Magnetic and structural properties of the solid solution CuAlGaO.

CuAlO is a ternary oxide spinel with Cu ions ([Formula: see text]) primarily populating the A-site diamond sublattice. The compound is reported to display evidence of spin glass behavior but possess a non-frozen magnetic ground state below the transition temperature. On the other hand, the spinel CuGaO displays spin glass behavior at ~ 2.5 K with Cu ions more readily tending to the B-site pyrochlore sublattice. Therefore, we investigate the magnetic and structural properties of the solid solution CuAlGaO examining the evolution of the magnetic behavior as Al is replaced with a much larger Ga ion. Our results show that the Cu ions tend to migrate from tetrahedral to octahedral sites as the Ga ion concentration increases, resulting in a concomitant change in the glassy magnetic properties of the solution. Results indicate glassy behavior for much of the solution with a general trend towards decreasing magnetic frustration as the Cu ion shifts to the B-site. However, the [Formula: see text] and 0.2 members of the system do not show glassy behavior down to our measurement limit (1.9 K) suggesting a delayed spin glass transition. We suggest that these two members are additional candidates for investigation to access highly frustrated exotic quantum states.