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Femtosecond laser processing technology has been used to achieve controlled processing of microtips array on the surface of polycrystalline LaB6 blocks. Under the condition of ensuring the integrity of the geometric morphology of the tips array, the tips with a height of 10 μm and a radius of curvature of 1 μm can be processed. The distribution of tips in the array is uniform, the morphology is complete, the crystal structure and physical phase of LaB6 have not changed after processing, which breaks through the technical problems of difficult processing and poor geometry consistency about polycrystalline rare-earth hexaboride tips emitter, and the processing area is no longer limited by the small size of single crystals. The field emission performance test indicated that the turn-on electric field is 2.8 V/μm, and the current density is 467.9 mA/cm2 when the applied electric field reached 9.4 V/μm. [ABSTRACT FROM AUTHOR]

Field-effect transistors based on semiconductor integration technology have come to a bottleneck, while electric field control of magnetism has great potential for applications in next-generation magnetic memory and calculators based on electron spins. Magnetic properties manipulation from a mechanism of ion migration driven by an electric field has the advantages of low energy consumption, nonvolatility, reproducibility, and durability. Here, we introduce a solid-state integratable hydrogen ion storage electrolyte silicon phosphate as the gate to achieve reversible control of magnetoresistance, magnetism, and magnetic interaction in the La1−xSrxMnO3/SrTiO3 ferromagnetic system. The controllable double-exchange interaction and spin scattering mechanism sketch the theoretical physical picture for these results. This work is expected to open up additional opportunities in the translation of electric control of magnetism into practical applications. [ABSTRACT FROM AUTHOR]

Field-effect transistors based on semiconductor integration technology have come to a bottleneck, while electric field control of magnetism has great potential for applications in next-generation magnetic memory and calculators based on electron spins. Magnetic properties manipulation from a mechanism of ion migration driven by an electric field has the advantages of low energy consumption, nonvolatility, reproducibility, and durability. Here, we introduce a solid-state integratable hydrogen ion storage electrolyte silicon phosphate as the gate to achieve reversible control of magnetoresistance, magnetism, and magnetic interaction in the La1−xSrxMnO3/SrTiO3 ferromagnetic system. The controllable double-exchange interaction and spin scattering mechanism sketch the theoretical physical picture for these results. This work is expected to open up additional opportunities in the translation of electric control of magnetism into practical applications. [ABSTRACT FROM AUTHOR]

A field-emission microtips array with a radius of curvature, height, and separation distance of 0.5, 5, and 4 μm, respectively, was processed on the single-crystal Gadolinium hexaboride ceramic (GdB 6) (100) plane using a femtosecond laser. The height and morphology of the microtips array were uniform, and the crystal structure and phase composition of GdB 6 did not change after the processing. According to the field-emission performance test of a GdB 6 microtips array, the turn-on electric field intensity was 1.9 V/μm, and the field-emission current density reached 0.49 A/cm2 when the applied electric field strength was 6.7 V/μm; meanwhile, it had outstanding field-emission stability. Subsequently, the transmission process of the field-emission current of the GdB 6 between the cathode and the anode was simulated using COMSOL Multiphysics 5.6 software. The transmission process of the electron beam from emitters to the anode surface was divided into three stages due to the interaction between emission electrons and a magnetic field generated by its motion, including divergence, pinch, and drift. The increase of electric field strength reduced the radial displacement of the electron beam while moving the beam waist further away from the anode surface. The simulation results provide theoretical guidance for regulating the shape of the field-emission electron beam, size, and energy. [ABSTRACT FROM AUTHOR]

