We report the observation of giant magnetoresistance near room temperature in ferromagnetic films of La1-xSrxMnOz for 0.16≤x≤0.33. For B=5 T, the maximum magnetoresistance ratio [R(0)-R(B)]/R(0) of an annealed film is 60% at 260 K for x=0.2, and 35% at 330 K for x=0.33. Annealed films have higher Curie temperature (Tc), a larger saturation moment and a larger magnetoresistance effect near T c than do as-grown films. The temperature dependence of resistivity for all the samples investigated is unusual, activated above Tc and metallic below Tc. This and the giant magnetoresistance are possibly explained by scattering from magnetic polarons which dominate the transport near Tc.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)