Magnetic and transport behaviors of La0.5(Sr0.53Ca0.47)0.5MnO3 under pressure, magnetic field, and Fe doping

Abstract

Effects of pressure, magnetic field, and Mn-site doping on the magnetic structure and resistive behavior of La0.5(Sr0.53Ca0.47)0.5Mn1−xFexO3 (0⩽x⩽0.10) have been experimentally studied. The system experiences two magnetic transitions subsequently with decreasing temperature: a paramagnetic to ferromagnetic transition and a ferromagnetic to antiferromagnetic (AFM) transition. The second magnetic transition coincides with a steep resistivity jump. In addition to reducing the critical temperature for the AFM transition (TN), the incorporation of Fe enhances the ferromagnetic order below TN as demonstrated by the gradual increase of magnetization with the content of Fe. Long-range AFM order is replaced by short-range AFM order when x exceeds 0.03, and disappears completely for x>0.06. The application of pressure or magnetic field depresses the AFM nature of the compounds, resulting in a downward shift of TN at a rate of ∼7 K/GPa or ∼4 K/T. The most interesting observation of the present study is the greatly enhanced resistivity jump at TN, which increase from 1 to 2 orders, after the sample undergoes a pressurizing and then a pressure relieving process. Although high pressure, magnetic field, and Fe doping produce similar effects on the AFM order, the underlying physics is different.