Optimizing magnetic ordering temperature of magnetocaloric rare earth intermetallic compounds RNi: The case of multicomponent Gd0.2Tb0.2Dy0.2Ho0.2Er0.2Ni

Magnetic and magnetocaloric properties of multi-component rare earth intermetallic compound Gd _0.2Tb _0.2Dy _0.2Ho _0.2Er _0.2Ni has been studied in applied magnetic fields up to 70 kOe. Polycrystalline Gd _0.2Tb _0.2Dy _0.2Ho _0.2Er _0.2Ni has orthorhombic FeB-type crystal structure at 300 K (space group Pnma, no. 62, oP8) and orders ferromagnetically at ∼66 K (T _C). Magnetization vs field isotherms have been measured around T _C and also the temperature dependence of heat capacity in zero magnetic field. Using these data, isothermal magnetic entropy change (ΔS _m) and adiabatic temperature change (ΔT _ad) near the ferromagnetic transition are estimated. A normal magnetocaloric effect with a maximum ΔS _m value of −16.4 J kg ⁻¹ K ⁻¹ and ΔT _ad value of 6.2 K is obtained for 70 kOe field change at 62.5 K. Magnetocaloric effect is moderate when compared to that in the parent RNi (R = Gd, Tb, Dy, Ho and Er) compounds. A relative cooling power of ∼930 J/kg is obtained for 70 kOe field change for the Gd _0.2Tb _0.2Dy _0.2Ho _0.2Er _0.2Ni sample.