Effect of hydrogen insertion on the magnetic properties of Er(Fe,Co)11Ti single crystals

Magnetocrystalline anisotropy and spin-reorientation transitions (SRT) of the ErFe11−xCoxTiHy (x=0, 2, 4; y=0, 1) compounds with the ThMn12-type structure were studied. The investigation of ErFe11−xCoxTiHy compounds with x≤2 show an “easy axis” anisotropy at room temperature and an “easy cone” anisotropy at temperatures below the spin-reorientation temperature (TSR). The ErFe7Co4Ti with x=4 below the SRT exhibits an “easy plane” anisotropy with the easy direction oriented along the [1 0 0] axis. Hydrogen insertion into ErFe9Co2Ti leads to an increase of TSR whereas hydrogenation of ErFe7Co4Ti causes TSR decreasing down to 40 K and essential change of SRT character. ErFe7Co4TiH hydride has an “easy cone” anisotropy below TSR. It was found that the replacement of the Fe by Co and hydrogen insertion into the crystal lattice of Er(Fe,Co)11Ti compounds has an opposite influence on the SRT temperature.