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Results on both field driven and current induced domain wall motion in Co/Cu/Ni80Fe20 trilayered half-ring in-series wires with different linewidths were presented. The switching behavior depends linearly on the linewidth of Co/Cu/Ni80Fe20 trilayered half-ring structures. A larger bias field (Hb) applied to the samples results in a smaller critical current needed to reverse magnetization. The critical current density was observed to be 3×107 A/cm2 for Ni80Fe20 and 2×108 A/cm2 for Co at zero field. The results of the numbers of giant magnetoresistance jump (digital) versus external magnetic field and current densities (analog) of this design have potential utility as an analog-digital converter. [ABSTRACT FROM AUTHOR]

We prepared giant magnetoresistance samples comprising of pseudo spin valve structures and measured the current-perpendicular-to-plane magnetoresistance (MR) with applied magnetic field along the easy and hard axes of the samples. When the magnetic field was applied along the easy axis, high and low resistance states representing magnetization parallel and anti-parallel states were observed. However, when the magnetic field was applied along the hard axis, two stochastic MR curves were obtained. The two distinct MR curves correspond to the different magnetizations reversal processes via two kinds of the magnetization orientation states, fully parallel and anti-parallel, at remanence. In our case, the two distinct magnetization reversal processes occurred randomly. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate high-performance giant magnetoresistive spin transistor (GMRST) and magnetotunneling resistive spin transistor (MTRST) which could be used as magnetic pickup head and magnetoresistive random access memory (MRAM). This kind of spin device is based on the technologies of giant magnetoresistance (GMR) and tunneling magnetoresistance (TMR) effects together with a p-n junction. The junction is used as a potential barrier to select spin electrons. In case of GMRST the collector current, Ic, varies from 464 pA at magnetically parallel state to 309 pA at magnetically antiparallel state and gives a percentage change of about 50% at room temperature. As for the MTRST, the change of Ic is about 45% at room temperature with current varying from 2.9 to 4.2 μA. Memory effect, which is the intrinsic behavior of magnetic materials, is also demonstrated. [ABSTRACT FROM AUTHOR]

Polycrystalline single phase (La2-xSrx)MnO4 (1.10≤x≤1.40) samples were prepared by a citrate precursor method. They have tetragonal K2NiF4 structure with a space group of 14/mmm, increasing x, unit-cell a-axis increases and c-axis decreases, which is a result of decreasing of the Jahn-Teller effect due to the increase of the Mn(IV) ion. Spin glass state exists at low temperature and a hump observed from the susceptibility (χ) measurement is probably caused by the interactions of several magnetic phases. Among them, (La0.6Sr1.4)MnO4 has the largest magnetoresistance ratio ([ρ(H)-ρ(0)]/ρ(0)), which reaches to 78.4% at 48 K. It is not possible to obtain single phase materials with 0.60≤x≤1.00 in the heat treatment temperature range of 1000-1600°C. Impurities were easily observed under SEM and X-ray diffraction patterns. Increasing the heating period and decreasing the temperature, the amount of ABO3 perovskite phase increases. In order to extend the solubility range, of the SrO in the (La2-xSrx)MnO4, it probably needs a higher temperature (>1600°C) and a shorter heat treatment period (<1 h). [ABSTRACT FROM AUTHOR]

We examine the effects of modifying the Co hard layer thickness of Co/Cu/Co spin valve submicron pillars with current flowing perpendicular to the plane. The magnetoresistance (MR) ratios and switching currents show complementary behaviors. As the Co hard layer thickness is increased, the MR ratio shows an initial increase with a peak around 21 nm. The critical switching current shows a dip around the same thickness, which is close to the spin diffusion length. The product of the MR ratio and critical current density is about a constant independent of the Co hard layer thickness. Thus, we provide an approach to achieving maximum efficiency (MR ratio) and minimum consumption (critical current) for a practical device. [ABSTRACT FROM AUTHOR]

A spin transistor which consists of a metallic giant magnetoresistance emitter, a copper base, and a p-n junction was prepared on a Si(100) wafer. The emitter current changes from 1 mA at a magnetically parallel state to 0.968 mA at a magnetically antiparallel state. At the same states the base currents were 29.3 μA and 333 nA, respectively, which gave a magnetocurrent ratio of ∼8600% and a transfer ratio of 3×10-2 at room temperature for a common collector configuration. The sensitivity of this spin device is higher than 4000%/Oe. The memory effect and the high performance make it possible for practical usage. The working principle of this kind of three-terminal spin device can be simply described by circuit theory. [ABSTRACT FROM AUTHOR]

We study the spin dependent transport at the junctions between two superconducting Nb leads connected by two ferromagnetic NiFe bars in parallel, which have various separations. The separation distance l between NiFe bars was varied from 150 to 700 nm to study the spin relaxation effect in Nb. In small l (150 and 250 nm) samples, a spin-valve-like behavior related to the inverse proximity effect was observed, which manifest itself as charge accumulation due to spin imbalance near the interface. However, for samples with large l, the spin-valve behavior vanishes and the anisotropic magnetoresistance effect dominates. [ABSTRACT FROM AUTHOR]