School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Key Laboratory of Novel Materials for Information Technology of Zhejiang Province, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027, China.
Ferroic Physics Group, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, Japan.
Nat Commun. 2017 Jan 18;8:13937. doi: 10.1038/ncomms13937.
All ferromagnetic materials show deterioration of magnetism-related properties such as magnetization and magnetostriction with increasing temperature, as the result of gradual loss of magnetic order with approaching Curie temperature T. However, technologically, it is highly desired to find a magnetic material that can resist such magnetism deterioration and maintain stable magnetism up to its T, but this seems against the conventional wisdom about ferromagnetism. Here we show that a Fe-Ga alloy exhibits highly thermal-stable magnetization up to the vicinity of its T, 880 K. Also, the magnetostriction shows nearly no deterioration over a very wide temperature range. Such unusual behaviour stems from dual-magnetic-phase nature of this alloy, in which a gradual structural-magnetic transformation occurs between two magnetic phases so that the magnetism deterioration is compensated by the growth of the ferromagnetic phase with larger magnetization. Our finding may help to develop highly thermal-stable ferromagnetic and magnetostrictive materials.
所有铁磁材料的磁化和磁致伸缩等与磁性相关的性能都会随着温度的升高而恶化，这是由于随着接近居里温度 T，磁有序逐渐丧失的结果。然而，从技术角度来看，人们非常希望找到一种能够抵抗这种磁性劣化并在其 T 温度以上保持稳定磁性的磁性材料，但这似乎与铁磁性的传统观念相悖。在这里，我们展示了一种 Fe-Ga 合金在接近其 T（880 K）的温度下表现出非常高的热稳定性磁化。此外，在非常宽的温度范围内，磁致伸缩几乎没有恶化。这种异常行为源于该合金的双磁相性质，其中在两个磁相之间发生逐渐的结构-磁性转变，从而通过具有更大磁化强度的铁磁相的生长来补偿磁性能的劣化。我们的发现可能有助于开发具有高热稳定性的铁磁性和磁致伸缩材料。
