Density of states, compositional short-range order, and stability of amorphousZrxCu1−xalloys

We report on ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$, ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}$, and ${}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}$ NMR measurements of the metallic glass ${\mathrm{Zr}}_x{\mathrm{Cu}}_{1-x}$ ($0.38\le x\le 0.72$), studied together with magnetic measurements. We discuss our results in terms of a two-band model with local densities of states and show that the $d$-electron density of states increases with increasing $x$. The averaged quadrupole coupling constant was determined at the ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}$ and the ${}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}$ sites. From the concentration dependence of the ${}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}$ quadrupole coupling constant it was derived that near 70 at.% Zr appreciable compositional short-range order exists.