Mössbauer effect in ferroelectric-antiferromagnetic BiFeO3

Bhide, V. G.; Multani, M.S.

doi:10.1016/0038-1098(65)90031-1

Cited by 83 publications

(46 citation statements)

References 4 publications

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“…Though the physics of ferroelectricity and magnetoelectric (ME) coupling in AMnO 3 is very exciting, they are not useful for practical applications at room temperature since the magnetic field-induced ferroelectric polarization is rather small and the magnetic transition occurs mostly below the liquid nitrogen temperature. The ferrimagnetic magnetic transition of PbFe 0.5 Nb 0.5 O 3 is also below 300 K. 8 The high values of ferroelectric Curie temperature (T C(FE) ~ 836 °C) 9,10 and antiferromagnetic transition temperature (T N ~ 370 °C) 11 found in BiFeO 3 make this compound more attractive. Ferroelectricity in BiFeO 3 is driven by the sterochemical 2 activity of 6s 2 lone pair of Bi 3+ ions, whereas the Fe ions order antiferromagnetically.…”

Section: Introductionmentioning

confidence: 99%

Magnetic and magnetoelectric studies in pure and cation doped

Naik

Mahendiran

2009

Solid State Communications

124

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We report the effect of divalent cation (A) substitution on magnetic and magnetoelectric properties in Bi 1-x A x FeO 3 (A= Sr, Ba and Sr 0.5 Ba 0.5 ; x = 0 and 0.3). The rapid increase of magnetization below 100 K and a peak at the Neel temperature T N = 642±2 K found in BiFeO 3 is suppressed in the co-doped sample (A = Sr 0.15 Ba 0.15 ). All the divalent cation doped samples show enhanced magnetization with a well defined hysteresis loop compared to the parent compound. Both longitudinal (L-α ME ) and transverse (T-α ME ) magnetoelectric coefficients with dc magnetic field parallel and perpendicular to the direction of induced voltage, respectively, were measured using dynamic lock-in technique. It is found that the T-α ME increases in magnitude and exceeds the L-α ME with increasing size of the A cation. The maximum T-α ME = 2.1 mV/cmOe in the series is found for A = Sr 0.15 Ba 0.15 , though it is not the compound with the highest saturation magnetization. The observed changes in the magnetoelectric coefficient are suggested to possible modification in the domain structure and magnetoelectric coupling in these compounds.1

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Section: Introductionmentioning

confidence: 99%

Magnetic and magnetoelectric studies in pure and cation doped

Naik

Mahendiran

2009

Solid State Communications

124

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“…1100 K) and exhibits antiferromagnetic behavior with high Néel temperature (T N ; ca. 643 K) [6,7,8]. The Fe magnetic moments are coupled ferromagnetically (F) within the pseudocubic (111) planes and antiferromagnetically (AF) between adjacent planes.…”

Section: Introductionmentioning

confidence: 99%

Theoretical investigation of magnetoelectric behavior inBiFeO3

et al. 2006

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The magnetoelectric behavior of BiFeO3 has been explored on the basis of accurate density functional calculations. We are able to predict structural, electronic, magnetic, and ferroelectric properties of BiFeO3 correctly without including any strong correlation effect in the calculation. Unlike earlier calculations, the equilibrium structural parameters are found to be in very good agreement with the experimental findings. In particular, the present calculation correctly reproduced experimentally-observed elongation of cubic perovskite-like lattice along the [111] direction. At high pressure we predicted a pressure-induced structural transition from rhombohedral (R3c) to an orthorhombic (P nma) structure. The total energy calculations at expanded lattice show two lower energy ferroelectric phases (with monoclinic Cm and tetragonal P 4mm structures), closer in energy to the ground state phase. Spin-polarized band-structure calculations show that BiFeO3 will be an insulator in A-and G-type antiferromagnetic phases and a metal in C-type antiferromagnetic, ferromagnetic configurations, and in the nonmagnetic state. Chemical bonding in BiFeO3 has been analyzed using partial density-of-states, charge density, charge transfer, electron localization function, Born-effective-charge tensor, and crystal orbital Hamiltonian population analyses. Our electron localization function analysis shows that stereochemically active lone-pair electrons are present at the Bi sites which are responsible for displacements of the Bi atoms from the centro-symmetric to the noncentrosymmetric structure and hence the ferroelectricity. A large ferroelectric polarization of 88.7 µC/cm 2 is predicted in accordance with recent experimental findings, but differing by an order of magnitude from earlier experimental values. The strong spontaneous polarization is related to the large values of the Born-effective-charges at the Bi sites along with their large displacement along the [111] direction of the cubic perovskite-type reference structure. Our polarization analysis shows that partial contributions to polarization from the Fe and O atoms almost cancel each other and the net polarization present in BiFeO3 mainly (> 98%) originates from Bi atoms. We found that the large scatter in experimentally reported polarization values in BiFeO3 is associated with the large anisotropy in the spontaneous polarization.

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“…7,3 Palai et al 8 using several structural and optical techniques proposed the rhombohedral R3c -α-phase for temperatures below T C , an intermediate paraelectric -β-phase between 1130 to 1225 K, and a cubic -γ-phase above at T ~1225-1233 K, coincident with an hypothetically high temperature insulator-metal phase transition. BiFeO 3 in the rhombohedrally distorted phase has ferroelectric, antiferromagnetic, and ferroelastic ordering above 300 K. 9 It orders antiferromagnetically below T N ~640 K in a spiral spin incommensurate structure 10,11,12,13 24 Low temperature infrared and Raman active phonons were also calculated from first principles by Hermet et al 25 and by Tütüncü and Srivastava. 26 Here we discuss our measurements for BiFeO 3 combining far infrared reflectivity and emission spectroscopy putting emphasis on the high temperature ferroelectric to paraelectric poorly understood phase transition at T C~1 090 K.…”

Section: I-introduction -mentioning

confidence: 99%

High temperature emissivity, reflectivity, and x-ray absorption of BiFeO3

Massa

Campo

Meneses

et al. 2010

Journal of Applied Physics

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We report on the lattice evolution of BiFeO 3 as function of temperature using far infrared emissivity, reflectivity, and X-ray absorption local structure.A power law fit to the lowest frequency soft phonon in the magnetic ordered phase yields an exponent β=0.25 as for a tricritical point. At about 200 K below T N ~640 K it ceases softening as consequence of BiFeO 3 metastability. We identified this temperature as corresponding to a crossover transition to an order-disorder regime. Above ~700 K strong band overlapping, merging, and smearing of modes are consequence of thermal fluctuations and chemical disorder. Vibrational modes show band splits in the ferroelectric phase as emerging from triple degenerated species as from a paraelectric cubic phase above T C ~1090 K. Temperature dependent X-ray absorption near edge structure (XANES) at the Fe K-edge shows that lower temperature Fe 3+ turns into Fe 2+ . While this matches the FeO wüstite XANES profile, the Bi L III -edge downshift suggests a high temperature very complex bond configuration at the distorted A perovskite site. Overall, our local structural measurements reveal high temperature defect-induced irreversible lattice changes, below, and above the ferroelectric transition, in an environment lacking of long-range coherence. We did not find an insulator to metal transition prior to melting.

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Mössbauer effect in ferroelectric-antiferromagnetic BiFeO3

Cited by 83 publications

References 4 publications

Magnetic and magnetoelectric studies in pure and cation doped

Magnetic and magnetoelectric studies in pure and cation doped

Theoretical investigation of magnetoelectric behavior inBiFeO3

High temperature emissivity, reflectivity, and x-ray absorption of BiFeO3

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