ESR STUDIES ON GMR RELATED MATERIALS IV: ESR OF Mn IN La_0.7Ca_0.3MnO₃

Abstract

ESR measurements have been carried out on La 0.7 Ca 0.3 MnO 3. Distorted signals have been observed below about 255 K, but clear signals above ≃ 270 K . The temperature dependence of the low-temperature ESR linewidth nearly follows the magnetization (or susceptibility). The ESR intensity exhibits an anomalous increase at temperatures between about 200 K and 260 K with a peak at around 250 K; quite similar behavior to that of the resistivity, indicating a possible correlation between the resistivity and the ESR intensity. The temperature dependence of the ESR linewidth and intensity has been also studied above 300 K.

Chemical disorder reinforces magnetic order in ludwigite (Ni,Mn)3BO5 with Mn4+ inclusion

“…Using this parameters, the effective magnetic moment of the formula unit was estimated via relation , and it is . Effective magnetic moment also was calculated theoretically via ∑( ( ) ) ⁄ (only spin component of the effective magnetic moment was taken into account), where N is composition x, g is g-factor of ions Mn 3+ (g=2 [29]), Mn 4+ (g=1.96 [30]) and Ni 2+ (g=2.08 [31]) in octahedral coordination, obtained in other works. Calculated value of effective magnetic moment agrees with the value of experimentally estimated effective magnetic moment within the error determination of Curie constant C and corresponds to the high-spin states S(Ni…”