Pressure induced Invar effect in Fe55Ni45: An experimental study with nuclear resonant scattering
Journal Article
·
· Physical Review. B
- California Institute of Technology (CalTech), Pasadena, CA (United States)
- Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Univ. of Chicago, IL (United States); Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Pressure-dependent synchrotron x-ray diffraction (XRD), nuclear resonant inelastic x-ray scattering (NRIXS), and nuclear forward scattering (NFS) measurements were made on 57Fe55Ni45. XRD measurements were at 298 and 392 K at pressures up to 20 GPa, confirming a pressure-induced Invar effect between 7 and 13 GPa. A decrease of the 57Fe magnetic moment was found in NFS measurements under pressure, showing an increase in magnetic entropy. The 57Fe phonon density of states (DOS) was obtained from NRIXS measurements. The low thermal expansion in the high-pressure Invar region originates from a competition between the thermal expansion from spins and phonons as calculated from Maxwell relations. Finally, the longitudinal phonon modes changed their pressure dependence near the Curie transition, which is evidence for a spin-phonon interaction.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); USDOE National Nuclear Security Administration (NNSA); National Science Foundation (NSF)
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 2499472
- Alternate ID(s):
- OSTI ID: 2474055
- Journal Information:
- Physical Review. B, Journal Name: Physical Review. B Journal Issue: 14 Vol. 110; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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