Date & Time: 9:30 - 11:00, June 16th (Fri), 2023.
Place: 1st Conference Room, 1st floor, Sengen.
Development of energy conversion magnetic materials using interaction between magnetism and heat or elasticity
Abstract:
Magnetism interacts with various properties. In this seminar, our results on the development of energy conversion magnetic materials using the interaction between magnetism and heat or elasticity are provided.
The interaction between magnetism and heat, that is magnetocaloric effects have actively investigated for application to magnetic refrigeration, which can achieve high efficiency without harmful refrigerant gases. We focused on the magnetic field-induced first-order transition from the paramagnetic to the ferromagnetic state, which is called the itinerant-electron metamagnetic transition, and found large magnetocaloric effects in La(FexSi1-x)13 compounds. As the Curie temperature was controlled by hydrogen absorption and partial substitutions of elements, large magnetocaloric effects were successfully obtained in relatively low magnetic fields over a wide temperature range from about 20 K to room temperature. Furthermore, we investigated to overcome various hindrances in achieving practical application. For example, although La(FexSi1-x)13 compounds corrode in aqueous solutions for heat exchange, it was significantly suppressed by reducing dissolved oxygen concentration, and hence large magnetocaloric effects were maintained even after immersion in aqueous solution. Currently, La(FexSi1-x)13-based compounds are used as promising materials for the development of magnetic refrigerators in many countries around the world.
The magnetostriction is well known as the interaction between magnetism and elasticity. The inverse effect of magnetostriction (inverse magnetostrictive effect) has attached much attention for application to the vibration energy harvesting, which can generate electric power from ambient vibration. We focused on Fe-Ga alloys, which have superior magnetostrictive and mechanical properties, and demonstrated that vibration power generation devices using Fe-Ga alloy single crystals exhibit excellent power generation properties due to the large inverse magnetostrictive effect. By magneto-optic Kerr effect microscopy, the characteristic modulation of a magnetic domain structure of the single crystal was observed under applied magnetic fields and stresses.
Consequently, we revealed a mechanism of the large inverse magnetostrictive effect, being is the origin of excellent power generation properties.
The interaction between magnetism and heat, that is magnetocaloric effects have actively investigated for application to magnetic refrigeration, which can achieve high efficiency without harmful refrigerant gases. We focused on the magnetic field-induced first-order transition from the paramagnetic to the ferromagnetic state, which is called the itinerant-electron metamagnetic transition, and found large magnetocaloric effects in La(FexSi1-x)13 compounds. As the Curie temperature was controlled by hydrogen absorption and partial substitutions of elements, large magnetocaloric effects were successfully obtained in relatively low magnetic fields over a wide temperature range from about 20 K to room temperature. Furthermore, we investigated to overcome various hindrances in achieving practical application. For example, although La(FexSi1-x)13 compounds corrode in aqueous solutions for heat exchange, it was significantly suppressed by reducing dissolved oxygen concentration, and hence large magnetocaloric effects were maintained even after immersion in aqueous solution. Currently, La(FexSi1-x)13-based compounds are used as promising materials for the development of magnetic refrigerators in many countries around the world.
The magnetostriction is well known as the interaction between magnetism and elasticity. The inverse effect of magnetostriction (inverse magnetostrictive effect) has attached much attention for application to the vibration energy harvesting, which can generate electric power from ambient vibration. We focused on Fe-Ga alloys, which have superior magnetostrictive and mechanical properties, and demonstrated that vibration power generation devices using Fe-Ga alloy single crystals exhibit excellent power generation properties due to the large inverse magnetostrictive effect. By magneto-optic Kerr effect microscopy, the characteristic modulation of a magnetic domain structure of the single crystal was observed under applied magnetic fields and stresses.
Consequently, we revealed a mechanism of the large inverse magnetostrictive effect, being is the origin of excellent power generation properties.
(Contact)
T. Furubayshi, CMSM Administrative Office
E-mail: furubayashi.takao[at]nims.go.jp
E-mail: furubayashi.takao[at]nims.go.jp