• The magnetic properties of α-Fe 2 O 3 and Fe 3 O 4 cannot be control by electric field. • The α-Fe 2 O 3 /Fe 3 O 4 composite structure is obtained by vacuum annealing of the α-Fe 2 O 3. • The magnetic properties of α-Fe 2 O 3 /Fe 3 O 4 can be reversibly and non-volatilely modulated. • The electric control of magnetism is due to the mechanism of phase transition. The raw nano α-Fe 2 O 3 powders consisting of nanorods with 50–100 nm in length and 8–14 nm in width exhibit superparamagnetism. The vacuum annealing of the raw nano α-Fe 2 O 3 at 400 °C for 3 h leads to ferromagnetic-like behaviors at room temperature (RT), due to the appearance of ferrimagnetic Fe 3 O 4. The α-Fe 2 O 3 /Fe 3 O 4 composite structure has an antiferromagnetic α-Fe 2 O 3 layer and a ferrimagnetic Fe 3 O 4 layer contains a certain amount of Fe2+ and oxygen vacancies. In addition, nano α-Fe 2 O 3 annealed in H 2 at 300 °C for 3 h completely become Fe 3 O 4. Some magnetic properties of the α-Fe 2 O 3 /Fe 3 O 4 , such as magnetization, magnetic remanence (Mr), coercivity (Hc) and exchange bias (EB), can be modulated almost reversibly and non-volatilely by applied external RT electric field without loop current. However, for both the raw nano α-Fe 2 O 3 and the Fe 3 O 4 , these magnetic properties cannot be modulated by applied external RT electric field. The electric field control of magnetic properties for the α-Fe 2 O 3 /Fe 3 O 4 should be due to the mechanism of phase transition induced by migration and redistribution of oxygen vacancies within the interface of α-Fe 2 O 3 /Fe 3 O 4. [ABSTRACT FROM AUTHOR]

Abstract The realization of strong magnetoelectric (ME) coupling for efficiently controlling of magnetism is urgently needed but still a significant challenge. Based on first-principle calculations and effective Hubbard models, we demonstrated that the polar charges and locality of edge states in hexagonal BN nanoribbons (BNNRs) play key roles in the behavior of edge magnetism M. By applying a transverse electric field, the magnetism in both zigzag and armchair edges can be regulated sufficiently. In particular, the magnetic on/off switches can be realized in armchair edges, it is robust against various edge decorations including hydrogenation, fluoridation and hydroxylation. Furthermore, uniaxial tensile strains can also produce significant magnetic modulation in Z -BNNRs, which stem from the piezoelectricity. All these suggest that h-BNNRs are ideal platforms for ME coupling researching and promising candidates for functional spintronics application. Graphical abstract Unlabelled Image Highlights • The bulk polarization is revealed to play important role in the edge magnetism in BN nanoribbons. • On/off magnetic switches can be realized in armchair BN nanoribbons via applying electric field. • Curie temperature can also be tuned by electric field. • Edge chemical decorations by H-, F- and HO- cannot eliminate the magnetic switches. • Strain effects can also be attributed to magnetoelectric coupling. [ABSTRACT FROM AUTHOR]

Abstract The Ag/copper oxide film/Nb:SrTiO 3 /Ag device exhibits the resistive switching accompanied with the electric field control of ferromagnetism. The ferromagnetism could also be modulated by ultraviolet and violet light with certain frequency at room temperature. The bipolar resistive switching in Ag/copper oxide film/Nb:SrTiO 3 /Ag device may depend on the change in a Schottky-like barrier height. In the same saturation current, we can change the sweeping voltage to get a different resistance change ratio. The changes of sweeping voltage will affect the Schottky-like barrier height, resulting in the resistance switching. The accompanying electric field control of ferromagnetism is mainly from the changes in the amount of oxygen vacancies in copper oxide film when the resistance state changes. The light-modulated ferromagnetism may be due to the enhancement of indirect double exchange. The capture of photo-generated holes by Cu+ may lead to changes in valence of some Cu ions, affecting the indirect double exchange. Through the resistive switching and ferromagnetism modulation in this report, it is possible to achieve the multi-state memory in future work. [ABSTRACT FROM AUTHOR]

• The reversible and non-volatile manipulation of magnetism. • The insertion and extraction of Li+ and H+ in MgFe 2 O 4 under electric field. • Changes of the Fe valence and layer spacing by the ions migration. • Organic lithium citrate has the advantages of convenience, safety, and low cost. Electric-field control of magnetism has attracted much attention in the field of information storage and spintronics. Based on Li+ and H+ ions migration under electric field, the manipulation of magnetic properties in MgFe 2 O 4 films has the advantage of non-volatility, reversibility and cyclicity. This work shows that the magnetism and coercivity are adjusted by the migration of alkali metal ions under electric field at 300 K, which shows great future potential for applications. [ABSTRACT FROM AUTHOR]