The ultraviolet photoluminescence of ZnO/ZnGa 2 O 4 composite layer grown by the thermal oxidation of ZnS with gallium was investigated by the time-resolved photoluminescence as a function of measuring temperature and excitation power. With increase of excitation power, the D 0 X emission is easily saturated than the DAP emission from ZnO/ZnGa 2 O 4 composite layer, and which is dramatically enhanced as compared with that from pure ZnO layer grown without gallium. The radiative recombination process with ultra-long lifetime controlled the carrier recombination of ZnO/ZnGa 2 O 4 composite layer. C 2014 Author(s)

Spin-to-charge conversion is an essential requirement for the implementation of spintronic devices. Recently, monolayers of semiconducting transition metal dichalcogenides (TMDs) have attracted considerable interest for spin-to-charge conversion due to their high spin-orbit coupling and lack of inversion symmetry in their crystal structure. However, reports of direct measurement of spin-to-charge conversion at TMD-based interfaces are very much limited. Here, we report on the room temperature observation of a large spin-to-charge conversion arising from the interface of Ni80Fe20 (Py) and four distinct large area (∼ 5 × 2 mm 2 ) monolayer (ML) TMDs namely, MoS2, MoSe2, WS2, and WSe2. We show that both spin mixing conductance and the Rashba efficiency parameter (λIREE) scales with the spin-orbit coupling strength of the ML TMD layers. The λIREE parameter is found to range between −0.54 and −0.76 nm for the four monolayer TMDs, demonstrating a large spin-tocharge conversion. Our findings reveal that TMD/ferromagnet interface can be used for efficient generation and detection of spin current, opening new opportunities for novel spintronic devices.

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Epitaxial Fe thin films were grown on annealed MgO(001) substrates at oblique incidence by DC magnetron sputtering. Due to the oblique growth configuration, uniaxial anisotropy was found to be superimposed on the expected four-fold cubic anisotropy. A detailed study of in-plane magnetic hysteresis for Fe on MgO thin films has been performed by Magneto Optic Kerr Effect (MOKE) magnetometer. Both single step and double step loops have been observed depending on the angle between the applied field and easy axis i.e. along ⟨100⟩ direction. Domain images during magnetization reversal were captured by Kerr microscope. Domain images clearly evidence two successive and separate 90° domain wall (DW) nucleation and motion along cubic easy cum uniaxial easy axis and cubic easy cum uniaxial hard axis, respectively. However, along cubic hard axis two 180° domain wall motion dominate the magnetization reversal process. In spite of having four-fold anisotropy it is essential to explain magnetization reversal mechanism in 0°< ϕ < 90° span as uniaxial anisotropy plays a major role in this system. Also it is shown that substrate rotation can suppress the effect of uniaxial anisotropy superimposed on four-fold anisotropy.