Magnetic excitations in the heavy-fermion superconductor URu sub 2 Si sub 2

Journal Article · Sat Jun 01 00:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.12809· OSTI ID:5686096

Broholm, C ^[1]; Lin, H ^[2]; Matthews, P T ^[3]; Mason, T E ^[4]; Buyers, W J.L. ^[5]; Collins, M F ^[4]; Menovsky, A A ^[6]; Mydosh, J A ^[7]

---

1. Riso National Laboratory, DK-4000 Roskilde, Denmark (DK) AT T Bell Laboratories, Murray Hill, New Jersey 07974 (USA)
2. Atomic Energy of Canada Ltd., Chalk River Laboratories, Chalk River, Ontario, K0J 1J0, Canada (CA) Department of Physics, McMaster University, Hamilton, Ontario, L8S 4M1, Canada (CA)
3. Department of Physics, Queen's University, Kingston, Ontario, K7L 3N6, Canada (CA)
4. Department of Physics, McMaster University, Hamilton, Ontario, L8S 4M1, Canada (CA)
5. Atomic Energy of Canada Ltd., Chalk River Laboratories, Chalk River, Ontario, K0J 1J0, Canada (CA)
6. Natuurkundig Laboratorium Der Universiteit van Amsterdam, NL-1018XE Amsterdam, The Netherlands (NL) Kammerlingh Onnes Laboratorium, Rijksuniversiteit te Leiden, NL-2300RA Leiden, The Netherlands (NL)
7. Kammerlingh Onnes

Antiferromagnetic order and fluctuations in the heavy-fermion superconductor URu{sub 2}Si{sub 2} have been studied by magnetic neutron scattering. Below {ital T}{sub {ital N}}=17.5 K, URu{sub 2}Si{sub 2} is a type-I antiferromagnet with an anomalously small ordered moment of (0.04{plus minus}0.01){mu}{sub {ital B}} polarized along the tetragonal {ital c} axis. Dispersive resonant excitations exist in the ordered state with a zone-center gap of 0.43 THz. The excitations are polarized along the ordered moment and have a large dipolar matrix element, which suggests that they are coupled transitions between singlet crystal-field-like states. For energy transfer above 3 THz, peaks have not been identified in the magnetic excitation spectra, but instead a continuous spectrum of scattering peaked around the ordering wave vector indicates the presence of overdamped antiferromagnetically correlated spin fluctuations. Upon heating above {ital T}{sub {ital N}}, the resonant excitations abruptly become heavily damped but the magnetic scattering at higher energies does not change at {ital T}{sub {ital N}}. Instead, the disappearance of the antiferromagnetic modulation of the higher-energy scattering coincides with the maximum in the resistivity of URu{sub 2}Si{sub 2}.

• OSTI ID: 5686096
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 43:16; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ACTINIDE COMPOUNDS
ANTIFERROMAGNETISM
COHERENT SCATTERING
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FLUCTUATIONS
MAGNETISM
NEUTRON DIFFRACTION
PHYSICAL PROPERTIES
REFRACTORY METAL COMPOUNDS
RUTHENIUM COMPOUNDS
RUTHENIUM SILICIDES
SCATTERING
SILICIDES
SILICON COMPOUNDS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
URANIUM COMPOUNDS
VARIATIONS