Magnetocaloric effect in RMnO3 (R=Gd, Tb and Dy) multiferroics

Multiferroic materials with the compositional formula RMnO3 (where R=Gd, Tb and Dy), were prepared by the citrate gel technique. After characterizing the samples structurally, a systematic investigation of specific heat has been undertaken, over a temperature range 4-300 K at different magnetic fields. All the samples display interesting specific heat behavior exhibiting transitions due to the long range ordering of Mn3+ and R3+ moments. Magnetic field change generates an entropy change of ~1 J/mol K when a magnetic field changes from 0 to 5 T in the vicinity of antiferromagnetic ordering temperature of R3+. The value of adiabatic temperature change ~3 K for a field of 5 T is also appreciable to consider these materials as possible magnetic refrigerants at low temperatures.