2 Institute for Materials Research, Tohoku University
Date & Time: 15:00 - 16:00, Oct. 10th (Tue), 2023.
Place: 2nd Conference Room, 1F, Main Bldg., Sengen site.
Landau-type theory for description of MCE for the solids exhibiting magnetic and magnetostructural phase transitions
2 Institute for Materials Research, Tohoku University
Abstract:
Materials exhibiting different types of magnetic and magnetostructural phase transitions are promising candidates for ferroic cooling. A proper coupling between magnetic and structural degrees of freedom is critical for the emergence and control of magnetocaloric effects (MCE) in solids. Landau theory is an effective and well approved tool for the description of physical phenomena accompanying different phase transitions. The special version of Landau-type theory was developed for the quantitative description of physical effects accompanying the magnetostructural phase transitions in multiferroic materials [1-4]. Theory starts from the analysis of Gibbs potential, as so the theory includes magnetic and elastic subsystems and its interrelation. In particular, this approach allows to describe:
1) disappearance of temperature and stress hysteresis in post-critical regime of deformation during structural martensitic transformation of shape memory alloy [1,2]. The theory showed that alloys with low values of shear elastic modules are promising candidates for observation of large anhysteretic deformations.
2) inverse magnetocaloric effect in the Fe-Rh alloy, which undergoes the isostructural ferromagnetic-antiferromagnetic phase transition [3]. It is argued that antiferromagnetic solids with weak exchange interaction between the magnetic sublattices can show the noticeable MCE under the moderate magnetic field.
3) conventional and inverse magnetocaloric effects in metamagnetic Ni-Mn-Sn Heusler alloys [4,5]. It has been shown that the contributions of the elastic and magnetic subsystems to the total entropy change are close in magnitude in the temperature range of magnetostructural phase transition.
The Landau-type phenomenological approach serves as a bridge between macroscopic observations and microscopic models, offering a framework to describe complex phenomena. By facilitating the theoretical comprehension of phase transitions, this approach plays an important role in the design and development of novel materials with target properties.
References:
[1] A. Kosogor, V.A. L’vov, V.A. Chernenko, E. Villa, J.M. Barandiaran, T. Fukuda, T. Terai, T. Kakeshita, Acta Mat. 66, 79 (2014).
[2] A. Kosogor, J. Appl. Phys. 119, 224903 (2016).
[3] V.A. L'vov, A. Kosogor, J. Magn. Magn. Mater. 517, 167269 (2021).
[4] V.A. L'vov, A. Kosogor, J.M. Barandiaran, V.A. Chernenko, J. Appl. Phys. 119, 013902 (2016).
[5] A. Kosogor, J.M. Barandiaran, V.A. L'vov, J.R. Fernandez, V.A. Chernenko, J. Appl. Phys. 121, 183901 (2017).
1) disappearance of temperature and stress hysteresis in post-critical regime of deformation during structural martensitic transformation of shape memory alloy [1,2]. The theory showed that alloys with low values of shear elastic modules are promising candidates for observation of large anhysteretic deformations.
2) inverse magnetocaloric effect in the Fe-Rh alloy, which undergoes the isostructural ferromagnetic-antiferromagnetic phase transition [3]. It is argued that antiferromagnetic solids with weak exchange interaction between the magnetic sublattices can show the noticeable MCE under the moderate magnetic field.
3) conventional and inverse magnetocaloric effects in metamagnetic Ni-Mn-Sn Heusler alloys [4,5]. It has been shown that the contributions of the elastic and magnetic subsystems to the total entropy change are close in magnitude in the temperature range of magnetostructural phase transition.
The Landau-type phenomenological approach serves as a bridge between macroscopic observations and microscopic models, offering a framework to describe complex phenomena. By facilitating the theoretical comprehension of phase transitions, this approach plays an important role in the design and development of novel materials with target properties.
References:
[1] A. Kosogor, V.A. L’vov, V.A. Chernenko, E. Villa, J.M. Barandiaran, T. Fukuda, T. Terai, T. Kakeshita, Acta Mat. 66, 79 (2014).
[2] A. Kosogor, J. Appl. Phys. 119, 224903 (2016).
[3] V.A. L'vov, A. Kosogor, J. Magn. Magn. Mater. 517, 167269 (2021).
[4] V.A. L'vov, A. Kosogor, J.M. Barandiaran, V.A. Chernenko, J. Appl. Phys. 119, 013902 (2016).
[5] A. Kosogor, J.M. Barandiaran, V.A. L'vov, J.R. Fernandez, V.A. Chernenko, J. Appl. Phys. 121, 183901 (2017).
(Contact)
H. Sepehri-Amin, Green Magnetic Materials Gr..
E-mail: H.SEPEHRIAMIN[at]nims.go.jp
E-mail: H.SEPEHRIAMIN[at]nims.go.jp