be attributed to the hybridization between almost empty Sc 3d and occupied O 2p states along the hexagonal c‐axis. For InFeO3, however, the stereochemical activity of the In 5s localized electrons should be the principal driving force for ferroelectric distortion.

Structural, magnetic and magnetodielectric study in the layered oxide BiPbSr2MnO6

Layered oxide BiPbSr2MnO6 (BPSMO) is investigated from structural, magnetic and magnetodielectric perspective. Room temperature Rietveld refinement of neutron powder diffraction pattern shows that the compound crystallizes in orthorhombic ‘Amaa’ structure. Along with an antiferromagnetic ordering (TN) at 190 K, a weak ferromagnetic component is substantiated from magnetization isotherm measured at 175 K as well as temperature dependent neutron powder diffraction. Magnetic reflections were indexed in the nuclear lattice with propagation vector k = (0, 0, 0). Rietveld refinement of powder pattern at 2.8 K demonstrates that magnetic moments are almost normal to the a–b plane in an antiferromagnetic arrangement, but are canted slightly towards a–b plane. The Jahn–Teller distortion shows a substantial increase in the ordered state with decrease in temperature while the variation is trifling above the ordering temperature. The dielectric measurement shows a contrasting nature of the dielectric data for temperatures below and above TN, thus hinting a plausible magnetodielectric (MD) coupling. A confirmation to this coupling is seen in the temperature and field dependent magnetodielectric (MD) results. Substantial MD effect of ~ − 2% is observed at 175 K, near to the vicinity of magnetic transition.

Multiferroic properties of RFe0.5Co0.5O3 with R=Tm , Er, Ho, Dy, and Tb

We present a detailed study of the thermal dependence of the neutron powder diffraction (NPD) of $R\mathrm{F}{\mathrm{e}}_{0.5}\mathrm{C}{\mathrm{o}}_{0.5}{\mathrm{O}}_{3}$ perovskites ($R=\mathrm{Tm}$, Er, Ho, Dy, and Tb) combined with a complete characterization of their magnetic, electric transport and ferroelectric properties. All samples are described with an orthorhombic (Pbnm) crystallographic structure. The inverse of magnetic susceptibility at high temperature shows an effective magnetic moment with contributions of high-spin $\mathrm{C}{\mathrm{o}}^{3+}$, $\mathrm{F}{\mathrm{e}}^{3+}$, and the corresponding rare-earth cations (${R}^{3+}$) moments. Negative Curie-Weiss temperatures indicate antiferromagnetic (AFM) correlations between the magnetic ions. At low temperature, the reduced magnetic saturation values are associated with crystal-field effects on ${R}^{3+}$ ions. Below 300 K, magnetic reflections in NPD data show that the spin configuration in the ordered state is AFM type-G with a weak ferromagnetic component along the $c$ axis (${\mathrm{\ensuremath{\Gamma}}}_{4}$) for transition metal ions. Spin reorientation (SR) transitions are observed, changing the irreducible representation from ${\mathrm{\ensuremath{\Gamma}}}_{4}$ (${G}_{x}$) to ${\mathrm{\ensuremath{\Gamma}}}_{2}({G}_{z})$ at low temperatures, except for the Ho compound where it changes from ${\mathrm{\ensuremath{\Gamma}}}_{4}$ (${G}_{x}$) to ${\mathrm{\ensuremath{\Gamma}}}_{1}({G}_{y})$. Magnetization data under field cooling (FC) and zero field cooling (ZFC) protocols show reversal magnetization for $R=\mathrm{Er}$ and Tb. A significant change of the slope of the M vs T curves is associated with the onset of magnetic order (${T}_{N1}\ensuremath{\sim}250\phantom{\rule{0.16em}{0ex}}\mathrm{K}$) of Fe/Co sublattice. The electric conductivity at room temperature shows that Tm value is ten times less than the other rare earths. The temperature dependence of the electrical conductivity can be described with a variable range hopping model ($\mathrm{ln}\ensuremath{\sigma}\ensuremath{\sim}{T}^{\ensuremath{-}1/4}$). Also, in the Tm case, the complex electrical permittivity shows a different behavior in comparison with the other members of the series. Finally, the Tm sample can be polarized when the specimen is cooled under different values of electrical field (E). Pyroelectric current can be detected while the sample is warming and depolarized, showing the ferroelectric critical temperature (${T}_{C}$) at ${T}_{N1}$. A low electric polarization of $400\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}\mathrm{C}/{\mathrm{m}}^{2}$ was measured for $\mathrm{TmF}{\mathrm{e}}_{0.5}\mathrm{C}{\mathrm{o}}_{0.5}{\mathrm{O}}_{3}$.

Unusual magnetic properties of the polar orthorhombic BiFe0.5Sc0.5O3 perovskite

Magnetic properties of new multiferroic BiFe0.5Sc0.5O3 perovskite which exists in two different orthorhombic polymorphs, the antipolar Pnma and the polar Ima2, were studied using a SQUID-magnetometer technique in magnetic fields up to 50 kOe in the temperature range of 5–300 K. Both polymorphs show a weak ferromagnetic component below the Néel temperature, TN∼220 K. A wide cusp-like anomaly of the temperature dependent magnetic susceptibility was revealed below 200 K. The anomaly is dependent on the magnetic field applied and can be associated with the glassy magnetic behavior of the compound. The best fit of the initial magnetization curves taken at each temperature can be obtained as a sum of two contributions, namely the nonlinear in field and the linear one. The nonlinear contribution appeared to be temperature and magnetic field dependent, which is in a good agreement with the magnetization experimentally obtained as a function of temperature in different magnetic fields applied. Increase of external magnetic field leads to a decrease of the nonlinear contribution to the total magnetic moment.