An inelastic neutron scattering study of single-crystal heavy-fermion YbAgGe
2005; IOP Publishing; Volume: 17; Issue: 2 Linguagem: Inglês
10.1088/0953-8984/17/2/006
ISSN1361-648X
AutoresB. Fåk, D. F. McMorrow, P. G. Niklowitz, S. Raymond, E. Ressouche, J. Flouquet, P. C. Canfield, Sergey L. Bud’ko, Y. Janssen, M. Gutmann,
Tópico(s)Physics of Superconductivity and Magnetism
ResumoSingle crystals of the heavy-fermion compound YbAgGe have been studied by neutron scattering. The magnetic ordering occurring below K is characterized by a commensurate propagation vector k = (1/3,0,1/3) and the moments in the basal plane of the hexagonal structure. The dynamic magnetic susceptibility is dominated by quasielastic spin fluctuations with a characteristic energy Γq(T) of the order of 1 meV. The spins fluctuate predominantly in the basal plane. No spin-wave excitations are observed in the magnetically ordered phase. Below the Kondo temperature, K, Γq(T) shows a strong q-dependence for wavevectors along the direction, but is q-independent in the basal plane. Γq(T) initially shows a rapid increase with temperature T at the antiferromagnetic zone centre, but follows a standard law for other q values and for T>TK in general. These observations classify YbAgGe as a well-behaved heavy-fermion compound with a particular q-dependence of the antiferromagnetic spin fluctuations, possibly related to the geometrical frustration of the Y b3+ ions.
Referência(s)