Magnetocaloric effect and temperature coefficient of resistance of La2/3(Ca,Pb)1/3MnO3

Abstract

The magnetocaloric effect of a La2/3(Ca,Pb)1/3MnO3 single crystal was examined. From the measurements of isothermal magnetization and heat capacity around the Curie temperature, we have calculated the maximum isothermal magnetic entropy change as ∼7.5 J/kg K and the adiabatic temperature changes as ∼5.6 K, near room temperature for a 7 T magnetic field variation. Besides, the sharp drop of resistivity at the insulator–metal transition associated with the magnetic transition gives rise to a large temperature coefficient of resistance (TCR). For the La0.7Ca0.3MnO3 and La2/3(Ca,Pb)1/3MnO3 single crystal, the peak of TCR is ∼50%/K at 218 K and ∼10%/K at 290 K, respectively.