Nuclear magnetic resonance study of Li implanted in a thin film of niobium

Abstract

We report results of beta-detected NMR of 8 Li + implanted in Nb at high magnetic field. We identify two distinct sites for 8 Li in the body-centered lattice. At low temperature, the site is characterized by a well-defined quadrupolar splitting. At about 50 K this site becomes unstable. Close to room temperature, Li occupies the cubic substitutional site. Spin-lattice relaxation measurements are consistent with a site-dependent coupling to the Nb conduction electrons and suggest that the site change proceeds in two steps. We report Knight shifts for the two well-defined sites and perform a Korringa analysis.

Local metallic and structural properties of the strongly correlated metal LaNiO3 using 8Li β–NMR

“…However, an essential feature of our data is the two component character of the relaxation indicating two metallic local environments for the 8 Li. Based on the β-NMR of 8 Li in simple metals, 22,38,[42][43][44][45][46] one possibility is simply that there are two inequivalent sites for the implanted 8 Li within the unit cell. In elemental Ag and Au, 22,38,44 for example, there are two cubic 8 Li sites that differ in their hyperfine coupling to the conduction band, and we find a T dependent site change transition around 180 K. 44 In other perovskite oxides, [34][35][36] we find a single interstitial 8 Li + site characterized by a large quadrupole splitting, 34,35,37 which we shall call the P site, at the 3c Wyckoff position in the cubic (Pm 3m) phase.…”

Finite-size effects in the nuclear magnetic resonance of epitaxial palladium thin films

“…We collect spectra with both senses of nuclear spin polarization, i.e., the initial nuclear spin state is nearly either |m = +2 or |−2 , so that the outer satellites, (±2 ↔ ±1) are dominant, and they are found on opposite sides of the central frequency in the two helicities. Examples of this include BCC Niobium 28 and SrTiO 3 , 20 both cubic crystals where the interstitial site of the 8 Li + is noncubic with a finite electric field gradient (EFG) yielding a quadrupole split NMR. Among the FCC metals, we have never found a quadrupolar splitting for 8 Li.…”

β-NMR of 8Li+ in rutile TiO2

“…The asymmetric time-integrated asymmetries from spin-polarization with different helicities (A ± ) are characteristic of a quadrupole split resonance [17,19]. From the combined asymmetry (A), we find a broad, 12.48 ± 0.12 kHz wide quadrupole split resonance with unresolved features.…”