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

In this work, we report the successful synthesis of a new intermetallic compound Dy2Ni0.87Si2.95 forming in single phase only with a chemically disordered structure. The random distribution of Ni/Si and crystal defects create a variation in the local electronic environment between the magnetic Dy ions. In the presence of both disorder and competing exchange interactions driven magnetic frustration, originating due to c/a approximate to 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 effects. In the magnetically short-range ordered region, much above the freezing temperature, an unusual occurrence of considerable magnetic entropy change, -SmaxM approximate to 21 J kg(-1) K-1 with large cooling power RCP approximate to 531 J kg(-1) and adiabatic temperature change, T-ad approximate to 10 K for a field change of 70 kOe, is observed for this short range ordered cluster-glass compound without any magnetic hysteresis loss.