METHOD FOR DETERMINING SIZE OF FERROMAGNETIC PARTICLES Russian patent published in 1996 - IPC

FIELD: measurement technology. SUBSTANCE: method involves placing an object under study in permanent magnetic field and exposing it to microwave frequency radiation, measuring magnetic field magnitude, measuring radiation characteristic after its interaction with magnetic liquid took place and determining the parameter to be found. The magnetic liquid is exposed to microwave frequency radiation on working and auxiliary frequencies. Magnetic field magnitude is selected to be enough for ferromagnetic resonance to take place. Magnetic field strength is changed smoothly at the mentioned frequencies, strength values are recorded corresponding to microwave frequency wave reflection coefficient values. Ferromagnetic resonance curve breadth is calculated. Microwave frequency radiation frequencies are selected from a range in which ferromagnetic resonance curve breadth ratio with respect to frequency remains constant. Working frequency is selected from a range where this ratio varies with frequency. The particle size of interest is determined from a suggested formula. EFFECT: enhanced accuracy of measurements. 2 dwg, 1 tbl