Effect of hydrogenation on magnetostriction and magnetocaloric effect in gadolinium single crystal

The gadolinium single crystal obtained by the Czochralski method was hydrogenated to the composition GdH$_{0.15}$, which corresponds to a metal–hydrogen solid solution ($\alpha$ phase). The magnetostriction and magnetocaloric effect were measured for both the initial and hydrogenated samples. It is found that the hydrogen atoms in the hexagonal lattice of gadolinium can affect the magnitude and sign of the magnetostriction constants and cause the anisotropy of the magnetocaloric effect. The main mechanisms responsible for the observed effects are discussed.