Magnetism and Local Environment Model in (Ni/sub 1-C/Co/sub C/) sub 0sub 78 p sub 0sub 14 B sub 0sub 08Amorphous Alloys.

摘要

The magnetic properties of amorphous alloys (Ni/sub 1-c/Co/sub c/) sub 0 . sub 78 P sub 0 . sub 14 B sub 0 . sub 08were investigated. The samples were prepared by the splat-cooling method. The Curie temperatures were determined and the magnetization measurements,performed for 1.7exp 0 K less than or equal to T less than or equal to 270exp 0 K and fields up to kOe. Ni sub 0 . sub 78 P sub 0 . sub 14 B sub 0 . sub 08is paramagnetic,whereas Co sub 0 . sub 78 P sub 0 . sub 14 B sub 0 . sub 08is ferromagnetic until the crystallization temperature (678exp 0 K). The average moment per cobalt atom is 1.15mu /sub B/. In (Ni/sub 1-c/Co/sub c/) sub 0 . sub 78 P sub 0 . sub 14 B sub 0 . sub 08the critical concentration for the paramagnetic-ferromagnetic transition is c approximately equal to 0.15;this transition occurs in an inhomogeneous way. The saturation magnetization in the whole concentration range can be interpreted (as for some crystallized alloys and compounds) by a local environment model,when a reasonable short-range order is assumed. In such a model the magnetic moment per cobalt atom is related merely to the number of its Co first neighbors n/sub Co/. For n/sub Co/ = 0and 1the cobalt atom is not magnetic,for n/sub Co/ = 2and 3it carries a small moment mu sub 1 = 0.50mu /sub B/and for n/sub Co/greater than 3it is magnetic with mu sub 2 = 1.15mu /sub B/as in Co sub 0 . sub 78 P sub 0 . sub 14 B sub 0 . sub 08 ;the nickel atoms do not carry a substantial moment in the entire concentration range. These features are comparable to those obtained in some crystalline alloys. 3figures. (ERA citation 02:049173)