Study on crystallographic and magnetic properties of Y1-xDyxFe11Mo and Y1-xDyxFe11MoNy (x=0-1.0)

The variation in crystallographic and magnetic properties with Dy concentration has been investigated on Y1-xDyxFe11Mo and Y1-xDyxFe11MoNy compounds in detail. Lattice parameters a, c and saturation magnetization M-s at 1.5 K decrease while the Curie temperature T-c slightly increases with increasing Dy concentration in Y1-xDyxFe11Mo system. At room temperature, all Y1-xDyxFe11Mo samples exhibit a uniaxial anisotropy, and the anisotropy field decreases with increasing Dy concentration. Upon nitrogenation, the nitrides Y1-xDyxFe11MoNy retain the tetragonal structure symmetry of ThMn12 type with the addition of an expansion of about 4% on the unit cell volume. The Curie temperature and saturation magnetization at 1.5 K are drastically enhanced by nitrogenation. Unlike the parent alloy, YFe11MoNy shows a canted anisotropy at room temperature. But the other Y1-xDyxFe11MoNy. compounds with x greater than or equal to 0.2 have a uniaxial anisotropy which becomes stronger with increasing Dy concentration. (C) 1999 Elsevier Science B.V. All rights reserved.