Crystalline and magnetic transitions in La-Ca-Sr manganites: ESR study

M. T. CAUSA; M. OTERO-LEAL; E. WINKLER; M. GRANADA; G. ALEJANDRO; C. A. RAMOS; M. TOVAR; D. LAURA-CCAHUANA; J. RIVAS

Río de Janeiro, Brasil

Workshop; VIII Latin American Workshop on Magnetism, Magertic Materials and their Applications; 2007

Phases coexistence is usually observed in manganites of the family La-Ca and is absent in the La-Sr series. Other physical properties (Specific Heat, Magnetization and Dilatometry) show different characteristics comparing La0.67A0.33MnO3 with A = Ca and A = Sr.  The differences were explained considering that the compound with A = Ca shows a first order magnetic transition while La-Sr is a second order compound.  Studies on the series La0.67(Ca1-xSrx)0.33MnO3 have related the 1st and 2nd order character to the crystalline structure which is orthorhombic (O) for A = Ca and rhombohedral (R) for A = Sr.