Heat capacity of single-crystal La sub 2 CuO sub 4 and polycrystalline La sub 2 minus x Sr sub x CuO sub 4 (0 le x le 0. 20) from 110 to 600 K

Journal Article · Tue Jan 01 00:00:00 EST 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.239· OSTI ID:6115813

Sun, K; Cho, J H; Chou, F C; Lee, W C; Miller, L L; Johnston, D C ^[1]; Murakami, T ^[2]

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1. Ames Laboratory U.S. Department of Energy and Department of Physics, Iowa State University, Ames, Iowa 50011 (USA) Hidaka, Y.
2. NTT Ibaraki Electrical Communications Laboratories, Nippon Telegraph Telephone Corporation, 162 Tokai, Ibaraki (Japan)

Heat-capacity {ital C}({ital T}) data on the title materials, as well as on CuO for comparison, were obtained with use of a differential scanning calorimeter to a precision of {congruent}0.1--1%. The measurements were carried out (i) to characterize the thermal anomaly at the tetragonal-orthorhombic transition temperature {ital T}{sub 0} of single-crystal La{sub 2}CuO{sub 4} and polycrystalline La{sub 2{minus}{ital x}}Sr{sub {ital x}}CuO{sub 4} (0{le}{ital x}{le}0.20) and (ii) to search for thermal anomalies at the Neel temperature {ital T}{sub {ital N}} of La{sub 2}CuO{sub 4} ({congruent}300 K). We find a cusp-shaped anomaly with a peak at 523 K ({approx}{ital T}{sub 0}) for a single crystal of La{sub 2}CuO{sub 4} with {ital T}{sub {ital N}}=304 K and find the transition to be second order, consistent with previous neutron- and x-ray-diffraction measurements. {ital T}{sub {ital N}} was determined from measurements of the anisotropic magnetic susceptibility on the same crystal, which are also presented. The {ital C}({ital T}) anomaly at {ital T}{sub 0} is smeared out somewhat in polycrystalline La{sub 2}CuO{sub 4}.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6115813
• Journal Information: Physical Review, B: Condensed Matter; (USA), Vol. 43:1; ISSN 0163-1829
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE
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HIGH TEMPERATURE
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MAGNETIC SUSCEPTIBILITY
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MONOCRYSTALS
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Cermets
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