Lvkuan Zou

Angular Dependence of Exchange Bias and Magnetization Reversal Controlled by Electric‐Field‐Induced Competing Anisotropies

The combination of exchange-biased systems and ferroelectric materials offers a simple and effective way to investigate the angular dependence of exchange bias using one sample with electric-field-induced competing anisotropies. A reversible electric-field-controlled magnetization reversal at zero magnetic field is also realized through optimizing the anisotropy configuration, holding promising applications for ultralow power magnetoelectric devices.

Magnetic tuning of the photovoltaic effect in silicon-based Schottky junctions.

A magnetic tuning of the photovoltaic effect is demonstrated for the Schottky junction formed by a ferromagnetic (FM) layer and silicon. Obvious anisotropic magnetic photovoltaic effects (AMV) are gained not only in the FM layer but also in the Si substrate though the latter is non-magnetic. Key factors determining the AMV of Si are identified.

Electric-Field Modulation of Interface Magnetic Anisotropy and Spin Reorientation Transition in (Co/Pt)3/PMN–PT Heterostructure

We report electric-field control of magnetism of (Co/Pt)3 multilayers involving perpendicular magnetic anisotropy with different Co-layer thicknesses grown on Pb(Mg,Nb)O3-PbTiO3 (PMN-PT) FE substrates. For the first time, electric-field control of the interface magnetic anisotropy, which results in the spin reorientation transition, was demonstrated. The electric-field-induced changes of the bulk and interface magnetic anisotropies can be understood by considering the strain-induced change of magnetoelastic energy and weakening of Pt 5d-Co 3d hybridization, respectively. We also demonstrate the role of competition between the applied magnetic field and the electric field in determining the magnetization of the sample with the coexistence phase. Our results demonstrate electric-field control of magnetism by harnessing the strain-mediated coupling in multiferroic heterostructures with perpendicular magnetic anisotropy and are helpful for electric-field modulations of Dzyaloshinskii-Moriya interaction and Rashba effect at interfaces to engineer new functionalities.

Spin Hall Angle and Spin Diffusion Length in Au–Cu Alloy

We experimentally measured the fieldlike spin-orbit torque (SOT) by the second-order planar Hall effect, as well as the dampinglike SOT by the polar magnetooptic Kerr effect in NiFe(1.5 nm)/AuCu(x nm) bilayers with 2 nm ≤ x ≤ 8 nm. We found that the spin diffusion length in the Au-Cu alloy is ~5 nm, which is shorter than that of pure Au and Cu. When the thickness of the AuCu layer is above the spin diffusion length, the spin Hall angle of the Au-Cu alloy is ~1.3 ± 0.2%, which is much larger than that of pure Cu and Au. The results imply that large spin Hall angle materials can be explored in the nonmagnetic alloys of constituent elements having weak or negligible spin-orbit coupling.

Joule heating-induced coexisted spin Seebeck effect and spin Hall magnetoresistance in the platinum/Y3Fe5O12 structure

Spin Seebeck effect (SSE) and spin Hall magnetoresistance (SMR) are observed simultaneously in the Pt/Y3Fe5O12 hybrid structure when thermal gradient is produced by Joule heating. According to their dependences on applied current, these two effects can be separated. Their dependence on heating power and magnetic field is systematically studied. With the increase of heating power, the SSE enhances linearly, whereas the SMR decreases slowly. The origin of the spin currents is further analyzed. The heating power dependences of the spin currents associated with the SSE and the SMR are found to be different.

Ferroelectric Materials: Angular Dependence of Exchange Bias and Magnetization Reversal Controlled by Electric‐Field‐Induced Competing Anisotropies (Adv. Mater. 2/2016)

Y. Zhao and co-workers demonstrate a simple and effective method to investigate the angular dependence of exchange bias using one sample with different ratios and relative orientations of the anisotropies via the combination of exchange-biased systems and ferroelectric materials. As they describe on page 363, electric-field-controlled magnetization reversal without a bias magnetic field is also realized at room temperature in this system through electric-field-induced competing anisotropies.