Long-range ordering of reduced magnetic moments in the spin-gap compound CeOs{sub 2}Al{sub 10} as seen via muon spin relaxation and neutron scattering

Journal Article · Wed Sep 01 00:00:00 EDT 2010 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.82.104405· OSTI ID:21421413

Adroja, D T; Hillier, A D; Kockelmann, W A; Anand, V K; Stewart, J R; Taylor, J ^[1]; Deen, P P ^[2]; Strydom, A M ^[3]; Muro, Y; Kajino, J; Takabatake, T ^[4]

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1. ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot Oxon OX11 0QX (United Kingdom)
2. Institute Laue-Langevin, BP 156, 6 Rue Jules Horowitz, 38042 Grenoble Cedex (France)
3. Physics Department, University of Johannesburg, P.O. Box 524, Auckland Park 2006 (South Africa)
4. Department of Quantum Matter, ADSM, and IAMR, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan)

We have carried out neutron diffraction, muon spin relaxation ({mu}SR), and inelastic neutron scattering (INS) investigations on a polycrystalline sample of CeOs{sub 2}Al{sub 10} to investigate the nature of the phase transition observed near 29 K in the resistivity and heat capacity. Our {mu}SR data clearly reveal coherent frequency oscillations below 28 K, indicating the presence of an internal field at the muon site, which confirms the long-range magnetic ordering of the Ce moment below 28 K. Upon cooling the sample below 15 K, unusual behavior of the temperature-dependent {mu}SR frequencies may indicate either a change in the muon site, consistent with the observation of superstructure reflections in electron diffraction, or a change in the ordered magnetic structure. Neutron diffraction data do not reveal any clear sign of either magnetic Bragg peaks or superlattice reflections. Furthermore, INS measurements clearly reveal the presence of a sharp inelastic excitation near 11 meV between 5 and 26 K, due to opening of a gap in the spin-excitation spectrum, which transforms into a broad response at and above 30 K. The magnitude of the spin gap (11 meV) as derived from the INS peak position agrees very well with the gap value as estimated from the bulk properties.

• OSTI ID: 21421413
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 82, Issue 10; Other Information: DOI: 10.1103/PhysRevB.82.104405; (c) 2010 The American Physical Society; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM COMPOUNDS
BRAGG CURVE
CERIUM COMPOUNDS
ELECTRON DIFFRACTION
EXCITATION
INELASTIC SCATTERING
MAGNETIC MOMENTS
MAGNETIZATION
MUON SPIN RELAXATION
NEUTRON DIFFRACTION
OSCILLATIONS
OSMIUM COMPOUNDS
PHASE TRANSFORMATIONS
POLYCRYSTALS
REFLECTION
SPECIFIC HEAT
SPECTRA
SUPERLATTICES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0013-0065 K
COHERENT SCATTERING
CRYSTALS
DIAGRAMS
DIFFRACTION
ENERGY-LEVEL TRANSITIONS
INFORMATION
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
REFRACTORY METAL COMPOUNDS
RELAXATION
SCATTERING
TEMPERATURE RANGE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS