Magnetism and magnetocaloric effect in YNi<inf>4</inf>Si-type RNi4Si (R=Ce, Gd, TB and DY) compounds

Magnetic properties and magnetocaloric effect of YNi4Si-type RNi4Si (R=Ce, Gd, Tb and Dy) compounds have been investigated. Magnetic measurements indicate the intermediate valence state of cerium in YNi4Si-type CeNi4Si. The magnetocaloric effect of GdNi4Si, TbNi4Si and DyNi4Si are calculated in terms of isothermal magnetic entropy change and they reach maximum values of -22.9 J/kg K, -13.5 J/kg K and -15.6 J/kg K for a field change of 140 kOe near ∼28 K, 47 K and 27 K and they show maximum values of -12.7 J/kg K, -7.8 J/kg K and -9.3 J/kg K for a field change of 50 kOe near ∼28 K, 42 K and 22 K, respectively. In contrast to GdNi4Si, the magnetization-field isotherms for TbNi4Si and DyNi4Si exhibit hysteresis loop at 2 K due to strong magnetocrystalline anisotropy.