Impact of the transition metal ion-doped on the electrical and magnetic properties of La0.67Ca0.33MnO3Ag0.15-based polycrystalline ceramics

Abstract

• High quality La 0.67 Ca 0.33 Mn 0.98 B 0.02 O 3 :Ag 0.15 ceramics were prepared by sol–gel route. • The transition metal ion doping can enhance the MR peak effectively. • The highest TCR peak of 75.4%·K −1 and highest MR peak of 87.0% by Fe doping was obtained. In this work, high-quality La 0.67 Ca 0.33 MnO 3 :Ag 0.15 and La 0.67 Ca 0.33 Mn 0.98 B 0.02 O 3 :Ag 0.15 (B = Fe, Co, Ni) ceramics were prepared by the sol–gel route. The slight substitution of the Mn sites has significantly affected the metal–insulator transition and the ferromagnetic–paramagnetic transition. The Mn site doping leads also to a decrease in the temperature of the metal–insulator transition, an enhancement in resistivity, and a reduction in the saturation magnetization. More specifically, the Fe doping approach can significantly increase the peak temperature coefficient of resistance ( TCR peak ), since the TCR peak increases from 62.5%·K −1 to 75.4%·K −1 . In addition, Fe, Co, and Ni doping can effectively elevate the peak magnetoresistance ( MR peak ), of which the modification induced by Fe is the most significant since it enhances from 71.5% to 87.0%. Both the TCR peak and MR peak obtained are the highest in the current study, which can greatly promote the application of the manganate materials in the field of infrared detection and magnetic sensitivity.