Physical Chemistry Chemical Physics 2018-04-13

Observation of short range order driven large refrigerant capacity in chemically disordered single phase compound Dy2Ni0.87Si2.95

Santanu Pakhira, Chandan Mazumdar, Dibyasree Choudhury, R. Ranganathan, Saurav Giri

Index: 10.1039/C8CP01280F

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Abstract

In this work, we report the successful synthesis of a new intermetallic compound Dy2Ni0.87Si2.95 forming in single phase only with chemically disordered structure. The random distribution of Ni/Si and crystal defects create a variation in the local electronic environment between the magneticDy ions. In the presence of both disorder and competing exchange interactions driven magnetic frustration, originating due to c/a∼ 1, the compound undergoes spin freezing behaviour below 5.6 K. In the non-equilibrium state below the spin freezing behaviour, the compound exhibits aging phenomena and magnetic memory effect. In the magnetically short-range ordered region, much above the freezing temperature, an unusual occurrence of considerable magnetic entropy change, -ΔSMmax ~ 21 J/Kg-K with large cooling power RCP ~ 531 J/kg and adiabatic temperature change, ΔDTad~ 10 K for a field change of 70 kOe, is observed for this short-range ordered cluster-glass compound without any magnetic hysteresis loss.