Multiferroicity of 2H-BaMnO3 Single Crystal

Abstract

Geometric ferroelectrics are called as improper ferroelectrics where geometric structural constraints, rather than typical cation-anion pairing, induce proper ferroelectric polarization. Trimerization of MnO5 bipyramids, a kind of geometric structural distortions, is observed in RMnO3 (R = Ho, Er, Yb, Lu, Y), which share same symmetric group with 2H-BaMnO3. And the distortion induces intriguing multiferroicity such as topological vortex-antivortex, angle dependent conducting domain walls, enhanced magnetoelectric coupling at domain walls, etc. In hexagonal RMnO3, it has been unavailable to study thermodynamic behavior of trimerization and polarization because of high ferroelectric transition temperature (1120-1435°C). But it was reported that polycrystalline 2H-BaMnO3 exhibits antiferromagnetic order at 59 K [1], and ferroelectric transition at 130 K [2]. Here, we present ferroelectric and magnetic properties of single crystalline 2H-BaMnO3.

[1] E. J. Cussen and P. D. Battle, Chem. Mater. 12, 831-838 (2000) [2] Stanislav Kamba et al, Physical Review B 95, 174103 (2017)