Oxide Spintronics as a Knot of Physics and Chemistry: Recent Progress and Opportunities

Abstract

Transition-metal oxides (TMOs) constitute a key material family in spintronics because of mutually coupled degrees of freedom and tunable magneto-ionic properties. In this Perspective, we consider oxide spintronics as a knot of physics and chemistry and mainly discuss two current hot topics: spin−charge interconversion and magneto-ionics. First, spin−charge interconversion is focused on oxide films and heterostructures including 4d/5d heavy metal oxides (e.g., SrIrO 3 ) and two-dimensional electron gases. Based on spin−charge interconversion, charge currents can be transformed to spin currents and generate spin−orbit torque in oxide/metal and alloxide heterostructures. Additionally, the voltage control of magnetism in TMOs by the magneto-ionic pathway has rapidly accelerated during the past few years due to the versatile advantages of effective control, nonvolatile nature, low power cost, etc. Typical magneto-ionic oxide systems and corresponding physicochemical mechanisms will be discussed. Finally, further developments of oxide spintronics are envisioned, including material discovery, physics exploration, device design, and manipulation methods.

Engineering of Electromechanical Oxides by Symmetry Breaking

“…A robust cross‐length scale modeling approach is therefore required. 6)Substantive spectroscopic evidence for defect types and densities at interfaces, which can provide unambiguous identification based on local structural information, is yet to be established. 7)For the foreseeable future, the dependence of material properties on the reduction of film thickness will remain a key hurdle toward obtaining more promising electromechanical materials. 8)The role of symmetries in the kinetics and dynamics of electromechanical materials is yet to be fully established. 9)Ferroelectric field control of material symmetry, which could yield new phenomena as a result of the strong coupling between chirality, spin, valley, etc. [ 145–147 ] …”

“…9) Ferroelectric field control of material symmetry, which could yield new phenomena as a result of the strong coupling between chirality, spin, valley, etc. [145][146][147] Research in the field of symmetry breaking in centrosymmetric materials is still in its infancy with regards to our fundamental understanding of the various mechanisms. Numerous interesting questions remain open and, no doubt, several new materials and structures are yet to be elaborated and discovered.…”

Strain-Induced Uphill Hydrogen Distribution in Perovskite Oxide Films

“…Ionic control of transition-metal oxides (TMOs) has become an effective pathway to tune functionalities including magnetic, − electronic, − optical, − thermoelectric, , and catalytic performances. − As the smallest ion, H + (proton) is naturally endowed with high mobility, excellent reversibility, prominent modulation effect, and broad applicability to binary and complex oxides. − In recent years, increasing efforts have been put into developing facile hydrogenation methods − and discovering novel properties in protonated phases. − Owing to the tight relationship between hydrogen (doping) concentration, lattice, and electronic structure, understanding the migration mechanism and detecting the spatial distribution of H + are necessary for finely tailoring the physical properties on a microscopic scale and enhancing the reaction efficiency of the energy-conversion process in protonic ceramic fuel cells. ,,− A typical example is the construction of reconfigurable NdNiO 3 electronic devices (artificial neurons, synapses, and memory capacitors) via the sensitivity of electronic properties to the local distribution of H + …”

Fast-Charging Degradation Mechanism of Two-Dimensional FeSe Anode in Sodium-Ion Batteries

“…First, most in situ techniques have difficulty in obtaining valuable information in an extremely short charging time for the unsatisfactory temporal resolution . Second, most TMCs transform into amorphous phases after the initial cycle and hardly produce diffraction peaks in XRD or neutron diffraction patterns, which hinders the effectiveness of traditional in situ techniques. , It is worth noting that the magnetism of TMCs is sensitive to their electron transfer during the sodiation/desodiation process, which makes in situ magnetometry highly valuable in monitoring the dynamic evolution process of TMCs. − Moreover, since magnetism is a real-time reflection of the electronic state of TMCs, in situ magnetometry is almost free from information hysteresis and amorphous phase undetectability . In particular, in situ magnetometry can provide quasi-quantitative information on the premise that the sodiation/desodiation process of TMCs is accompanied by the generation or consumption of a ferromagnetic phase .…”