발간논문

Home > KJMM 논문 > 발간논문

We explore the possibility of sputtered Bi thin film applicable for the spin device by investigating the change in microstructure and magneto-resistance (MR) of post-annealed Bi film. Randomly oriented fine grains of which size was measured to about 100 nm (nano meter) were found in as-sputtered Bi. Careful annealing done at only 1.4℃ below the melting temperature of Bi results in not only grain growth up to 1.2 pm but also textured grains well aligned to [003] preferred orientation of Bi. The MR for as-sputtered Bi film was hardly observed regardless of measuring temperature, whereas those of annealed were found to reach 30,000% at 4 K and 600% at 300 K respectively. The drastic change in MR after annealing is largely attributed to the significant grain growth decreasing grain boundary scattering as well as to the trigonal-axis oriented microstructures diminishing anisotropy scattering of moving electron. Our results demonstrate sputtered Bi thin film can be usable for spintronic devices by employing a suitable post annealing treatment. (Received March 29, 2004)

keyword : Bismuth, Sputter, Semimetal, Magnetoresistance, MR, Spintronics

In this study, a new electrochemical state reaction is defined to describe aqueous solutions in the mixed atmosphere of hydrogen and oxygen. In zinc-water system, new irreversible electro reactions are deduced by applying the new electrochemical state reaction of water to zinc under dynamic potential changes. From those irreversible electro reactions, a new potential-pH diagram is depicted. It is able to expound that meta stable zinc oxide in the unstable range of pH is formed on zinc anode and cathode in zinc ion or zincate solutions because of the asymmetric changes of activities of water, hydrogen and hydroxide ions on the electrodes by polarization. (Received January 8, 2004)

keyword : Zinc, Electro, Potential, pH, Diagram