Bi(1-x)R(x)FeO(3)(R=rare earth): a family of novel magnetoelectrics

TL;DR

This study explores the structural, ferroelectric, and magnetoelectric properties of Bi(1-x)R(x)FeO(3) crystals with various rare earth elements, revealing the presence of linear and quadratic magnetoelectric effects in specific crystal symmetries.

Contribution

It reports the synthesis and detailed analysis of a new family of magnetoelectric crystals Bi(1-x)R(x)FeO(3) with multiple crystal structures and symmetry-dependent magnetoelectric effects.

Findings

Multiple crystal structures observed across compositions.

Magnetoelectric effects detected only in mm2 symmetry crystals.

Hysteresis observed in magnetoelectric response.

Abstract

Crystals of solid solutions Bi(1-x)R(x)FeO(3),here R= La, Dy, Gd, were obtained with x <=0.7. Solid solutions of the stated rare earths, as x is increased from 0 to 0.7, have one and the same sequence of five crystal structures (rhombohedral C3v 6, triclinic C1 1,orthorhombic D2 6,orthorhombic D2 5, orthorhombic C2v 9). The ferroelectric-paraelectric transition occurs in rhombohedral and triclinic crystals at T=810-560{\deg}C.The high temperature modifications are orthorhombic and cubic. The orthorhombic structure C2v 9 holds up to 1180{\deg}C.The ferroelectric domain structure was distinguished in all types of crystals. No magnetoelectric effect (MEE) was detected in the orthorhombic crystals with the D2 (222) symmetry class. But the mm2 crystals were found to have both quadratic and linear MEE.The value of the quadratic effect is considerably smaller than that ofthe linear one. Magnetoelectric hysteresis takes place in the crystals. The tensorial properties of the obtained crystals are analyzed from the viewpoint of crystal symmetry.