ESR STUDIES ON GMR RELATED MATERIALS II: ESR of Mn IN La_0.97Ca_0.03MnO₃

Abstract

ESR measurements have been carried out for La 0.97 Ca 0.03 MnO 3 at temperatures from 4 K up to 760 K. below ≃243 K , two kinds of spectra, the high-field and low-field signals, are observed down to 96 and 4 K, respectively. They are assumed to be due to Mn 4+ and Mn 3+ ions, respectively. From the g-shifts of the high-field ( Mn 4+) signals, the magnetic interaction coefficient between Mn 4+ and Mn 3+ spins is estimated. Clear single ESR was observed above ≃255 K , and its linewidth and intensity are obtained as a function of temperature. The linewidth nearly follows exp (-550/T), and the intensity gradually deviates from Curie's law below ≃550 K , presumably due to the spin-cluster formation.