Reversible phase switching between antiferromagnetic SrCoO2.5 and ferromagnetic SrCoO3-δ by a flexible solid-state electrolyte gate

Manipulation of oxygen vacancies (V-o) in transition metal oxides (TMOs) can largely alter their physical and chemical properties, such as electrical conductivity, magnetic state, optical band-gap, and electrocatalytic reactivity. Many experimental and theoretical works have been conducted to study the formation/annihilation of V-o and its corresponding effect on the properties in TMOs. In this paper, a solid-state approach to modulate the oxygen stoichiometry in high quality SrCoOx epitaxial thin films was demonstrated. Dependence of the magnetic and electrical conducing properties on V-o was investigated. Room temperature reversible phase switching between brownmillerite antiferromagnetic insulating SrCoO2.5 and perovskite ferromagnetic metallic SrCoO3-delta was achieved by electric-field induced oxygen non-stoichiometry. This room temperature reversible phase switching indicates that SrCoOx thin films are a promising candidate for practical applications in resistive random access memory and spintronic devices.