Charge ordering transition in (La, Pr)_1/3Sr_2/3FeO_3−δ with different oxygen concentration investigated by mechanical spectroscopy

¹ National Laboratory of Solid State Microstructures and School of Physics, Nanjing University Nanjing 210093, China
² Collaborative Innovation Center of Advanced Microstructures - Nanjing 210093, China

^(a) xnying@nju.edu.cn

Received: 15 March 2015
Accepted: 27 April 2015

Abstract

We present the results of the kilohertz mechanical spectrum of oxygen-varied La_1/3Sr_2/3FeO_3−δ and Pr_1/3Sr_2/3FeO_3−δ. On cooling, a substantial modulus softening above the charge ordering transition temperature T_CO, and an abrupt stiffness and step-like decrease of the internal friction below T_CO were observed in oxygen stoichiometric La_1/3Sr_2/3FeO_3−δ. No step-like change of the mechanical spectrum was observed in charge-ordered Pr_1/3Sr_2/3FeO_3−δ, which shows the absence of dynamic Jahn-Teller distortions in Pr_1/3Sr_2/3FeO_3−δ. Another modulus softening below was observed in charge-ordered (La, Pr)_1/3Sr_2/3FeO_3−δ, which was used to discriminate the charge ordering transition from the charge disproportionation transition in perovskite iron oxides.