Influence of doping elements (Y, Fe, V) on magnetic properties of RM sub(2) (R= Gd, Er; M= Fe, Co, Ni) Laves phases and their hydrides

The ternary R sub(0.85)Y sub(0.15)Ni sub(2), RNi sub(1.85)Fe sub(0.15) (R=Gd and Er), ErM sub(1.85)V sub(0.15) (M=Fe, Co) and Er(Fe,Co) sub(1.85)V sub(0.15) phases have been investigated for the influence of doping elements (Y, Fe, V) on magnetic properties of RM sub(2) (R=Gd, Er; M=Fe, Co, Ni) Laves phases and their hydrides. All investigated compounds can easily absorb hydrogen up to 3.3-3.9 at.H/f.u. at 0.1-0.12 MPa pressure without amorphization. The hydrides preserve the structure of the parent compounds. Rare earth substitution of Gd and Er by 5 at. % Y in RNi sub(2) based compounds reduces slightly both the ordering temperature and the magnetic moment due to the dilution effect of a magnetic rare earth element by a nonmagnetic one. The corresponding 3d metal substitution of Ni by 5 at. % Fe increases T sub(C) by a factor of 3-7 for Gd and Er, respectively. Er(Fe,Co,V) sub(2) compounds with a Fe content higher than 20 at. % exhibit ordering temperatures above room temperature. Hydrogen absorption reduces the saturation moment and suppresses long range magnetic order in majority of investigated alloys to the temperature below 2 K except for ErFe sub(1.85)V sub(0.15)H sub(3.9) and ErFe sub(0.925)Co sub(0.925)V sub(0.15)H sub(3.6).