Effect of pressure on the spontaneous volume magnetostriction of GdAl2

The thermal expansion and lattice constants of polycrystalline GdAl2 have been measured under high pressure. It is found that as pressure increases, the Curie temperature TC increases with a ratio of ∂TC/∂P=8.56  K/GPa and the spontaneous volume magnetostriction ωs decreases rapidly. C15 structure is stable up to 12.4 GPa and the bulk modulus is 75.3 GPa at room temperature. Grüneisen parameter of TC is estimated to be 3.84. Using these experimental results, the pressure dependence of TC is discussed on the basis of the itinerant electron model of ferromagnetism.