Specific-heat critical behavior of the structural random-field system Dy(As{sub {ital x}}V{sub 1-{ital x}})O{sub 4}

Journal Article · Mon Jan 01 04:00:00 EST 1996 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.53.97· OSTI ID:256717

Slanic, Z; Belanger, D P; Wang, J ^[1]; Taylor, D R ^[2]

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1. Physics Department, University of California Santa Cruz, Santa Cruz, California 95064 (United States)
2. Department of Physics, Queen`s University, Kingston (Canada) K7L3N6

The specific-heat critical behaviors of the pure Ising transition in DyVO{sub 4} and the random-field Ising transition in Dy(As{sub {ital x}}V{sub 1-{ital x}})O{sub 4} have been measured. The critical exponent {alpha} and amplitude ratio {ital A}{sup +}/{ital A}{sup -} for DyVO{sub 4}, which has {ital T}{sub {ital c}}=14.82 K, are in excellent agreement with the known pure {ital d}=3 Ising exponents. The random fields generated by the local strain fields in Dy(As{sub {ital x}}V{sub 1-{ital x}})O{sub 4} depress the transitions to {ital T}{sub {ital c}}=13.45 K and {ital T}{sub {ital c}}=7.7 K for {ital x}=0.05 and {ital x}=0.15, respectively. With increasing {ital x}, the transition becomes rounded and severely depressed in size. The value of {alpha} appears large and negative for {ital x}=0.15. As the random-field strength increases, i.e., the value of {ital x} gets larger, the amount of entropy change associated with the transition rapidly decreases. Where the missing entropy reappears is not adequately understood. {copyright} {ital 1996 The American Physical Society.}

• DOE Contract Number: FG03-87ER45324
• OSTI ID: 256717
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 1 Vol. 53; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ARSENIC OXIDES
CRITICAL EXPONENTS
DYSPROSIUM OXIDES
ENTROPY
ISING MODEL
RANDOMNESS
SPECIFIC HEAT
STRAINS
VANADIUM OXIDES