辻岡 強

Readout characteristics have been investigated with a superlow-power readout method in order to solve the problem of information destruction caused by repeated readout operations in photon-mode photochromie memories. For ordinary photochromie diarylethene media, it was possible to read signals of about 105-106 cycles with this method. This method was also applied successfully to wavelength multiplexed recording. © 1995 The Japan Society of Applied Physics.

The mechanism of crosstalk in photon-mode multi-wavelength recording has been theoretically analyzed, and a new method to reduce the crosstalk is proposed in this paper. The crosstalk has linear components of superposition and nonlinear components due to intermodulation. Both can be reduced by linear and nonlinear mixing of the readout signals at lambda(i) (i = 1, 2,...). This reduction method was applied to photochromic optical media having two broad absorption bands which were superimposed with each other. Thus 2-wavelength recording (writing and reading) was achieved.

Theoretical analysis has been carried out to estimate the relationship between recording sensitivity and transfer rate, and possible readout repeatability for a photochromic memory medium (molar extinction coefficient, e, quantum yield of photoreaction, 4&gt ). Under typical conditions (εφ = 1000 1/mol • cm and recording laser power 10 mW (633 nm)), transfer rate of 10 Mbps and readout operation of more than 106 can be achieved by adopting a superlow-power readout method. © 1994 IOP Publishing Ltd.

The structure and magnetic properties of iron nitride thin films were examined with the substrate temperature as a parameter. The coercivity and squareness ratio decreased with increasing substrate temperature, while the saturation magnetization remained constant. SEM observations revealed that the columnar growth deteriorated at high substrate temperatures. M#x00F6 ssbauer measurements indicated that films consisted of γ’-Fe4N, ε-Fe2-3N and ζ-Fe2N, and that the concentrations of these components were nearly independent of the substrate temperature. Domain replacement was found to be dominant in films prepared at higher substrate temperatures, which implies a change in the paramagnetic distribution. These results suggest that the decrease in coercivity could be attributed to a reduction in the shape anisotropy due to the disordered growth of columns and to a decreased magnetic separation effect by paramagnetic phases in individual columns. © 1989 IEEE