Details

Autor(en) / Beteiligte

• Ishimatsu, N
• Iwasaki, S
• Kousa, M
• Kato, S
• Nakajima, N
• Kitamura, N
• Kawamura, N
• Mizumaki, M
• Kakizawa, S
• Nomura, R
• Irifune, T
• Sumiya, H

Titel

Elongation of Fe-Fe atomic pairs in the Invar alloy Fe65Ni35

Ist Teil von

• Physical review. B, 2021-06, Vol.103 (22), p.1

Ort / Verlag

College Park: American Physical Society

Erscheinungsjahr

2021

Link zum Volltext

Quelle

American Physical Society Journals

Beschreibungen/Notizen

• In this study, atomic-scale origin of the Invar effect, which is nearly-zero thermal expansion observed in the Invar alloy Fe65Ni35, 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 were ∼0.02 Å 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 at Pc ≈ 7 GPa. 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.