Elongation of Fe-Fe atomic pairs in the Invar alloy Fe65Ni35
Elongation of Fe-Fe atomic pairs in the Invar alloy Fe65Ni35
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Invar合金Fe65Ni35中Fe-Fe原子对的伸长率
DOI：
10.1103/physrevb.103.l220102
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发表时间：
2021
影响因子：
3.7
通讯作者：
H.
中科院分区：
文献类型：
--
作者：
Ishimatsu;N.;Iwasaki;S.;Kousa;M.;Kato;S.;Nakajima;N.;Kitamura;N.;Kawamura;N.;Mizumaki;M.;Kakizawa;S.;Nomura;R.;Irifune;T. and Sumiya;H.
本研究利用扩展X射线吸收精细结构和X射线衍射的互补数据集，用逆蒙特卡罗分析方法研究了因瓦合金中观察到的近零热膨胀的因瓦效应的原子尺度起源。在本研究的最低气压下，最近邻的Fe-Fe原子对的原子间距比Fe-Ni和Ni-Ni原子对的原子间距都要大。随着压力的增加，Fe-Fe对的伸长率受到抑制，当压力高于从铁磁相向顺磁相转变的压力时，三对的伸长率相当。因此，由于磁体效应，Fe-Fe对的体积膨胀起主要作用。由于在非因瓦铁镍合金的Fe-Fe对中观察到了类似的伸长量，我们推断因瓦效应源于Fe-Fe对的数量与它们的延伸率之间的微妙平衡与磁化强度的关系。
In this study, atomic-scale origin of the Invar effect, which is nearly-zero thermal expansion observed in the Invar alloy, was investigated by reverse Monte Carlo analysis using complementary data sets of extended x-ray absorption fine structure and x-ray diffraction. The interatomic distances of the nearest neighboring Fe-Fe atomic pairs wereÅ longer than those of the Fe-Ni and Ni-Ni pairs at the minimum pressure in this study (0.6 GPa). The elongation in the Fe-Fe pairs was suppressed with increasing pressure, and the distances of the three pairs were comparable under pressures above the magnetic transition from ferromagnetic to paramagnetic phase atGPa. Therefore, the Fe-Fe pairs dominantly contribute to the volume expansion due to the magnetovolume effect. Because a similar magnitude of elongation was observed in the Fe-Fe pairs of a non-Invar Fe-Ni alloy, we conclude that the Invar effect originates from the delicate balance between the number of Fe-Fe pairs and their elongation depending on the magnetization.