Affiliations: [a] Department of Radiophysics, Taras Shevchenko
University, Glushkov str. 2, build. 5, 03127, Kiev-127, Ukraine | [b] Institute for Metal Physics, Ukrainian Academy of
Sciences, Vernadskii str. 36, 03142, Kiev-142, Ukraine | [c] Helsinki University of Technology, Laboratory of
Materials Science, P.O. Box 6200, Espoo FI-02015 TKK, Finland
Correspondence:
[*]
Corresponding author: Victor A. L'vov, Department of
Radiophysics, Taras Shevchenko University, Glushkov str.~2, build. 5, 03127,
Kiev-127, Ukraine. Tel.: +38 044 452 01 34 (home); +38 044 526 05 43 (Dept. of
Radiophysics); E-mail: victorlvov@univ.kiev.ua
Abstract: The isothermal time-dependent deformation of the ferromagnetic
Ni-Mn-Ga martensite in the steady magnetic field has been studied both
experimentally and theoretically. The role of long wavelength thermal phonons
in the deformation process has been disclosed by means of evaluation of the
fluctuating mechanical stress, which these phonons induce inside the
experimentally observed elements of martensitic structure. A simple
relationship between the magnitude of effective fluctuating stress,
temperature-dependent elastic modulus and twin width has been derived. In this
way, a strong interdependence between the twin width and the effect of thermal
phonons on the twin structure is predicted. The fluctuation mechanism of
reversibility of the magnetically induced deformation has been deduced from the
experimental and theoretical results.
Keywords: Ferromagnetic martensite, magnetic aftereffects, structure, thermal phonons
