Magnetocaloric properties of the La 0.7− xY xSr 0.3MnO 3 giant magnetoresistance ceramics

Abstract

Giant magnetoresistance (GMR), observed in several La 0.7 x A 0.3MnO 3 ceramics, where A is a two-valent addition, is the result of an interaction of conduction electrons and intrinsic magnetization, which is likely to result in unusual magnetocaloric effects. On this basis, magnetization, magnetic entropy change and adiabatic temperature change were measured as a function of Y content in La 0.7− x Y x Sr 0.3MnO 3 ceramics. It is found that doping influences only the transition temperature, while the magnetic entropy change remains constant and displays a saturation tendency in high fields.