Doping- and Strain-Dependent Electrolyte-Gate-Induced Perovskite to Brownmillerite Transformation in Epitaxial LaSrCoO Films.

Much recent attention has focused on the voltage-driven reversible topotactic transformation between the ferromagnetic metallic perovskite (P) SrCoO and oxygen-vacancy-ordered antiferromagnetic insulating brownmillerite (BM) SrCoO. This is emerging as a paradigmatic example of the power of electrochemical gating (using, , ionic liquids/gels), the wide modulation of electronic, magnetic, and optical properties generating clear application potential. SrCoO films are challenging with respect to stability, however, and there has been little exploration of alternate compositions.