Electron spin resonance ofNd3+andGd3+

Abstract

We report on the ESR of the rare-earth ions Nd +, Gd +, Er +, and Yb + on powdered samples of various intermetallic compounds of AB2 cubic structure where 8 is a transition-metal ion belonging to the group VIII of the Periodic Table, and A is a nonmagnetic ion (La, Ce, 'Y). The resonance of the Nd + in these compounds originates within a 16 crystal-field ground level and exhibits resolved hyperfine satellites for the ' Nd and ' Nd isotopes. The Gd + spectra show a single isotropic line. Using our data for Gd + and Nd + together with results previously published for the AB2 cubic compounds, we were able to show a correlation between the observed g shifts and the position of the 8 ion in the Periodic Table. This variation is explained qualitatively using a simple multiband model, as well as band-structure arguments. The hyperfine constants for the Nd and ' 5Nd isotopes were found smaller in magnitude with respect to the values in insulators; this effect is attributed to s-electron self-polarization due to the Nd localized-moments-electron exchange coupling. The ESR linewidths of LaIr2'. Nd and LaRh2'. Nd exhibit an exponential thermal dependence at high temperatures which is attributed to the presence of a I 8 excited level at 5 =-90+ 20 K.

Magnetic field dependence and bottlenecklike behavior of the ESR spectra inYbRh2Si2

“…This analysis does not consider any direct Yb 3+ spin-phonon contribution. 18 The S and Q-band ⌬H͑T͒ data for 7 Շ T Շ 20 K also show exponential behaviors with c Ϸ 200͑70͒Oe/ K and ␦ Ϸ 75͑20͒ K. ␦ Ϸ 65͑30͒ K. 18 The inset of Fig. 3͑a͒ includes b͑͒ for the S and Q bands and inset of Fig.…”

“…The third is the relaxation, also via an exchange interaction with the ͑ce͒, of a thermally populated Yb 3+ excited crystal-field state at ␦ K above the ground state. 18 The fitting parameters are in the inset of Fig. 2͑a͒.…”

“…Therefore, these results definitely indicate that the T dependence of the effective g͑x , T͒ is nothing but a consequence of the shift of the field for resonance toward higher fields due to an AF internal molecular field and has nothing to do with a ⌬g = c / ln͑T K / T͒ divergence. 6 Moreover, the expected g shift caused by the exchange interaction between the Yb 3+ and ce local moments J fce can be estimated from the largest measured Korringa-rate value ͑unbottleneck͒, b Х 40 Oe/ K. Within a single band approximation 18 and absence of q dependence of the Yb 3+ -ce exchange interaction J fce ͑q͒ Х J fce ͑0͒, 23 one can write ͑⌬g / g͒ 2 = B b / gk B , which gives ͉⌬g / g͉ Շ 2%. This value is far much smaller than that estimated in Ref.…”

ESR ofGd3+in the Kondo-lattice compoundYbAgCu4

“…21,22 The electronic contribution to the heat capacity of these compounds yields to the ␥ values shown in Table I. In a free c-e gas model ␥ϭ(2/3) 2 k 2 (E F ).…”

Electron spin resonance ofGd3+andNd3+Pagliuso1, Rettori2, Sarrao3 et al. 1999Phys. Rev. BSelf Cite170100View full textAdd to dashboardCite

“…5 It has been suggested that a negative effective exchange for RE impurities in some d-band compounds is due to the lack of orthogonality between the 4 f and d-orbitals of the neighbor sites. 5,6 The purpose of this paper is to show that ESR of Gd 3ϩ and Nd 3ϩ in the LuInA 4 (AϭCu,Ni) compounds can provide a means to probe the band structure of these systems. We showed that the ESR data of Gd 3ϩ in LuInCu 4 ͑Ref.…”