MAGNETIC-PROPERTIES OF SM2FE14-XCOXSI2-BASED QUASI-TERNARY COMPOUNDS

The structural and magnetic properties of the off-stoichiometric R(2)F e(17)-type Sm2Fe14-xCoxSi2 compounds with 0 less than or equal to x le ss than or equal to 7 have been investigated by x-ray diffraction, the rmomagnetic analysis, and magnetic measurements. Substitution of Co fo r Fe leads to an increase in Curie temperature, Delta T-c=303 K for sa mples with x from 0 to 7. The saturation magnetization M(s) increased with increasing Co content at first and then decreased. A maximum satu ration magnetization M(s)=124 emu/g was obtained at x about 4. The ani sotropy changes from planar x<4 to uniaxial x greater than or equal to 4 with H-a=23 kOe for x=7. Introduction of N leads to an increase in lattice constants causing a further enhancement in the Curie temperatu re and anisotropy field. The best properties were obtained for the Sm2 Fe10Co4Si2N23 compound with T-c=742 K, H-a (300 K)=175 kOe.