Bloch Relation Research Articles

Spin wave stiffness constant of amorphous (Co 1− xNi x) 75Si 10B 15 alloys

We report here the spin wave stiffness constants of amorphous (Co 1− x Ni x ) 75Si 10B 15 (0.1 ⩽ x ⩽ 0.5, x increases in steps of 0.1) alloys obtained from the low temperature magnetization curves and spectroscopic splitting g factors. The low temperature dependence of the magnetization was measured with a superconducting quantum interference device magnetometer and the g values were derived from ferromagnetic resonance measurements. The g values increase with increasing Ni content. The temperature dependence of magnetization is in good agreement with Bloch's relation M s (T) = M s (0)(1 − BT 3 2 − CT 5 2 ) at low temperatures, and the spin wave stiffness constants become smaller with the addition of Ni.

Magnetic properties of amorphous (Fe−1xNix)75Si10B15 alloys

Abstract Amorphous (Fe1−xNix)75Si10B15 (0.1 ⩽ x ⩽ 1, the step of x is 0.1) alloys were preparedby the rapid quenching technique and their magnetization measurements have been performed by utilizing a vibrating sample magnetometer from 77 K up to 800 K. The Curie temperature, Bloch coefficient, and range of exchange interaction were calculated from the temperature-dependent saturation magnetization curves. The low temperature dependence of magnetization is in good agreement with Bloch's relation, M s (T) = M s (0) (1 - BT 3 2 - CT 5 2 ) . The range of exchange interaction becomes shorter with the addition of nickel concentration. The observed mean square ranges of exchange interaction shows that this alloy system loses the ferromagnetic ordering when x is larger than 0.9.