Si-29 NMR and relaxation in FeSi

Corti M., Aldrovandi S., Fanciulli M., Tabak F.

PHYSICAL REVIEW B, vol.67, no.17, 2003 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 67 Issue: 17
  • Publication Date: 2003
  • Doi Number: 10.1103/physrevb.67.172408
  • Journal Name: PHYSICAL REVIEW B
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Hacettepe University Affiliated: No

Abstract

Si-29 NMR spectra and spin-lattice relaxation measurements in FeSi at different magnetic fields ranging from 1.6 to 15 T, from 1.6 K up to 900 K, are reported. The spin-lattice relaxation rate T-1(-1) and the Knight shift K-S display very interesting temperature dependences, with three different regimes. At low temperatures (Tless than or equal to100 K) T-1(-1) increases linearly on increasing temperature while K-S is practically constant. In the intermediate temperature range (100less than or equal toTless than or equal to350 K) T-1(-1) shows a behavior typical of a gapped system, with an energy gap Deltasimilar or equal to560 K and tracking the homogeneous static susceptibility chi(T). For Tgreater than or equal to350 K the temperature dependence of T-1(-1) departs from that of the susceptibility. While chi(T) levels around 500 K, T-1(-1) continues to increase. From the experimental findings, insights on the spin dynamics of Fermi-like carriers with strong correlation are obtained.