Thermal expansion of Ce sub 3 Bi sub 4 Pt sub 3 at ambient and high pressures

Journal Article · Thu Oct 01 00:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.46.8067· OSTI ID:7229313

Kwei, G H ^[1]; Lawrence, J M ^[2]; Canfield, P C; Beyermann, W P; Thompson, J D; Fisk, Z; Lawson, A C; Goldstone, J A ^[1]

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1. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States) Physics Department, University of California at Irvine, Irvine, California 92717 (United States)

Ce{sub 3}Bi{sub 4}Pt{sub 3} is a cerium compound that exhibits a hybridization gap and concomitant semiconducting behavior in the coherent ground state. Using neutron powder diffraction, we have determined the variation of the lattice constant with temperature at two pressures ({ital P}=10{sup {minus}3} and 17.7 kbar), and determined the bulk modulus and atomic mean-square displacements for Ce{sub 3}Bi{sub 4}Pt{sub 3} and its normal analog, La{sub 3}Bi{sub 4}Pt{sub 3}. The thermal expansion {Delta}{beta} in Ce{sub 3}Bi{sub 4}Pt{sub 3} exhibits a maximum at {ital T}{sub max}=50 K at ambient pressure. Below 50 K, the bulk modulus {Delta}{ital B} is proportional to {ital T}{Delta}{beta}. We apply a Grueneisen analysis, under the assumption that the free energy exhibits {ital T}/{ital T}{sub 0}({ital V}) scaling. The Grueneisen parameter deduced from the ratio {Delta}{ital B}/{ital T}{Delta}{beta} is consistent with the value {Omega}=36 deduced from the pressure variation of {ital T}{sub max}. The analysis allows us to predict the temperature dependence of the 4{ital f} specific heat ({Delta}{ital C}{proportional to}{Delta}{beta}/{Omega}), which thus has a maximum at 50 K and a high-temperature entropy nearly equal the expected value {ital R} ln6. We argue that the maximum at 50 K reflects an (indirect) hybridization gap of order 100 K. We show further that the lattice constant anomaly {Delta}{ital a}{sub 0} is proportional to the effective moment {ital T}{chi}; this suggests that a relationship known to be valid for antiferromagnets, namely {partial derivative}({ital T}{chi})/{partial derivative}{ital T}{proportional to}{Delta}{ital C} where {Delta}{ital C} is the specific heat, may be valid for Ce{sub 3}Bi{sub 4}Pt{sub 3}.

• OSTI ID: 7229313
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 46:13; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BISMUTH COMPOUNDS
THERMAL EXPANSION
CERIUM COMPOUNDS
PLATINUM COMPOUNDS
GRUENEISEN FORMULA
LATTICE PARAMETERS
NEUTRON DIFFRACTION
POWDERS
PRESSURE DEPENDENCE
COHERENT SCATTERING
DIFFRACTION
EXPANSION
RARE EARTH COMPOUNDS
SCATTERING
TRANSITION ELEMENT COMPOUNDS
360104* - Metals & Alloys- Physical Properties