ROLE OF INTERFACES IN CHANGES OF MAGNETIC-PROPERTIES AND MAGNETORESISTANCE OF ALFENOL-16

Influence of interfaces, predominantly grain boundaries and high dislo cation density regions, on magnetic properties (parameters of hysteres is loops and Mossbauer spectra) and magnetoresistance, is studied on t he Alfenol 16 alloy. The amount of interfaces was changed by heat and mechanical treatments. Hysteresis loops differ in polarization values near the saturation as well as in shape. In the samples with D0(3) sup erstructure hard approach to saturation indicates ferrimagnetic like b ehaviour. Changes in the low field part of magnetoresistance curves de pend on kind and amount of interfaces: conduction electrons scatter on domain walls being closely bound to interface objects. The slope of t he magnetoresistance curve for high fields is in correlation with the degree of D0(3) order: Al atoms occupying lattice positions out of the D0(3) order disturb the spin orientation. It increases the resistivit y, in comparison with other centres of scattering of conduction electr ons removable by external field, quite substantially.