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The amorphous chalcogenide glass Sn1As20S79 is demonstrated to undergo permanent changes in refractive index on irradiation with ultraviolet light. The refractive properties of this material and the effect of annealing at temperatures below the glass transition temperature are investigated in detail. An Sn1As20S79 strip waveguide is fabricated using this photoinduced refractive index change, and the device is shown to function as expected with good propagation characteristics for the 632.8 nm guided mode. [ABSTRACT FROM AUTHOR]

Changes in the refractive index and thickness of amorphous As2S8 semiconductor film are observed under illumination, annealing–illumination, and annealing-illumination cycles. Properties of the As2S8 film are measured using techniques of prism coupler, x-ray diffraction spectra and Raman spectra. After light illumination the refractive index change in an as-deposited As2S8 film is one order of magnitude greater than that of an annealed As2S8 film, corresponding to ∼0.06 and ∼0.0057, respectively. Photoexpansions with a change in the relative film thickness of the as-deposited and annealed As2S8 film are nearly -3.5% and -2.1%, respectively, which exhibit the photodensification. The full reversibility of the photoinduced refractive index change is claimed on an annealed As2S8 film sample. [ABSTRACT FROM AUTHOR]

An unconventional method of nonlocal spin detection is demonstrated in mesoscopic lateral spin valves at room temperature. Clear nonlocal spin signals are detected between the two ends of an extended ferromagnetic spin detector. This is different from the conventional method in which the nonlocal voltage is measured between the spin detector and the nonmagnetic channel. The results can be understood as spatially non-uniform absorption of a pure spin current into the spin detector across a low-resistance oxide interface. [ABSTRACT FROM AUTHOR]

Cobalt/copper nonlocal spin valve devices with AlOx barriers are fabricated for the purpose of spin-transfer with a pure spin current. The submicron planar device consists of a Co spin injector (F1), a Co spin detector (F2), and a Cu channel. The F2 Co electrode is only 2.5 nm thick, but sizable nonlocal spin signals of 2–4 mΩ are measured at 4.2 K. The spin-transfer switching has been achieved with the assistance of a magnetic field. The magnetizations of F1 and F2 electrodes are set to an antiparallel state by sweeping the magnetic field. The magnetic field is then held at a value smaller but close to the switching field of F2. A small dc current (0.1–1 mA) is sufficient to switch F2 into being parallel with F1. Analysis has been done to rule out possible artifacts due to Oersted fields. [ABSTRACT FROM AUTHOR]

The effect of interface on the spin injection characteristics in lateral spin valves with Permalloy/MgO/Ag junctions has been studied. The spin valve signal drastically increases after the insertion of a thin MgO layer in the local and nonlocal spin injection schemes. We analyze our results based on the spin-dependent diffusion equation. This reveals that the interface resistance of ∼100 fΩm2 could effectively overcome the spin resistance mismatch between ferromagnetic and nonmagnetic metals. [ABSTRACT FROM AUTHOR]