Magnetic properties of GdFe sub 11-x Si sub x Ti

• Published in: Journal of alloys and compounds Vol. 345; no. 1-2; pp. 27 - 35
• Main Authors: Cizmas, C B, Djega-Mariadassou, C, Bessais, L
• Format: Journal Article
• Language: English
• Published: 28.10.2002
• ISSN: 0925-8388

Induction melted GdFe sub 11-x Si sub x Ti alloys (x < = 2) with ThMn sub 12 -type structure have been investigated by X-ray diffraction, weak field thermomagnetometry from 300 to 850 K and isotherm magnetization measurements in magnetic fields up to 5.5 T from 4.5 to 300 K. The unit-cell volume decreases with increasing Si content. The reduction of the Curie temperature is correlated to the decrease of the Fe sublattice ordering temperature deduced from the Curie temperature of the homologous YFe sub 11-x Si sub x Ti series. The exchange coupling parameters were derived in the approximation of the molecular field. Their increase with x gives evidence for an enhancement of the indirect 3d-4f interaction via 5d which results from the 3d-5d hybridization favored by the Si substitution. The magnetocrystalline anisotropy of aligned and fixed polycrystalline samples was deduced from the fits of the M sub perpendicular (H) isotherms in the assumption of a Gaussian distribution of easy axis around the alignment direction. The anisotropy constants K sub 1 , K sub 2 and the anisotropy field H sub A decrease with increasing temperature. The Si substitution is responsible for a reduction of K sub 1 but K sub 2 , which increases slightly at low temperature, appears more sensitive to the exchange interaction Fe-Fe.