Large temperature coefficient of resistance and magnetoresistance of La0.71Ca0.29Mn1-xCoxO3 polycrystalline ceramics

Abstract

La0.71Ca0.29MnO3 is a strongly correlated electronic material, which has been extensively researched and has high application value. It is known that improvements of the temperature coefficient of resistance (TCR) and magnetoresistance (MR), which are important parameters for the application of such materials, promote their applications. Using other elements to replace Mn sites is one of the methods to improve the specific properties. Herein, we prepare a series of La0.71Ca0.29Mn1-xCoxO3 (x = 0, 0.01, 0.03, 0.05, 0.1) polycrystalline ceramics via sol-gel method, and explore the effect of Co doping on the properties of La0.71Ca0.29MnO3. The results show that a small amount of Co doping can significantly improve TCR and MR. Under our excellent preparation process, TCR of La0.71Ca0.29MnO3 was 22.5%·K−1 and MR was 52.9% (under 1T magnetic field). When Co doping is 0.01, TCR reaches 35.1%·K−1 value and MR reaches 64.8%. This can provide critical information for the future application of such materials in bolometers and magnetic sensors.