Effects of sintering temperature on physical properties of nanocrystalline La_0.85Na_0.15MnO₃ ceramics

¹ Department of Physics, Zhoukou Normal University, Zhoukou 466000, P.R. China
² Department of Technology and Physics, Zhengzhou University of Light Industry, Zhengzhou 450002, P.R. China

^a e mail: liukuili@zknu.edu.cn

Received: 1 August 2010
Revised: 1 April 2011
Accepted: 29 July 2011
Published online: 14 November 2011

Abstract

Nanocrystalline La_0.85Na_0.15MnO₃ ceramics were prepared via a novel method based on chemical solution combustion. Effects of sintering temperature on electrical transport and magnetic properties were systematically investigated. It was found that the resistivity increases, the magnetization decreases, and the metal-insulator transition temperature shifts toward low temperatures with the decrease of the sintering temperature. In addition, the magnetization of the samples sintered at low temperatures exhibits a broadened paramagnetic-to-ferromagnetic transition temperature. The low field magnetoresistance evidently increases with decreasing the sintering temperature due to the spin-polarized intergranular tunneling.