Eur. Phys. J. B 32, 5-11 (2003)
https://doi.org/10.1140/epjb/e2003-00068-8

Insulator-metal transition shift related to magnetic polarons in La_0.67-xY_xCa_0.33MnO₃

Structure Research Laboratory, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, PR China

Corresponding author: ^a lixg@ustc.edu.cn

Received: 27 August 2002
Revised: 2 December 2002
Published online: 14 March 2003

Abstract

The magnetic transport properties have been measured for La_0.67-xY_xCa_0.33MnO₃ () system. It was found that the transition temperature T_p almost linearly moves to higher temperature as H increases. Electron spin resonance confirms that above T_p, there exist ferromagnetic clusters. From the magnetic polaron point of view, the shift of T_p vs. H was understood, and it was estimated that the size of the magnetic polaron is of 9.7~15.4 Å which is consistent with the magnetic correlation length revealed by the small-angle neutron-scattering technique. The transport properties at temperatures higher than T_p conform to the variable-range hopping mechanism.