MAGNETIC STUDIES OF AMORPHOUS NI-P ALLOYS

Magnetization studies were performed on amorphous Ni100-xP(x) alloys with 15 less-than-or-equal-to x less-than-or-equal-to 23 in the temperature range from 4.2 to 300 K and in fields up to 9 kOe. Samples with x < 17 were prepared by electrodeposition, whereas samples with x greater-than-or-equal-to 17 were obtained by either electrodeposition or melt-quenching. The conduction electron susceptibility of the latter samples showed to be independent of the preparation method. Furthermore, the magnetic behaviour was found to differ strongly for x less-than-or-equal-to 17 and x greater-than-or-equal-to 17. These different magnetic properties are attributed to a change in the size and behaviour of the magnetic inhomogeneities embedded in the Ni-P matrix: for x greater-than-or-equal-to 17, they can be described as giant-moment paramagnetic clusters, whereas for x less-than-or-equal-to 17 they form superparamagnetic particles.