Large spontaneous volume magnetostriction and pressure effects on the magnetic properties of amorphous Ce-Fe alloys

Article abstract of DOI:10.1016/S0925-8388(96)02964-7

The thermal expansion anomaly, the effects of pressure and hydrogenation on the magnetization and the Curie temperature have been investigated in order to discuss the magnetovolume effects in the amorphous Ce_xFe_100-x alloys prepared by high-rate DC sputtering. These amorphous alloys have a large spontaneous volume magnetostriction which increases with decreasing x. The pressure effects on the magnetization, the spin freezing temperature and the Curie temperature are significant. The magnetization M varies linearly with the square of temperature T² in the ferromagnetic state. The hydrogenation increases markedly both the Curie temperature and the magnetization of the amorphous CeFe₂ alloy. However, no huge coercive force related to the random magnetic anisotropy has been confirmed at 4.2 K against the expectation based on a valence change of the Ce ion. For the amorphous CeFe₂ alloy, the compressibility estimated from the increases in the Curie temperature and the Fe-Fe interatomic distance by hydrogenation, does not coincide with the experimental value obtained by Brillouin scattering. Therefore, the expansion due to hydrogenation is not regarded to be caused by a so-called negative hydrostatic pressure effect.