Magnetic and universal magnetocaloric behavior of rare-earth substituted DyFe0.5Cr0.5O3

We report the effect of partial substitution of Dy-site by rare-earths (R=Gd, Er and La)on the magnetic and magnetocaloric behavior of a mixed metal oxide DyFe0.5Cr0.5O3.Structural studies reveal that substitution of Dy by R has a minimal influence on the crystal structure. Magnetic and heat capacity studies show that the magnetic transition around 121 K observed for DyFe0.5Cr0.5O3 remains unchanged with rare-earth substitution, whereas the lower magnetic transition temperature is suppressed/enhanced by magnetic/non-magnetic substitution. In all these compounds, the second order nature of magnetic transition is confirmed by Arrott plots. As compared to DyFe0.5Cr0.5O3, the values of magnetic entropy change and relative cooling power are increased with magnetic rare-earth substitution while it decreases with non-magnetic rare-earth substitution. In all these compounds, magnetic entropy change follows the power law dependence of magnetic field and the value of the exponent n indicate the presence of ferromagnetic correlation in an antiferromagnetic state. A phenomenological universal master curve is also constructed for all the compounds by normalizing the entropy change with rescaled temperature using a single reference temperature. This master curve also reiterates the second order nature of the magnetic phase transition in such mixed metal oxides.

Mohit K. Sharma, K. Mukherjee · 2017