Volume and structural study of Fe64Mn36 anti-ferromagnetic Invar alloy under high pressure |
| |
Authors: | M Matsushita S NakanoH Ohfuji I YamadaT Kikegawa |
| |
Institution: | a Department of Mechanical Engineering, Graduate School of Science and Engineering, Ehime University, 3-Bunkyocho, Matsuyama 790-0826, Japan b National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan c Geodynamics Research Center, Ehime University, 2-Bunkyocho, Matsuyama 790-0826, Japan d Department of Chemistry and Biology, Graduate School of Science and Engineering, Ehime University, 2-Bunkyocho, Matsuyama 790-0826, Japan e High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan |
| |
Abstract: | We have investigated the pressure variation of the volume and structure of an FCC Fe64Mn36 anti-ferromagnetic Invar alloy. The inclination of the pressure-volume (P-V) curve of the FCC structure becomes discontinuous at a pressure of 4 GPa. According to the bulk modulus at zero pressure estimated by the Birch-Murnaghan equation of state, the pressure between 4 and 10 GPa is 33 GPa larger than that at a pressure below 4 GPa. Considering previous experiments on magnetism at high pressure the Neel temperature at 4 GPa almost decreases to room temperature. These results suggest that the increase in the bulk modulus by 33 GPa can be attributed to the pressure-induced magnetic phase transition from anti-ferromagnetism to paramagnetism. Volume at zero pressure was estimated using the Birch-Murnaghan equation of state. The volume of FCC structure in the anti-ferromagnetic state was 1.17% larger than the volume in the paramagnetic state, namely, the spontaneous magnetostriction was 1.17%. Pressure-induced structural transition from FCC to HCP occurs with an increase in the pressure, especially at up to 5 GPa. The value of c/a is 1.62; this value almost corresponds to that of an ideal HCP structure. The bulk modulus of the HCP structure estimated by the Birch-Murnaghan equation of state is larger than that of the FCC structure, and the volume/atom ratio is smaller than that of the FCC structure. |
| |
Keywords: | Magneto-volume effect High pressure X-ray diffraction Itinerant magnetism Invar effect Anti-ferromagnetism |
本文献已被 ScienceDirect 等数据库收录! |
|