Structural and magnetoelastic properties of Y_3Fe _(27.2)Cr_(1.8) and Ce_3Fe_(25)Cr_4 ferromagnetic compounds

摘要

The structural and magnetoelastic properties of polycrystalline samples of Y_3Fe_(27.2)Cr_(1.8) and Ce_3Fe _(25)Cr_4 intermetallic compounds are investigated by means of X-ray diffraction, thermomagnetic, thermal expansion and magnetostriction measurements in the temperature range of 77-500 K under applied magnetic fields up to 1.5 T. The well defined anomalies observed in the linear thermal expansion coefficient curves are associated with the magnetic phase transitions and presence of small amounts of 1:12 phase in the Ce_3Fe _(25)Cr_4 sample; the latter is also confirmed by AC susceptibility measurements. For Y_3Fe_(27.2)Cr_(1.8), saturation behavior is observed in the anisotropic magnetostriction isotherms near the magnetic ordering temperature (T_C), whereas for Ce _3Fe_(25)Cr_4 compound, saturation starts well below T_C. The additional anomalies observed in the volume magnetostriction isotherms of both compounds are explained based on the anisotropy field in the ab plane and along the c-axis of the unit cell.