Voltage‐Controlled Deblocking of Magnetization Reversal in Thin Films by Tunable Domain Wall Interactions and Pinning Sites. (16th September 2020)

• Record Type: Journal Article
• Authors: Zehner, Jonas; Soldatov, Ivan; Schneider, Sebastian; Heller, René; Khojasteh, Nasrin B.; Schiemenz, Sandra; Fähler, Sebastian; Nielsch, Kornelius; Schäfer, Rudolf; Leistner, Karin
• Is Part Of: Advanced Electronic Materials. Volume 6:Number 11(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-09-16
• Subjects: iron films -- magnetic domains -- magnetoelectrics -- magneto‐ionic mechanisms -- Néel walls; Materials -- Electric properties -- Periodicals; Materials science -- Periodicals; Magnetic materials -- Periodicals; Electronic apparatus and appliances -- Periodicals; 537
• DOI: 10.1002/aelm.202000406
• Languages: English
• ISSNs: 2199-160X

Abstract

Abstract: High energy efficiency of magnetic devices is crucial for applications such as data storage, computation, and actuation. Redox‐based (magneto‐ionic) voltage control of magnetism is a promising room‐temperature pathway to improve energy efficiency. However, for ferromagnetic metals, the magneto‐ionic effects studied so far require ultrathin films with tunable perpendicular magnetic anisotropy or nanoporous structures for appreciable effects. This paper reports a fully reversible, low voltage‐induced collapse of coercivity and remanence by redox reactions in iron oxide/iron films with uniaxial in‐plane anisotropy. In the initial iron oxide/iron films, Néel wall interactions stabilize a blocked state with high coercivity. During the voltage‐triggered reduction of the iron oxide layer, in situ Kerr microscopy reveals inverse changes of coercivity and anisotropy, and a coarsening of the magnetic microstructure. These results confirm a magneto‐ionic deblocking mechanism, which relies on changes of the Néel wall interactions, and of the microstructural domain‐wall‐pinning sites. With this approach, voltage‐controlled 180° magnetization switching with high energy‐efficiency is achieved. It opens up possibilities for developing magnetic devices programmable by ultralow power and for the reversible tuning of defect‐controlled materials in general. Abstract : Voltage‐induced magnetic deblocking by redox reactions in iron oxide/iron films results in a reversible collapse of coercivity and remanence. The analysis of the inverse changes of coercivity and anisotropy, and the magnetic domains reveals modulations of the Néel wall interactions, and of the microstructural domain‐wall‐pinning sites as the origin. The estimated switching energy for 180° magnetization reversal is promising for ultralow power devices.