About this Abstract |
Meeting |
2023 TMS Annual Meeting & Exhibition
|
Symposium
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Neutron and X-ray Scattering in Materials Science
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Presentation Title |
L-59: Thermodynamics of Elinvar Behavior: An Experimental Study with Nuclear X-ray Scattering |
Author(s) |
Pedro Guzman, Stefan Lohaus, Camille Bernal-Choban, Brent Fultz |
On-Site Speaker (Planned) |
Pedro Guzman |
Abstract Scope |
Fe-45%Ni exhibits a temperature-independent bulk modulus over a wide temperature range at ambient pressure; this anomaly is known as the “Elinvar effect”. We performed X-ray diffractometry experiments at several conditions of pressure and temperature to measure the bulk modulus (B = -V dp/dV) of Fe-45%Ni, confirming it has a negligible temperature dependence at low pressures. Next, we performed nuclear resonant inelastic X-ray scattering and nuclear forward scattering experiments at room temperature and several conditions of pressure to probe the phonon spectrum and magnetism of Fe-45%Ni. These measurements allow us to quantify the vibrational and magnetic entropies and investigate the effects of vibrational and magnetic degrees of freedom on the bulk modulus. At pressures of Elinvar behavior, we report a cancellation of phonon and magnetic entropies that results in the weak temperature dependence of the bulk modulus. This work was supported by the National Science Foundation under Grant No. 1904714. |
Proceedings Inclusion? |
Planned: |
Keywords |
Magnetic Materials, Other, Other |