Structure-sensitive magnetic properties of YFe 6Al 6

Abstract

From magnetic studies on YFe 6Al 6 it was ascertained that both its Curie temperature and its magnetic moment are clearly dependent on thermal treatment (annealing at a temperature of 1073 K) and mechanical treatment (powdering). From tests performed it was concluded that when this alloy is rapidly cooled from the melting temperature the iron and aluminium atoms are statistically distributed in three non-equivalent crystallographic sites, i.e. 8i, 8j and 8f. This alloy is then ferromagnetic with a Curie temperature T c = 308 K and a magnetic moment of 8.4μ B per formula unit at 77.4 K. Annealing or powdering of such an alloy causes changes in the distribution of the iron and aluminium atoms in the crystal lattice (the iron atoms prefer the 8j and 8f sites), which has the effect of lowering the Curie temperature and reducing the magnetic moment of the alloy.