Room-temperature magnetic entropy change in La0.7Sr0.3Mn1-xMxO3 (M = Al, Ti)

Magnetic entropy change in and above the room‐temperature region has been measured for La0.7Sr0.3Mn1‐x Mx O3 (M = Al, Ti) by means of magnetization measurements in magnetic fields up to 6 T. The magnetocaloric effect (MCE) becomes strongest at the Curie temperature Tc that is tuned to ∼300 K by the substitution of Al or Ti for Mn. While the substitution of Al for Mn drastically reduces the entropy change, it extends considerably the working temperature span and improves the relative cooling power (RCP). The MCE and RCP seem to be only lightly affected by Ti substitution. Although manganites are considered potential for magnetic refrigerants, the limitations for achieving strong MCE in the materials are also discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)