First principles study of structural, electronic and magnetic interplay in ferroelectromagnetic yttrium manganite

Abstract

We present results of local spin density approximation (LSDA) pseudopotential calculations for the ferroelectromagnet, yttrium manganite (YMnO3). The origin of the differences between ferroelectric and non-ferroelectric perovskite manganites is determined by comparing the calculated properties of yttrium manganite in its ferroelectric hexagonal and non-ferroelectric orthorhombic phases. In addition, orthorhombic YMnO3 is compared with the prototypical non-ferroelectric manganite, lanthanum manganite. We show that, while the octahedral crystal field splitting of the cubic perovskite structure causes a centro-symmetric Jahn-Teller distortion around the Mn 3+ ion, the markedly different splitting in hexagonal perovskites creates an electronic configuration consistent with ferroelectric distortion. We explain the nature of the distortion, and show that a local magnetic moment on the Mn 3+ ion is a requirement for it to occur. pacs numbers 75.50. Dd,71.15.Mb

Co-precipitation/hydrothermal synthesis of BiFeO3 powder

“…This is one of evidences of the antiferromagnetic and ferroelectricity of the obtained BiFeO 3 powders. The Curie temperature of 828 ℃ was in agreement with references [1] , while the Néel temperature of 301 ℃ was about 70 ℃ lower than reported elsewhere [1] , which are under further investigation.…”

“…It exhibits rhombohedrally distorted perovskite structure and has antiferromagnetic ordering with Néel temperature (T N ) of about 370 ℃ and ferroelectric properties with a high Curie temperature (T C ) of about 830 ℃ [1] . However, conditions for synthesizing single phase BiFeO 3 were critical by conventional solid-state reaction in bulk materials since the temperature stability range of the phase was very narrow.…”

Multiferroic PbFe12O19 ceramics

“…PbFe 12 O 19 is the one we are looking for. As the electric polarization was found in materials of YMnO 3 [14], ErMnO 3 [15] , LiNbO 3 and BiFeO 3 with hexagonal structure, it opens up a new direction for potential multiferroic candidate of such magnetic materials as PbFe 12 O 19 having hexagonal structure.…”

Structural transformation and charge transfer induced ferroelectricity and magnetism in annealed YMnO3

“…1 RMnO 3 favors a three-dimensional (3D) magnetic structure with Mn-O-Mn superexchange bonding, leading to an antiferromagnetic (AFM) state with Neel temperature T N ∼40 K and a ferroelectric (FE) state with Curie temperature T c ∼30 K. [8][9][10] In contrast, for R = Ho-Lu, Sc, Y, and In, which have smaller ionic radii, RMnO 3 favors a hexagonal phase with a P6 3 cm SG, consisting of two non-connected layers of MnO 5 bipyramids that are separated by a layer of R 3+ ions, as shown in resulting in an AFM state with T N ∼100 K. [11][12][13] The hexagonal manganites exhibit a distinct FE transition with a high FE T c of around 900 K, which has been suggested to be a result of the 1D Mn d 0 -ness behavior, based on first-principles calculations. [14][15][16][17] In the 1D Mn d 0 -ness model, the crystal field of the MnO 5 bipyramids splits the 3d orbitals of the Mn 3+ ions into two doublets (e 1g and e 2g ) and a singlet (a 1g ). The four d electrons of the Mn 3+ ions occupy the lower energy orbitals e 1g and e 2g , and the mostly unoccupied a 1g orbitals can hybridize with oxygen (O T ) to induce FE distortion along the c-axis.…”