Study on the existence and properties of Y3(Fe1−xCox)29−yCry (x = 0.6-1.0; y = 5-7) intermetallic compounds

The structural and magnetic properties of compounds with nominal composition Y3(Fe1−xCox)29−yCry (x = 0.6-1.0 and y = 5-7) have been investigated. The main phase formed was that of Nd3(Fe,Ti)29-type structure (3:29) with a significant amount of a disordered variant of the hexagonal Th2Ni17-type structure (2:17H) as a secondary phase (25-50 wt.%), especially for higher Co (80% and above) content. The unit cell volume is decreasing with the increase of the Co and Cr content, as well as all the cell parameters. The Curie temperature of both phases decreases monotonically with x and y. The x = 1.0 compound is paramagnetic at room temperature. The x = 0.6, 0.8 compounds present uniaxial anisotropy along the [2 0 4] direction of the monoclinic Nd3(Fe,Ti)29-type structure, which should be attributed to the transition metal sublattice. The saturation magnetization and the anisotropy field are lower in the sample with x = 0.8 compared to the one with x = 0.6. This reduction is also observed in the Mössbauer spectra of the materials at room temperature which are also presented.