%A Yaocen Wang(汪姚岑), Ziyan Hao(郝梓焱), Yan Zhang(张岩), Xiaoyu Liang(梁晓宇), Xiaojun Bai(白晓军), and Chongde Cao(曹崇德)
%T Formation of L10-FeNi hard magnetic material from FeNi-based amorphous alloys
%0 Journal Article
%D 2022
%J Chin. Phys. B
%R 10.1088/1674-1056/ac280a
%P 46301-046301
%V 31
%N 4
%U {https://cpb.iphy.ac.cn/CN/abstract/article_124510.shtml}
%8 2022-03-16
%X L10-FeNi hard magnetic alloy with coercivity reaching 861 Oe was synthesized through annealing Fe42Ni41.3Si8B4P4Cu0.7 amorphous alloy, and the L10-FeNi formation mechanism has been studied. It is found the L10-FeNi in annealed samples at 400 ℃ mainly originated from the residual amorphous phase during the second stage of crystallization which could take place over 60 ℃ lower than the measured onset temperature of the second stage with a 5 ℃/min heating rate. Annealing at 400 ℃ after fully crystallization still caused a slight increase of coercivity, which was probably contributed by the limited transformation from other high temperature crystalline phases towards L10 phase, or the removal of B from L10 lattice and improvement of the ordering quality of L10 phase due to the reduced temperature from 520 ℃ to 400 ℃. The first stage of crystallization has hardly direct contribution to L10-FeNi formation. Ab initio simulations show that the addition of Si or Co in L10-FeNi has the effect of enhancing the thermal stability of L10 phase without seriously deteriorating its magnetic hardness. The non-monotonic feature of direction dependent coercivity in ribbon segments resulted from the combination of domain wall pinning and demagnetization effects. The approaches of synthesizing L10-FeNi magnets by adding Si or Co and decreasing the onset crystallization temperature have been discussed in detail.