Magnetostriction and thermal expansion of Er2Fe14B and its hydride

Abstract The magnetostriction and thermal expansion of the Er 2 Fe 14 BH x ( x = 0 , 2.5) intermetallic compounds were investigated. Measurements were carried out by the strain-gauge method in the temperature range 77–420 K in magnetic fields up to 1.2 T. It was found that the longitudinal magnetostriction λ ∥ ( T ) of the host compound significantly increases in value in the temperature range 320–365 K that mainly connected with the contribution of the Fe-sublattice to the total magnetostriction of the Er 2 Fe 14 B. The temperature dependencies of the linear thermal expansion coefficient α ( T ) measured for the Er 2 Fe 14 B compound and for its hydride Er 2 Fe 14 BH 2.5 have anomalies in the range of the spin-reorientation transition (SRT). It has been shown that Er 2 Fe 14 B compound has an invar effect in the temperature range 77–280 K.