Volume collapse phase transitions in cerium-praseodymium alloys under high pressure

ABSTRACT

Cerium-12at%Praseodymium(Ce_0.88Pr_0.12) and Ce-50at%Praseodymium(Ce_0.50Pr_0.50) alloy samples that contain a random solid-solution of Ce (4f¹ (J = 5/2)) and Pr (4f² (J = 4)) localized f-states have been studied by angle dispersive x-ray diffraction in a diamond anvil cell to a pressure of 65 GPa and 150 GPa respectively using a synchrotron source. Ce_0.88Pr_0.12 alloy crystallizes in a face-centered cubic (γ-phase) structure at ambient conditions, while Ce_0.50Pr_0.50 alloy crystallizes in the double hexagonal close packed (dhcp) structure at ambient conditions. Two distinct volume collapse transitions are observed in Ce_0.88Pr_0.12 alloy at 1.5 GPa and 18 GPa with volume change of 8.5% and 3% respectively. In contrast, Ce_0.50Pr_0.50 alloy shows only a single volume collapse of 5.6% at 20 GPa on phase transformation to α-Uranium structure under high pressure. Electrical transport measurements under high pressure show anomalies in electrical resistance at phase transitions for both compositions of this alloy.

KEYWORDS:

• Rare earth alloys
• volume collapse
• X-ray diffraction
• electrical TRANSPORT

Acknowledgements

This material is based upon work supported by the Department of Energy-National Nuclear Security Administration under Award Number DE-NA0002928. Los Alamos National Laboratory (LANL) is operated by LANS, LLC for the DOE-NNSA under Contract No. DE-AC52-06NA25396. NV acknowledge funding support from LANL Science Programs 1 and 2. Portions of this work were performed at HPCAT (Sector 16), Advanced Photon Source (APS), Argonne National Laboratory. HPCAT operations are supported by DOE-NNSA under Award No. DE-NA0001974 and DOE-BES under Award No. DE-FG02-99ER45775, with partial instrumentation funding by NSF. APS is supported by DOE-BES, under Contract No. DE-AC02-06CH11357.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This material is based upon work supported by the Department of Energy-National Nuclear Security Administration under Award Number DE-NA0002928. Los Alamos National Laboratory (LANL) is operated by LANS, LLC for the DOE-NNSA under Contract No. DE-AC52-06NA25396. NV acknowledge funding support from LANL Science Programs 1 and 2. Portions of this work were performed at HPCAT (Sector 16), Advanced Photon Source (APS), Argonne National Laboratory. HPCAT operations are supported by DOE-NNSA under Award No. DE-NA0001974 and DOE-BES under Award No. DE-FG02-99ER45775, with partial instrumentation funding by NSF. APS is supported by DOE-BES, under Contract No. DE-AC02-06CH11357.