Electron spin resonance absorption in paramagnetic colloidal suspensions has been investigated both theoretically and experimentally. The nature and shape of the spectra are determined by the Brownian rotation of the particles. A magnetic field tends to align magnetically anisotropic particles so that the direction of maximum magnetic susceptibility in the particles is along the field. The alignment is resisted by the Brownian rotation of the particles. The temperature dependence of the angular distribution function, which is determined from simple statistical resaoning, has been confirmed experimentally in a quantitiative manner. From a comparison of computed and experimental spectra it is possible to determine a mass average mass of the particles. The equivalent of singlehyphen;crystal spectra can be obtained by freezing a suspension in a strong magnetic field. Angular variation studies of the spectra can then be carried out as with any single crystal. Consequently, accurate values ofAperp;andverbar;thinsp;gxthinsp;minus;thinsp;gythinsp;verbar;can be determined, which is not usually possible from powder spectra.
展开▼
