Effect of a Uniaxial Stress on the Curie Temperature of a Single Crystal of Gd

The variation of the Curie temperature of a single crystal of Gd when subjected to a uniaxial stress up to 130 bar applied along the $c$ axis of the crystal, is (-1.55±0.05) × ${10}^{-3\mathrm{}}$ deg ${\mathrm{bar}}^{-1\mathrm{}}$. The rate of change with a stress applied along the $a$ or $b$ axis is (0±0.05) × ${10}^{-3\mathrm{}}$ deg ${\mathrm{bar}}^{-1\mathrm{}}$. The variations of the exchange interaction with the $a$, $b$, and $c$ crystallographic parameters are deduced, together with the variation of the Curie temperature with hydrostatic pressure, the magnetic length anomaly along the various crystallographic axes, and the anisotropic forced magnetostriction. The calculated values are in good agreement with the experimental values.