希少・有害元素代替のための3d多元系機能材料の開発研究

Abstract

Research and development of 3d multinary alloys and compounds for functional materials in terms of substitution of materials containing rare and toxic elements have been carried out extensively. Fe2VAl Heusler alloy and its related alloys exhibit a large Seebeck coefficient, therefore, these alloys have a potential as a substitute of the Bi-Te system for room-temperature thermoelectric materials. Furthermore, Pb-Zn-Te electrostrictive and TbFe2-based magnetostrictive materials are probably replaced with Ni-based magnetic shape memory Heusler alloys, which exhibit a large magnetic-field induced strain. In addition, the control of a large negative thermal expansion of Mn3XN (X=Zn, Ga)anti-Perovskite compounds by partial substitution is useful way to overcome a usage of expensive W element and its compounds. Finally, we focus on magnetic refrigerants which are keenly desired in utilization of magnetic refrigeration. The existing candidates for magnetic refrigerants are limited to compounds containing elements such as As, Gd and Sb. On the other hand, La(FexSi1-x)13 compounds offer advantages on account of environmental safety, low-prices, and a large magnetocaloric effects. To utilize these 3d-based functional materials by taking advantage of the ability to control the electronic state in multinary system, the material designs based on electronic structures and supports of computer-aided phase diagrams are highly useful.