Antiferromagnetic Order in the Rare-Earth Halide Perovskites CsEuBr₃ and CsEuCl₃

Bulk CsEuBr$_3$ and CsEuCl$_3$ are experimentally shown to be magnetic semiconductors that order antiferromagnetically at Neel temperatures of 2.0 K 1.0 respectively. Given nanoparticles thin films have been reported ferromagnetically a similar temperature, our observation antiferromagnetic ordering in expands the possible applications halide perovskites now include spintronic devices where both ferromagnetic can fabricated from single material. The conclusion used as switchable material is also supported by density-functional theory calculations.