Spin-waves in nickel, iron, and yttrium-iron garnet

Abstract

The magnetostatic properties of single crystals of nickel, iron, and yttrium-iron garnet have been measured along the three crystallographic axes, in magnetic fields up to 180 000 Oe and at different temperatures between 4.21 and 286 K. The relative accuracy is 0.01%. It is found that the magnetization values as a function of the internal magnetic field satisfy the Holtstein-Primakoff test. A method to determine the spontaneous magnetization is given. The magnetization curves are interpreted in terms of the spin-wave theory; a superimposed susceptibility is determined for nickel and iron.