Magnetic properties of YbNi5 from 170Yb Mössbauer and magnetisation measurements
CEA, Centre d'Études de Saclay, DSM/DRECAM/Service de Physique de l'État Condensé, 91191 Gif-sur-Yvette, France
Corresponding author: a firstname.lastname@example.org
Published online: 29 June 2007
From Yb170 Mössbauer measurements on YbNi5, we establish: the Yb3+ ground state Kramers doublet is well isolated and has uniaxial anisotropy, the compound magnetically orders at 0.55 K, the Yb3+ moments are aligned along the hexagonal axis, they have a saturated value of 3.9μB and a thermal variation close to a mean field S = 1/2 law. We obtain the strength of the Yb3+–Yb3+ coupling which we find is considerably smaller than that between the rare earths (R3+) in the other RNi5. From a study of the spin dynamics, we find that dynamic short range order is present just above the ordering temperature and that above 2 K, the relaxation rate of the paramagnetic Yb3+ spins follows a T-linear Korringa law with a relatively pronounced slope which we link to a high density of states at the Fermi level. Magnetic susceptibility and magnetisation measurements establish the ferromagnetic nature of the Yb3+–Yb3+ coupling. We comment on the Yb3+ crystal field properties.
PACS: 75.50.Cc – Other ferromagnetic metals and alloys / 76.80.+y – Mössbauer effect
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2007