  The robustness of spin liquids with respect to small perturbations, and the
way magnetic frustration can be lifted by slight changes in the balance between
competing magnetic interactions remains a rich and open issue. We address this
question through the study of the Gadolinium Aluminium garnet
Gd$_3$Al$_5$O$_{12}$, a related compound to the extensively studied
Gd$_3$Ga$_5$O$_{12}$. We report on its magnetic properties at very low
temperature. We show that despite a freezing at about 300 mK, no magnetic
transition is observed, suggesting the presence of a spin liquid state down to
the lowest temperatures similarly to Gd$_3$Ga$_5$O$_{12}$, in spite of a larger
ratio between exchange and dipolar interactions. Finally, the phase diagram as
a function of field and temperature is strongly reminiscent from the one
reported in Gd$_3$Ga$_5$O$_{12}$. This study reveals the robust nature of the
spin liquid phase for Gd ions on the garnet lattice in stark contrast to Gd
ions on the pyrochlore lattice for which a slight perturbation drives the
compound into a range of magnetically ordered states.

Strongly Correlated Electrons;Materials Science