Spin-Glass Behavior in L${\mathrm{a}}_{1.96}$S${\mathrm{r}}_{0.04}$Cu${\mathrm{O}}_4$

We report magnetization measurements in ${\mathrm{La}}_{1.96}{\mathrm{Sr}}_{0.04}{\mathrm{CuO}}_4$, which has neither antiferromagnetic long range order nor superconductivity. All the features that characterize a canonical spin-glass transition are seen: irreversibility, remnant magnetization, and scaling behavior. The magnetic moment arises from a small density of effective free spins.