Mechanism of exchange striction of ferroelectricity in multiferroic orthorhombic HoMnO3 single crystals


Lee N., CHOI Y. J. , Ramazanoglu M. K. , RATCLIFF W., KIRYUKHIN V., CHEONG S. -.

PHYSICAL REVIEW B, vol.84, no.2, 2011 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 84 Issue: 2
  • Publication Date: 2011
  • Doi Number: 10.1103/physrevb.84.020101
  • Title of Journal : PHYSICAL REVIEW B

Abstract

E-type perovskite magnet HoMnO3 is considered to be a prototype Mn-Mn exchange-striction driven multiferroic. We have grown orthorhombic HoMnO3 single crystals and studied the directional dependence of their electric polarization P. The direction of P is not along the crystallographic a axis, as predicted, but along the c axis. The magnetic state is incommensurate. The direction P along the c axis is primarily induced by Ho-Mn exchange striction, and Mn-Mn striction in the incommensurate spin state leads to an antiferroelectric order along the a axis. We predict the rotation of P with temperature in commensurate E-type RMnO3 (R denotes magnetic rare earth).