Positive magnetoresistance in low-doped La1−xSrxMnO3 (x⩽0.14) perovskites

Abstract
The magnetic and transport properties, under magnetic field and hydrostatic pressure, in a series of single crystalline samples of low-doped La1−xSrxMnO3 (0.1⩽x⩽0.14) manganites are studied. A region with positive magnetic resonance around TFI is detected in samples with x=0.1 and 0.125. At this temperature the transition from the ferromagnetic-metallic (FM-M) phase to the ferromagnetic orbital ordered-insulating (FI) low-temperature phase occurs. This transition is accompanied by a substantial upward jump in resistance that appears on entering the FI phase. A jump in the magnetization, on crossing TFI downward, with respect to that measured in the FM-M phase is also detected.