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We have investigated how the surface magnetism of epitaxial La 0.67 Sr 0.33 MnO 3 films on NdGaO 3 substrates is modified by 2 nm-thick caps of the undoped manganite LaMnO 3 and the band insulator SrTiO 3 . Low-temperature photoemission electron microscopy images with x-ray magnetic circular dichroism contrast reveal large ferromagnetic domains, and a reduction of surface Curie temperature by 40 K (LaMnO 3 cap) and 70 K (SrTiO 3 cap). We use these negative results to argue that capped films of sub-optimally doped La 1− x Sr x MnO 3 ( x ≠0.33) should improve the operating temperature of all-oxide and other spintronic devices.

We investigate in detail the mechanisms of heat relaxation at a gold:water interface and address the effect of a polymer (DHLA-Jeffamine) coated at the surface. We demonstrate that above a low surface density limit, the adjunction of polymers significantly enhances the interface conductance from the metal to the fluid. From molecular dynamics simulations, we have computed the corresponding increase of thermal conductance. The physical origin of this effect is analyzed in terms of transmission spectra. Transient non-equilibrium simulations finally compare the profile of the thermal field generated with and without the polymer.

We have calculated the electric polarizability of two types of lipid bilayers, formed by 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipids. We demonstrate that despite the very similar chemical structures, the bilayers exhibit dramatically different terahertz infrared (IR) properties. We demonstrate that the chemical structure of the lipids influences the morphology of the bilayers, which in turn impacts their IR responses interestingly, both structures exhibit a non-uniform absorption. For the case of DPPC, the infrared absorption is mostly driven by the hydrophilic heads, whereas for the POPC lipids, the absorption occurs predominately at the hydrophobic tails. (C) 2015 AIP Publishing LLC.

High-resolution magnetoelectric imaging is used to demonstrate electrical control of the perpendicular local magnetization associated with 125 nm-wide magnetic stripe domains in 100-nm-thick Ni films. This magnetoelectric coupling is achieved in zero magnetic field using strain from ferroelectric BaTiO3 substrates to control perpendicular anisotropy imposed by the growth stress. These findings may be exploited for perpendicular recording in nanopatterned hybrid media.

Repeatable magnetization reversal under purely electrical control remains the outstanding goal in magnetoelectrics. Here we use magnetic force microscopy to study a commercially manufactured multilayer capacitor that displays strain-mediated coupling between magnetostrictive Ni electrodes and piezoelectric BaTiO(3)-based dielectric layers. In an electrode exposed by polishing approximately normal to the layers, we find a perpendicularly magnetized feature that exhibits non-volatile electrically driven repeatable magnetization reversal with no applied magnetic field. Using micromagnetic modelling, we interpret this nominally full magnetization reversal in terms of a dynamic precession that is triggered by strain from voltage-driven ferroelectric switching that is fast and reversible. The anisotropy field responsible for the perpendicular magnetization is reversed by the electrically driven magnetic switching, which is, therefore, repeatable. Our demonstration of non-volatile magnetic switching via volatile ferroelectric switching may inspire the design of fatigue-free devices for electric-write magnetic-read data storage.