Nuclear Magnetic Resonance and Magnetic Susceptibilities of Alloys of V with Al

Abstract

Nuclear magnetic resonance properties of the ${\mathrm{V}}^{51}$ and ${\mathrm{Al}}^{27}$ isotopes and magnetic susceptibilities are reported for V-Al alloys in the body-centered cubic region up to 40 at.% Al in V and in the intermetallic compound ${\mathrm{V}}_5$ ${\mathrm{Al}}_8$. In the bcc solid solution region the ${\mathrm{V}}^{51}$ Knight shift increases slightly from 0.567% in pure V to 0.586% in the 40 at.% Al alloy. The ${\mathrm{Al}}^{27}$ shift is negative, increasing from -0.038% at 5 at.% Al to -0.031% at 40 at.% Al. The magnetic susceptibility decreases monotonically from 287×${10}^{-6\mathrm{}}$ emu/mole for pure V to 160×${10}^{-6\mathrm{}}$ emu/mole for 35 at.% Al in V. These data, together with measured values of the electronic specific heat, are used to evaluate the various contributions to the Knight shift and susceptibility. It is shown that essentially all of the ${\mathrm{V}}^{51}$ Knight shift is the result of orbital paramagnetism, and that the latter accounts for most of the measured susceptibility in these alloys. The data support a band model in which the electrons in the $s-p$ band have little or no interaction with the $d$ band of the transition metal.