RARE-EARTH AND TRANSITION-METAL SUBLATTICE CONTRIBUTIONS TO MAGNETIZATION AND MAGNETIC-ANISOTROPY OF R(TM,TI)(12) SINGLE-CRYSTALS

The substitution effect of Fe by Co on magnetic properties (magnetizat ion, anisotropy field, Curie temperature) of R(TM, Ti)(12) (R = Y, Sm; TM = Fe, Co) single crystals have been studied. The temperature and c omposition dependence of magnetization and magnetic anisotropy constan ts K-1 and K-2 in the range 77-1000 K have been determined using torqu e and vibrating specimen magnetometry techniques. Fe-57 Mossbauer spec tra of powdered samples of SmFe11-xCoxTi have been studied at room tem perature. The easy magnetization direction of RFe11-xCoxTi single crys tals was found to be coinciding with the c axis for x less than or equ al to 5. A characteristic maximum in concentration dependence of satur ation magnetization is found for x approximate to 3. The concentration dependence of magnetic anisotropy constant K-1 for RFe11-xCoxTi singl e crystals exhibited a maximum at x approximate to 1. It is found that the Sm-sublattice contribution to magnetic anisotropy decreases rapid ly with increasing Co concentration. (C) 1998 Published by Elsevier Sc ience S.A.