Influence of Sr-doping on the metal-insulator transition temperature and magnetoelectric properties of La0.67Ca0.33Mn0.98V0.02O3 polycrystalline ceramics

The excellent temperature coefficient of resistance (TCR) and magnetoresistance (MR) exhibited by the La-Ca-Mn-O system make it a good candidate for devices such as infrared detectors, attracting the attention of a large number of researchers. However, its metal-insulator transition temperature (T-P) is far from room temperature, which greatly limits its application. Due to the high tolerance of the material system, A-site doping is considered an effective method to improve the above properties. In this study, high-quality La0.67Ca0.33-xSrxMn0.98V0.02O3 (x=0.00, 0.01, 0.02, 0.03, 0.04) series polycrystalline ceramics were synthesized by the sol-gel method, and the T-P of the material system was increased by nearly 40 K by Sr-doping, and the introduction of Sr effectively reduced the resistivity of the ceramics. Sr2+ gradually replaced Ca2+, the ionic radius increased, the double exchange effect was enhanced, which eventually leads to the increase of T-P.