Abstract:
The influence of partial substitution of Laby Dy on the magnetocaloric response of(La1 xDyx)0.67-Ca0.33Mn0.9V0.1O3, where x¼0.03, 0.15and0.25 is studied.Rietveld refinement ofX-ray diffraction pattern using GSAS method shows that the compounds adopt the orthorhombic structure with Pnma space group.The systematic change in lattice parameters and magnetic phase transition indicates the substitution effect of Dy.From the magnetization isothermsat different temperatures,magnetic entropy change close to their respective transition temperatures(TC) hasbeenevaluated.The
maximum value of entropy change near TC is found to be about 4.8J/kgKat187.5KforLCMVDy0.03,2.45 J/kgKat107.5KforLCMVDy0.15 and 2.15J/kgKat92.5KforLCMVDy0.25 at 4T. Dy addition produces are duction in TC and in magnitude of themagnetic entropychange. Eventhough the entropy change decreases with increasing Dy substitution therefrigerant temperaturerange, DT, is found to be
10 KforLCMVDy0.03, 31KforLCMVDy0.15 and 35KforLCMVDy0.25 compounds[90%]at4T.The field
dependence of the magnetic entropy change is also analyzed showing the power law dependence,DSMNHn where n¼0.75(2)forLCMVDy0.03, n¼0.80(4) for LCMVDy0.15 and n¼0.92(8)forLCMVDy0.25
compounds at their respective transition temperatures.There lative cooling power and its field dependance are also analyzed
