Nitrogen-bearing amorphous Fe83−xVxB14Si3 alloys: Thermal and magnetic properties

Magnetic properties of amorphous alloys Fe83−xVxB14Si3 containing 0.02–0.85 at. % nitrogen have been studied from 4 K to the crystallization temperatures. The effect of vanadium in these alloys is to decrease the ferromagnetic transition temperature TC at 23 K/at. % V, as well as the magnetization σ at 8.8 (emu/gm)/at. % V. This indicates loss of ferromagnetism in this alloy system for V concentrations greater than 26 at. %. The addition of nitrogen increases crystallization temperature Tx, saturation magnetization, and spin wave exchange stiffness constant D. The observed T-dependence of the magnetization over the entire temperature range 4–300 K, can be described only by taking into account both the T3/2 and T5/2 terms. This is unlike the normal extended T3/2 behaviour observed in amorphous alloys having TC above room temperature.