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SPIN DYNAMICS INVESTIGATED BY MAGNETIC RESONANCE IN COLOSSAL MAGNETORESISTIVE MATERIALS

L. V. Giurgiu1,*

Affiliation

  1. National Institute for Research & Development of Isotopic and Molecular Technologies P. O. Box 700, 3400 Cluj-Napoca, Romania

Abstract

The spin dynamics in colossal magnetoresistive manganites La2/3Ca1/3Mn1-xDixO3 (Di = Al, In; x 0.05) has been analysed by ESR spectroscopy. The effect of the partial substitution of Mn by closed shell ions was evidenced. The temperature and x dependence of the resonance linewidth and integral intensity of the ESR signal have been investigated and disscused in terms of the bottlenecked spin relaxation and small polaron hoping models. The exchange coupling integral between Mn3+ and Mn4+ ions shows a decrease with increasing x due to the weakening of the double exchange interaction upon doping. A strong variation of the polaron activation energy with the doping level was also found and discussed in terms of the Mn - O distortion and the Mn3+ content..

Keywords

Colossal magnetoresistive perovskites, ESR, Spin dynamics.

Submitted at: July 29, 2002
Accepted at: March 12, 2003

Citation

L. V. Giurgiu, SPIN DYNAMICS INVESTIGATED BY MAGNETIC RESONANCE IN COLOSSAL MAGNETORESISTIVE MATERIALS, Journal of Optoelectronics and Advanced Materials Vol. 5, Iss. 1, pp. 279-287 (2003)