UDC

538.955

Authors

Koposov Gennadiy Dmitrievich
Institute of Natural Sciences and Biomedicine, Northern (Arctic) Federal University named after M.V. Lomonosov (Arkhangelsk, Russia)
e-mail: fc.genphys@pomorsu.ru
Sofronov Evgeniy Leonidovich
Institute of Natural Sciences and Biomedicine, Northern (Arctic) Federal University named after M.V. Lomonosov (Arkhangelsk, Russia)
e-mail: e.sofronov@narfu.ru

Abstract

The paper summarizes the results of the experimental studies of diaparamagnetic phase transition in dispersed medium. Research technique is based on the Gouy method for measuring the magnetization and magnetic susceptibility of weakly magnetic materials using the torsion balance and the special chamber for low temperature measurements. The features of the field, humidity and temperature dependences of the magnetic susceptibility and magnetization composing the experimental basis for constructing a theory of this phenomenon are described. The field dependences indicate nonlinearity between the magnetization and magnetizing force and are similar to the ferromagnetics specific dependencies. Very high values of the magnetic susceptibility can’t explain the phenomenon, taking into account only the paramagnetism of unpaired surface electrons within the frame of the classical model of paramagnetism. Noncompliance with the Curie’s law is observed for the temperature dependences of magnetic characteristics. Injection of moisture in the dispersing medium leads to a decrease of the magnetic characteristics. The samples of quartz powder discovered the effect of increasing the magnetic susceptibility with increasing temperature above 0 °C, unexplained in the framework of the classical theory. The nature of the spin paramagnetism of dispersed structures and the cooperativity evidence in the paramagnetism formation is established in the article. Spin paramagnetism is stipulated by the appearance of unpaired spin magnetic moments due to the electron-pair bond rupture at the moment of dispergating. Bond rupture occurs as on the surface of the dispersion medium granules, and within the scope of the granules in the amorphization of the crystal structure process. The cooperativity is manifested in the appearance of magnetic clusters with parallel oriented spins as a result of spin-spin interaction. The orientation of the clusters magnetic moments occurs in an external magnetic field.

Keywords

dispersed medium, spin paramagnetism, magnetic susceptibility, magnetization

References

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