E Pavarini et al 2003 Supercond. Sci. Technol. 16 147 doi:10.1088/0953-2048/16/2/303
E Pavarini1, S H Baek2, B J Suh3, F Borsa1,2, S L Bud'ko2 and P C Canfield2
Show affiliationsWe have performed 11B NMR measurements in 11B enriched MgB2 powder sample in the normal phase. The Knight shift was accurately determined by using the magic angle spinning technique. Results for 11B and 27Al Knight shifts (K) and relaxation rates (1/T1) are also reported for AlB2. The data show a dramatic decrease of both K and 1/T1 for 11B in AlB2 with respect to MgB2. We compare experimental results with ab initio calculated NMR relaxation rates and Knight shifts. The experimental values for 1/T1 and K are in most cases in good agreement with the theoretical results. We show that the decrease of K and 1/T1 for 11B is consistent with a drastic drop of the density of states at the boron site in AlB2 with respect to MgB2.
76.60.Cq Chemical and Knight shifts
74.25.Nf Response to electromagnetic fields (nuclear magnetic resonance, surface impedance, etc.)
74.70.Ad Metals; alloys and binary compounds (including A15, MgB2, etc.)
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
Issue 2 (February 2003)
Received 29 June 2002
Published 30 December 2002
E Pavarini et al 2003 Supercond. Sci. Technol. 16 147
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