Optically Induced Phase Change for Magnetoresistance Modulation

Abstract

Optical methods for magnetism manipulation have been considered as a promising strategy for ultralow‐power and ultrahigh‐speed data storage and processing, which have become an emerging field of spintronics. However, a widely applicable and efficient method has rarely been demonstrated. Here, the strongly correlated electron material vanadium dioxide (VO2) is used to realize the optically induced phase change for control of the magnetism in NiFe. The NiFe/VO2 bilayer heterostructure features appreciable modulations of electrical conductivity (32%), coercivity (37.5%), and magnetic anisotropy (25%). Further analyses indicate that interfacial strain coupling plays a crucial role in the magnetic modulation. Utilizing this heterostructure, which can respond to both optical and magnetic stimuli, a phase change controlled anisotropic magnetoresistance (AMR) device is fabricated, and reconfigurable Boolean logics are implemented. As a demonstration of phase change spintronics, this work may pave the way for next‐generation opto‐electronics in the post‐Moore era.

Reversible Switching of Interlayer Exchange Coupling through Atomically Thin VO2 via Electronic State Modulation

“…In addition to extending the platforms for in situ IEC control, this work, based on electronic state modulations of the VO 2 spinterface, may provide a widely applicable, all-solid, and multiply triggered solution to optimize spintronic effects and implement device functions. 27…”

Tuning Spin‐Orbit Torques Across the Phase Transition in VO2/NiFe Heterostructure

“…At the VO 2 insulating regime, the spin-orbit torque arises from the selfinduced torque of the NiFe layer, while as the VO 2 becomes more metallic across the phase transition, the bulk and the negative spin Hall effect from the VO 2 dominates and reverses the spin-orbit torque direction. Finally, there may be a contribution to the torque originating in the interfacial scattering, but we expect that the interfacial contribution does not change drastically across the insulatormetal transition since the strain induced by the structural phase transition is small (typically of ≈1% [27] ).…”

“…Finally, there may be a contribution to the torque originating in the interfacial scattering, but we expect that the interfacial contribution does not change drastically across the insulator–metal transition since the strain induced by the structural phase transition is small (typically of ≈1% [ 27 ] ).…”

“…The hysteretic phase transition allows to deliberately switch between insulating and metallic states, which can then influence the current flow and thus spin-orbit effects. The change in the VO 2 orbital occupation [22] across the structural phase transition leads to the large changes in electrical resistivity [23] as well as optical, [24] structural, [25] and magnetic properties [26][27][28] and is expected to affect the spin-orbit coupling directly. [29] However, the effect of the VO 2 phase transition on current-induced spin-orbit torques in a VO 2 /ferromagnet heterostructure, which is of key importance for the future functionalization, has not been investigated and therefore is the main focus of this study.…”

Voltage-Controlled ON–OFF-Switching of Magnetoresistance in FeOx/Fe/Au Aerogel Networks

“…Tuning the MR by an external parameter is important for the functionality of many devices. Control of MR via electric current, light, , or thermal stimuli is often hampered by small effects, low energy efficiency, or complex device design. A more promising approach is to use voltage as a control parameter, offering both high energy efficiency and easy applicability. − Voltage-controlled MR in a thin film geometry has been demonstrated by using multiferroic heterostructures, − capacitive charging − and, more recently, magneto-ionics. − …”