Unusual large magnetostriction in the ferrimagnet Gd 2/3 Ca 1/3 MnO 3

Abstract

We report an unusual large linear magnetostrictive effect in the ferrimagnet Gd2/3Ca1/3MnO3 (Tc ≈ 80 K). Remarkably, the magnetostriction, negative at high temperature (T ≈ Tc), becomes positive below 15 K when the magnetization of the Gd sublattice overcomes the magnetization of the Mn sublattice. A rather simple model where the magnetic energy competes against the elastic energy gives a good account of the observed results and confirms that Gd plays a crucial role in this unusual observation. Unlike previous works in manganites where only striction associated with 3d Mn orbitals is considered, our results show that the lanthanide 4f-orbitals–related striction can be very important too and it cannot be disregarded.