Registration Number
0220U104518,
0117U000433
, R & D reports
Title
Thermodynamic and magnetic-resonance properties of functional materials with magnetic-structural phase transformations.
popup.stage_title
Head
Bariakhtar Viktor H., Доктор фізико-математичних наук
Registration Date
21-12-2020
Organization
Institute of Magnetism NAS of Ukraine and MES of Ukraine
popup.description2
The general method for constructing a model of the dissipative function has been developed, which describes the relaxation processes caused by the damping of bound magnetoacoustic waves in magnetically ordered materials. The obtained model of the dissipative function is based on the symmetry of the magnet and describes both exchange and relativistic interactions in the crystal. The model takes into account the contributions to the dissipation of both the magnetic and elastic subsystems, and the relaxation associated with the magnetoelastic interaction. The dispersion law of coupled magnetoelastic waves for an uniaxial ferromagnet of the "light axis" type is calculated. It is shown that the contribution of magnetoelastic interaction to dissipative processes can play a significant role in the case of magnetoacoustic resonance.
The theory of direct and inverse giant magnetocaloric effect has been developed. A giant magnetocaloric effect has been considered in an alloy with shape memory effect, in which the phase transition of the first type from the cubic ferromagnetic phase to the tetragonal antiferromagnetic phase takes place. The agreement between the theoretical results and the available experimental data is demonstrated. It is shown that alloys in which there is a phase transition to the antiferromagnetic phase with a weak exchange interaction between magnetic sublattices are promising for applications in magnetic cooling technology.
Product Description
popup.authors
Gorobets Yuriy І.
Danilevich Oleksandr G.
Kosogor Anna O.
L'vov Viktor A.
popup.nrat_date
2020-12-21
