⁵¹V NMR Study of A15 Superconductor V₃Si

抄録

The Knight shift K and the spin-lattice relaxation rate 1/T₁ of ⁵¹V nuclei, and the macroscopic magnetic susceptibility have been measured in an A15 superconductor V₃Si. From the K-χ plot, the hyperfine coupling constant and the temperature independent Van Vleck term have been estimated. In the normal state, 1/T₁T decreases drastically with increasing temperature. In the superconducting state, 1/T₁ shows no coherence peak just below T_c(=17.1, K), and obeys the T³-law down to T_c/3, but deviates from it with decreasing temperature. It is shown that the temperature dependences of χ and 1/T₁T are well reproduced by the numerical calculation based on the narrow-band model at Fermi level, and that the band width should be much smaller than that given by the band calculation of Mattheiss and Weber. T₁TK²_d varies with temperature, which should also be explained with the narrow conduction band.