Abstract
Absorption of ultrasound in nanocomposite materials during the application of external magnetic field was considered in this study. Interaction of acoustic waves with crystal lattices of condensed media depends on many factors such as the type of the crystal lattice, Debye temperature and temperature of the condensed medium, as well as Debye frequency and frequency of the ultrasound. Debye frequency and Debye temperature determine elasticity of the crystal lattice and, consequently, its sound absorbing properties. For measurement and calculation of the coefficient of ultrasound absorption it is necessary to estimate the interaction of acoustic phonons with thermal phonons and electrons of investigated crystalline material. Application of external magnetic field on given material leads to the appearance of magnons that interact with the crystal lattice. As a result the ratio "acoustic phonon-thermal phonon" and, accordingly, sound absorption quantitatively increase. Experimental results obtained in this study coincide with the general picture of sound absorption obtained by other researchers, for example, in the measurement of acoustomagnetic resonance and in concept of magnon-phonon interaction.