Evolution of phases in (Ba,Sr)Al4

Recent results have shown an emergence of CDW order in SrAl4 at 243K, together with a hysteretic structural transition at 87K from a tetragonal to potentially monoclinic structure. The tetragonal structure of BaAl4 with lattice parameters very close to SrAl4 invites a chemical substitution study to track the reported transitions. We have performed electrical resistivity and magnetic susceptibility measurements, along with x-ray and neutron scattering on the Ba1-xSrxAl4 family. All samples have been grown in self-flux and produce large single-crystals, seemingly limited by crucible size.