Magnetic inhomogeneities inherent to spin systems with quenched random-exchange disorder

A critical assessment of theoretical models proposed in the literature for the spin structure in amorphous Fe100–xZrx alloys (a three-dimensional ferromagnet with quenched random-exchange disorder which exhibits a re-entrant behaviour at low temperatures), based on a detailed comparison between theoretical predictions and available experimental results, is presented. The infinite ferromagnetic matrix plus finite ferromagnetic spin clusters model, originally proposed by the author, is shown to provide a coherent basis for understanding the nature and origin of magnetic inhomogeneities in this system.