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Author Sechovsky, V. ♦ Prokes, K. ♦ Svoboda, P. ♦ Syshchenko, O. ♦ Chernyavski, O. ♦ Sato, H. ♦ Fujita, T. ♦ Suzuki, T. ♦ Doerr, M. ♦ Rotter, M.
Sponsorship (US)
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Publisher The American Physical Society
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ CRITICAL FIELD ♦ MAGNETIC FIELDS ♦ MONOCRYSTALS ♦ NEUTRON DIFFRACTION ♦ SPECIFIC HEAT
Abstract We report on low-temperature measurements of magnetization, magnetoresistivity, Hall resistivity, magnetostriction, and elastic moduli on a UNiAl single crystal in magnetic fields up to 14 T applied along the c axis of the hexagonal structure. UNiAl is an itinerant 5f-electron antiferromagnet below T{sub N}=19.3K. At temperatures below 7 K ({similar_to}0.3T{sub N}), it exhibits a first-order metamagnetic transition (MT) at a critical field {mu}{sub 0}H{sub c}{approximately}11.35T between the low-field antiferromagnetic state and the high-field ferromagnetic one. The transition is accompanied by a sharp anomaly in transport and lattice properties. A striking observation is that the {open_quotes}virgin{close_quotes} curves expressing the field dependence of the various electronic properties clearly differ from those observed on a sample that has once appeared in the high-field state. This irreversibility in bulk properties corresponds to an irreversible change of the magnetic-structure propagation vector within the basal plane observed by neutron diffraction. The different shapes of M(H), {rho}(H), and {rho}{sub H}(H) curves are strongly suggestive of field-induced changes in the spectrum of spin fluctuations, which play a substantial role in the physics of UNiAl. This seems to be corroborated by the effect of {open_quotes}high-field annealing{close_quotes} on the low-temperature specific-heat data. The irreversibility vanishes at temperatures T{ge}7K where the MT loses its first-order character. {copyright} 2001 American Institute of Physics.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2001-06-01
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 89
Issue Number 11


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