Lattice effect on charge and magnetic ordering in La _1/3 Sr _2/3 FeO _{3− δ} investigated by mechanical spectroscopy

Abstract

We present an investigation on high-temperature tilting transition and lowtemperature charge and magnetic ordering in La 1/3 Sr 2/3 FeO 3−δ by mechanical spectroscopy. An octahedral tilting transition P m 3m ↔ R 3c appears around 500 K showing up as a huge modulus softening with the decrease in temperature in nearly oxygen stoichiometric La 1/3 Sr 2/3 FeO 3−δ . The modulus softening is mainly due to ferroelastic domain wall motion in rhombohedral structure. A modulus hardening appears at the charge and magnetic ordering. It is expected that the charge and magnetic ordering partially pins the ferroelastic domain walls in La 1/3 Sr 2/3 FeO 3−δ . This proposal was further investigated in a slight oxygen nonstoichiometric La 1/3 Sr 2/3 FeO 3−δ sample and different high-temperature annealed La 1/3 Sr 2/3 FeO 3−δ samples. Our work suggests a special magnetoelastic coupling, the pinning of ferroelastic domain walls by magnetic interaction in La 1/3 Sr 2/3 FeO 3−δ .