This test method covers the measurement of the ferrimagnetic resonance linewidth and gyromagnetic ratio of isotropic microwave ferrites. This test is restricted to spherical specimens possessing resonance linewidths greater than 10 Oe [796 A/m]. The values and equations stated in customary (cgs-emu and inch-pound) or SI units are to be regarded separately as standard. Within this standard, SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with this standard.This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.