Magnetically-Driven Ferroelectric Atomic Displacements in perovskite like YMnO3

TL;DR

This study observes magnetically-induced ferroelectric atomic displacements in YMnO3 using synchrotron x-ray diffraction, revealing bond alternation and spontaneous polarization, supported by first-principles calculations.

Contribution

It provides experimental evidence of magnetically-driven ferroelectric displacements in YMnO3 and confirms polarization through theoretical calculations.

Findings

Ferroelectric displacements of ~10^{-3} Å observed

Bond alternation driven by exchange striction identified

Theoretical calculations reproduce observed polarization

Abstract

Magnetically-driven ferroelectric atomic displacements of the order of 10$^{-3} Angstrom have been observed in orthorhombic (perovskite like) YMnO$_3$ by a single-crystal synchrotron x-ray diffraction. The refined polar structure shows the characteristic bond alternation driven by the exchange striction in staggered Mn-O-Mn arrays with $\uparrow\uparrow\downarrow\downarrow$ type ordering, giving rise to a spontaneous polarization along a-axis. First-principles calculations based on the Berry phase method as well as on the experimentally refined crystal structure can reproduce the observed polarization value.