ABSTRACT La 0.67 Ca 0.33 MnO 3 is a typical perovskite manganese oxide material with rich physical properties, especially in the field of colossal magnetoresistance properties. La 0.67 Ca 0.33 MnO 3 : x Fe 3 O 4 (0 ≤ x ≤ 0.005) composite ceramics were prepared by sol–gel and solid‐phase methods to study the effect of Fe 3 O 4 addition on the electrical transport and magnetoresistive properties. The resistivity progressively increased with higher dopant content, while the metal–insulator transition temperature exhibited a systematic decrease with increasing composition fraction. Temperature coefficient of resistance (TCR) and magnetoresistance (MR) are considered key parameters for enabling practical applications of such ceramics. At x = 0.002, the TCR reached 37.32%·K −1 , representing an increase of 3.51%·K −1 compared with the pristine sample. At x = 0.003, the MR reached 61.49% (1 T), corresponding to an increase of 4.28% compared with the pristine sample. This series of results shows that the addition of Fe 3 O 4 to the composite ceramic can significantly increase the TCR and MR, which in turn can facilitate the potential applications of these materials in bolometers and magnetic sensors.
Yu et al. (Wed,) studied this question.