Effect of Au spacer layer on \u3ci\u3eL\u3c/i\u3e1\u3csub\u3e0\u3c/sub\u3e phase ordering temperature of CoPt thin films

We have studied the effect of Au on the ordering temperature of CoPt films. The coercivity of the CoPt multilayer with 2 nm Au inserted is around 5 kOe after annealing at 400 °C. This ordering temperature is about 200 °C lower than that of a pure CoPt film. Crystallographical analysis using x-ray diffraction has also revealed that the lattice constant is drastically changed around the same temperature, which is related to the formation of the L10-ordered structure. Thus, the Au plays an important role in reducing the ordering temperature

Effect of Au spacer layer on \u3ci\u3eL\u3c/i\u3e1\u3csub\u3e0\u3c/sub\u3e phase ordering temperature of CoPt thin films

We have studied the effect of Au on the ordering temperature of CoPt films. The coercivity of the CoPt multilayer with 2 nm Au inserted is around 5 kOe after annealing at 400 °C. This ordering temperature is about 200 °C lower than that of a pure CoPt film. Crystallographical analysis using x-ray diffraction has also revealed that the lattice constant is drastically changed around the same temperature, which is related to the formation of the L10-ordered structure. Thus, the Au plays an important role in reducing the ordering temperature

Adaptive Predictive Rate Control Algorithm for MPEG Videos by Rate Quantization Method

Several new rate quantization models were proposed for predicting the global behavior of the encoder over a large range of quantization step values. The proposed models were tested. One of the proposed models, a four parameter model, outperforms the rest and even achieved better prediction performance than a piecewise linear model with eight parameters. In local regions, predictive algorithm was proposed which reduces the computational complexity. Switching criteria are proposed that adoptively select the suitable rate quantization models used for a particular situation to minimize the computational complexity and the prediction error

Window-based fast search algorithm for image vector quantization

A novel codebook design algorithm is first proposed in this paper. The difference between the new algorithm and the conventional codebook design algorithm is the insertion of an ordering process. The resultant vector quantizer has better correlation preservation property which in turn leads to better coding performance. Moreover, the new algorithm naturally leads to a fast search method, namely a window-based fast search. The window-based fast search method not only accelerates the vector quantization process but also results in better rate-distortion performance

Magnetic Properties and Nanostructures of Composite

Nanocomposite CoχPt100100-χ :C thin films with χ = 57 and χ = 50 were prepared by magnetron sputtering. Structures and activation volumes were studied systematically in order to better understand the magnetic behavior.We found that activation volumes of these two samples were almost the same. However, physical grain sizes of these two samples were different. Magnetic grains in the sample with equiatomic Co and Pt composition were almost independently switched and magnetic grains in the sample with higher Co content were exchange coupled and switched together. The reduction of the physical grain size in the sample does not always cause the reduction of the exchange coupling in the sample. Our results indicate that the Co concentration is an additional factor to be used for controlling the properties of nanocomposite CoPt:C films

Magnetic intergranular interaction in nanocomposite Co\u3csub\u3eχ\u3c/sub\u3ePt\u3csub\u3e100-χ\u3c/sub\u3e:C thin films

Magnetization reversal and intergranular interactions have been studied in composite CoχPt100-χ:C thin films using several magnetic characterization techniques. The intergranular interactions, as determined by ΔM curves, were strongly dependent on the ratio of Co and Pt concentration. For films with high Co content, the intergranular exchange coupling was predominant, while dipolar interactions were exhibited in the film with the equiatomic concentration of Co and Pt. Magnetic intergranular interaction was directly observed using magnetic force microscopy. There is a strong correlation between the value of the ΔM and magnetic correlation length obtained from the magnetic domain images