The enhancement of electromagnetic properties of La0.8Sr0.2MnO3 at room temperature by Fe3+ doping

A series of La 0.8 Sr 0.2 Mn 1- x Fe x O 3 ( x  = 0–0.03) ceramic materials were synthesized via the sol–gel method, and their structural, electrical, and magnetic properties were systematically investigated. Rietveld refinement of X-ray diffraction (XRD) patterns reveals that all LSMFO ceramics crystallize in a rhombohedral perovskite structure (space group: R 3 ¯ c ). Scanning electron microscopy (SEM) analysis demonstrates that appropriate Fe doping ( x  = 0.01) can promote grain growth. With the increase of Fe doping content, both the temperature coefficient of resistance (TCR) and magnetoresistance (MR) of LSMFO samples exhibit a trend of first increasing and then decreasing. For the sample with  x   = 0.005, the TCR and MR reach their maximum (TCR peak and MR peak ) values: 6.48%·K −1 (peak TCR temperature T k  = 301.48 K) and 27.06% (peak MR temperature T m  = 304.21 K), respectively, with both corresponding temperatures close to room temperature. The optimization of electrical and magnetic properties of LSMFO samples is attributed to the improvement of grain boundary density and grain size by Fe doping. In summary, these results demonstrate that LSMFO ceramics hold broad application prospects in fields such as uncooled infrared bolometers and magnetic sensors.