Microwave Measurement of Saturation Magnetization of Ferrites

A microwave method of measurement of 4¿Ms, for high-resistivity materials such as ferrites and garnets is described. The method employs the ferromagnetic resonance absorption of microwave energy, and the shape-dependent demagnetization effects as given by Kittel´s equation to evaluate 4¿Ms. Effects of specimen shape and position are analyzed, and the superiority of a method employing two pieces in the waveguide is pointed out. The advantages of these techniques over the usual magnetometer methods are compatibility with measurements on other parameters, ease of shaping the specimen, avoidance of calibration procedures and simplicity of setup. In particular, this method is the most convenient for ferrite thin films.