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Electrical manipulation of lattice, charge, and spin is realized respectively by the piezoelectric effect, field-effect transistor, and electric field control of ferromagnetism, bringing about dramatic promotions both in fundamental research and industrial production. However, it is generally accepted that the orbital of materials are impossible to be altered once they have been made. Here, electric field is used to dynamically tune the electronic-phase transition in (La,Sr)MnO3 films with different Mn4+/(Mn3+ + Mn4+) ratios. The orbital occupancy and corresponding magnetic anisotropy of these thin films are manipulated by gate voltage in a reversible and quantitative manner. Positive gate voltage increases the proportion of occupancy of the orbital and magnetic anisotropy that were initially favored by strain (irrespective of tensile and compressive), while negative gate voltage reduces the concomitant preferential orbital occupancy and magnetic anisotropy. Besides its fundamental significance in orbital physics, these findings might advance the process towards practical oxide-electronics based on orbital. [ABSTRACT FROM AUTHOR]

The electronic phase transition has been considered as a dominant factor in the phenomena of colossal magnetoresistance, metal-insulator transition, and exchange bias in correlated electron systems. However, the effective manipulation of the electronic phase transition has remained a challenging issue. Here, the reversible control of ferromagnetic phase transition in manganite films through ionic liquid gating is reported. Under different gate voltages, the formation and annihilation of an insulating and magnetically hard phase in the magnetically soft matrix, which randomly nucleates and grows across the film instead of initiating at the surface and spreading to the bottom, is directly observed. This discovery provides a conceptually novel vision for the electric-field tuning of phase transition in correlated oxides. In addition to its fundamental significance, the realization of a reversible metal-insulator transition in colossal magnetoresistance materials will also further the development of four-state memories, which can be manipulated by a combination of electrode gating and the application of a magnetic field. [ABSTRACT FROM AUTHOR]

C. Song, F. Pan, and co‐workers demonstrate reversible ferromagnetic phase transition in electrode‐gated manganites on page 7233. The formation and annihilation of an insulating and magnetically hard phase in soft magnetic matrix, which randomly nucleates and grows across the film, is directly observed in manganite by ionic‐liquid‐gating. The realization of reversible metal‐insulator transition in colossal‐magnetoresistance materials would advance four‐state memories. [ABSTRACT FROM AUTHOR]