Specific heat and resistivity of a double-exchange ferromagnetLa0.7Ca0.3MnO3

Abstract

We have measured the specific heat and resistivity of mixed valence manganite ${\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_3$ as a function of temperature and magnetic field. We demonstrate that the magnetic contribution to the specific heat in this system is proportional to the temperature coefficient of the resistivity in the magnetic phase transition region, following the Fisher-Langer relation. This suggests that a sharp drop in the resistivity of ${\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_3$ in the transition region is due to the reduction in magnetic scattering.