La-Ca-Mn-O thin film based thermistor for measuring low temperature of 77-230 K

Perovskite manganite La-Ca-Mn-O (LCMO) thin films were deposited on LaAlO3 (001) single crystal substrate by radiofrequency magnetron sputtering at ro om temperature. After annealing at 800-1000 degrees C in O-2 atmosphere for 1 h, sheet resistance (R) of the LCMO thin films was measured by van der P auw method in the range of 77-300 K. The characteristic resistance-temperat ure curves of all the annealed films showed typical insulator to metal tran sition behavior of colossal magnetoresistance (CMR) materials on cooling. T he sheet resistance of LCMO films changes with temperature, conforming to a function of exp(beta T) in the temperature range from 77 K to 230 K, which is applicable to an oxide thin film thermistor.