Compositional dependence of the magnetocaloric effect in La1-xCaxMnO3 (0≤x≤0.52) -: art. no. 094403

A detailed investigation of the thermodynamic properties of La1-xCaxMnO3 (0less than or equal toxless than or equal to0.52) for possible applications in magnetic refrigeration is presented. The adiabatic magnetic entropy change \DeltaS\ is determined for a 2 Tesla change in magnetic field using magnetization measurements. A broad double peak behavior as a function of x is observed with maximum absolute values \DeltaS\(max) near 5.5 J/kg K for xapproximate to0.28. The largest \DeltaS\(max) values do not coincide with the maximum value of the ferromagnetic transition temperature T-c. The relatively large adiabatic magnetic entropy change is moderated by a large heat capacity, which leads to a modest adiabatic temperature change of about 2 K for the x=0.28 specimen. The largest contribution to \DeltaS\(max) occurs for magnetic field changes in the range 0less than or equal toHless than or equal to2 Tesla; increasing the magnetic field range to 3 Tesla only increases \DeltaS\(max) by about 20%.