Dynamics of iron atoms across the pressure-induced Invar transition in Pd_3Fe
Abstract
The ^(57)Fe phonon partial density of states (PDOS) in L1_2-ordered Pd_3Fe was studied at high pressures by nuclear resonant inelastic x-ray scattering (NRIXS) measurements and density functional theory (DFT) calculations. The NRIXS spectra showed that the stiffening of the ^(57)Fe PDOS with decreasing volume was slower from 12 to 24 GPa owing to the pressure-induced Invar transition in Pd_3Fe, with a change from a high-moment ferromagnetic (FM) state to a low-moment (LM) state observed by nuclear forward scattering. Force constants obtained from fitting to a Born–von Kármán model showed a relative softening of the first-nearest-neighbor (1NN) Fe-Pd longitudinal force constants at the magnetic transition. For the FM low-pressure state, the DFT calculations gave a PDOS and 1NN longitudinal force constants in good agreement with experiment, but discrepancies for the high-pressure LM state suggest the presence of short-range magnetic order.
Additional Information
© 2011 American Physical Society. Received 17 August 2010; revised 24 February 2011; published 20 April 2011. We thank Brandon Keith, Jiao Lin, Chen Li, and Michael McKerns for software development and assistance. We thank Kun Woo Kim for assistance with the low-temperature NFS measurements. We thank Olivier Delaire and Max Kresch for helpful discussions. This work benefitted from the DANSE software developed under NSF Award No. DMR-0520547. This work was supported by the Department of Energy through the Carnegie-DOE Alliance Center, funded by the Department of Energy through the Stewardship Sciences Academic Alliance Program. Portions of this work were performed at HPCAT (Sector 16), Advanced Photon Source (APS), Argonne National Laboratory. HPCAT is supported by CIW, CDAC, UNLV, and LLNL through funding from DOE NNSA, DOE BES, and NSF. Use of the APS was supported by DOE BES under Contract No. DE-AC02-06CH11357.Attached Files
Published - Winterrose2011p15700Phys_Rev_B.pdf
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Additional details
- Eprint ID
- 25296
- Resolver ID
- CaltechAUTHORS:20110912-102708891
- NSF
- DMR-0520547
- Department of Energy (DOE) National Nuclear Security Administration
- Department of Energy (DOE)
- DE-AC02-06CH11357
- Created
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2011-09-12Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field