MAGNETIC-DOMAIN STRUCTURE OF NI1-XMNX FILMS INFERRED FROM RESISTANCE FLUCTUATIONS

In films of partially ordered Ni1-xMnx with x almost-equal-to 0.28, large electrical-resistance noise from magnetic effects was found. Individual fluctuating domains with large volumes but low magnetic moments were observed. These domains are apparently clusters of constituent ferromagnetic domains which have a net systematic antiferromagnetic alignment. The clusters are larger in the ''reentrant spin-glass'' regime than in the ferromagnetic regime. Ferromagnetic domains arranged in antiferromagnetic stripes were also imaged by scanning electron microscopy.