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

• Published in: High pressure research 2018-07, Vol.38 (3), p.270-280
• Main Authors: Perreault, Christopher S., Velisavljevic, Nenad, Samudrala, Gopi K., Kalai Selvan, G., Vohra, Yogesh K.
• Format: Article
• Language: English
• Subjects: Alloys; Cerium; cerium-praseodymium; Collapse; diamond anvil cell; Diamond anvil cells; Diamonds; electrical TRANSPORT; equation of state; high pressure; MATERIALS SCIENCE; phase transformations; Phase transitions; Praseodymium; Praseodymium base alloys; Rare earth alloys; rare earth metals and alloys; Uranium; volume collapse; X-ray diffraction
• ISSN: 0895-7959; 1477-2299
• DOI: 10.1080/08957959.2018.1484917

Cerium-12at%Praseodymium(Ce 0.88 Pr 0.12 ) and Ce-50at%Praseodymium(Ce 0.50 Pr 0.50 ) alloy samples that contain a random solid-solution of Ce (4f 1 (J = 5/2)) and Pr (4f 2 (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 0.88 Pr 0.12 alloy crystallizes in a face-centered cubic (γ-phase) structure at ambient conditions, while Ce 0.50 Pr 0.50 alloy crystallizes in the double hexagonal close packed (dhcp) structure at ambient conditions. Two distinct volume collapse transitions are observed in Ce 0.88 Pr 0.12 alloy at 1.5 GPa and 18 GPa with volume change of 8.5% and 3% respectively. In contrast, Ce 0.50 Pr 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.