• Title/Summary/Keyword: Magnetic bilayer

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Temperature dependence of exchange bias in Co/Ni anti-dot arrays

  • Seo, M.S.;Deshpande, N.G.;Lee, S.J.;Lee, Y.P.;Rhee, J.Y.;Kim, K.W.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.436-436
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    • 2011

  • Recently, spintronic devices with submicron structures are widely investigated to take advantage of their unique micromagnetic properties. In this work, we study the temperature dependence of exchange bias in bilayer anti-dot arrays made by depositing Co (40 nm)/Ni (5 nm) ferromagnetic bilayer on Si substrate to form anti-dot arrays with a diameter $1{\mu}m$. The anti-dot patterning was done only for the upper Co layer, while the Ni underlayer was kept unperforated. The temperature dependences of magnetoresistance (MR) and exchange bias were studied along magnetic easy and hard axes. The in-plane MR measurements were performed using a physical-property measurement system (PPMS ; Quantum Design Inc.) at various temperatures. The standard in-line four-point probe configuration was used for the electrical contacts. As temperature was varied, the MR data were obtained in which in-plane field (H=3 kOe) was applied in the directions along the hard and the easy axes with respect to the lattice plane. The temperature dependences of magnetic anisotropy and exchange bias were also studied along the magnetic easy and hard axes. As temperature decreases, the single peak splits into two peaks. While no exchange bias was observed along the magnetic easy axis, the exchange bias field steadily increased with decreasing temperature along the magnetic hard axis. These results were interpreted in connection with the magnetic anisotropy and the effect of the anti-dots in pinning domain wall motion along the respective direction.

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Magnetic and transport properties of $La_{0.8}Sr_{0.2}MnO_3/La_{0.8}Ca_{0.2}MnO_3$ bilayer

  • Li, S.F.;Kim, J.B.;Hyun, Y.H.;Lee, Y.P.;Prokhorov, V.G.;Komashko, V.A.
    • Journal of Korean Vacuum Science & Technology
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    • v.7 no.1
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    • pp.8-12
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    • 2003

  • The effects of lattice strain on the magnetic and the transport properties of La$_{0.8}$Sr$_{0.2}$MnO$_3$films grown on a LaAlO$_3$ (001) substrate and on a La$_{0.8}$Sr$_{0.2}$MnO$_3$ layer have been studied. It was observed that the metal-insulator and the ferromagnetic transitions turn out to be at higher temperatures for the film deposited on La$_{0.8}$Sr$_{0.2}$MnO$_3$ layer with respect to that on LaAlO$_3$. The dependence of Curie temperature on the bulk and the Jahn-Teller strains has also been determined. determined.

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The Electronic and Magnetic Properties of Fe Overlayers on W(110) (W(110)위에 성장한 Fe 웃층의 전자 및 자기적 성질)

  • ;;A. J. Freeman
    • Journal of the Korean Magnetics Society
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    • v.1 no.2
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    • pp.1-8
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    • 1991

  • The electronic and magnetic structure of Fe overlayers on W(110) is determined by means of the all-electron local spin density full potential linearized augmented plane wave (FLAPW) method with a single slab approach. Charge and spin densities, magnetic moments, contact hyperfine fields, and layer projected density of states (LDOS) are presented. For bilayer Fe coverage, we find magnetic moments to be 2.90 and 2.30 ${\mu}_B$ for the surface and subsurface Fe layers, respectively, corresponding to a 18% enhancement of the total magnetization compared with the calculated bulk value (2.22${\mu}_B$);For monolayer coverage the moment is 2.56 ${\mu}_B$ which is enhanced by 16% compared to bulk. Unusual changes in the magnetic hyperfine interaction are found in going from a monolayer to a bilayer coverage. Comparison of the results to the theoretical ones of the clean Fe(110) to discuss the hybridization and the negative pressure effects. We discuss our results by comparing them to experimental results.

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