The advent of spin transfer torque effect accommodates site-specific switching of magnetic nanostructures by current alone without magnetic field. However, the critical current density required for usual spin torque switching remains stubbornly high around 10(6)-10(7) A cm(-2). It would be fundamentally transformative if an electric field through a voltage could assist or accomplish the switching of ferromagnets. Here we report electric-field-assisted reversible switching in CoFeB/MgO/CoFeB magnetic tunnel junctions with interfacial perpendicular magnetic anisotropy, where the coercivity, the magnetic configuration and the tunnelling magnetoresistance can be manipulated by voltage pulses associated with much smaller current densities. These results represent a crucial step towards ultralow energy switching in magnetic tunnel junctions, and open a new avenue for exploring other voltage-controlled spintronic devices.

The Skyrmion state in epitaxial B20 FeGe(111) thin films, determined by the topological Hall effect, is greatly extended in the phase diagram to cover all temperatures up to the Curie temperature T(C)≈271 K and over a wide magnetic field range that includes a zero magnetic field. The properties of the Skyrmion phase can be controlled and manipulated by the film thickness, which has a strong effect on the stabilization of Skyrmions.

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The etching of the more active component from a homogeneous alloy is important in corrosion reactions and has been exploited in the synthesis of high surface area nanoporous materials. In this paper we show that nanoporous films can be obtained by selective electrochemical etching of the more noble component in a system where the more active component is passivated. We demonstrate that nanoporous nickel films can be obtained by a two-step process involving electrodeposition of a homogeneous Ni x Cu 1-x alloy followed by electrochemical etching of the copper from the alloy. The composition, lattice parameter, saturation magnetization, and Curie temperature of the electrodeposited Ni x Cu 1-x alloys can be precisely controlled by varying the deposition conditions. Nanoporous nickel can be formed by electrochemically etching the copper from the alloy. The nanoporous structures are characterized by a three-dimensional network of interconnected pores and exhibit enhanced coercivity and reduced magnetic anisotropy. The morphology of the nanoporous nickel films is dependent on the initial composition of the Ni x Cu 1-x alloy.

Thin Pt films on an yttrium iron garnet (YIG = Y(3)Fe(5)O(12)) show ferromagneticlike transport properties, which may impact the functionality of Pt in spin current detection, but do not provide direct quantitative information on the Pt magnetization. We report magnetic x-ray magnetic circular dichroism measurements of YIG/Pt(1.5 nm) showing an average Pt moment of 0.054 μ(B) at 300 K and 0.076 μ(B) at 20 K. This observation indicates strong proximity effects and induced magnetic ordering in Pt on magnetic insulators and their contribution to the spin-related measurements should not be neglected. The transport characteristics also suggest considerable modifications in the Pt electronic structure due to magnetic ordering.