Super-Resolution Optical Disc with High Readout Stability Using a Zinc Oxide Thin Film

Abstract

The linear thermal expansion, AC susceptibility and magnetostriction have been measured on a single crystal of HoA12. Our results clearly show two phase transitions associated, respectively, with establishment of magnetic order and with spontaneous spin reorientation. The critical exponent ySR of the susceptibility for l-3 TSR has been determined. From magnetostriction measurements along the major symmetry directions of the crystal, we have obtained the possible deformation modes compatible with the point symmetry of the cubic crystal structure. A complete study of the magnetoelastic behaviour has allowed us to determine the reduced magnetoelastic coupling coefficients M : / C y , M i / C ' , M f / C " (I = 4,6)and D"/C".Themodelusedisbasedonasingle-ionorigin for the crystal electric field interaction of the rare-earth ion, and we have taken into account the spontaneous reorientation of the magnetic moment in the molecular field, which represents the exchange interaction.

Readout durability improvement of super-resolution near-field structure disc using germanium nitride interface layers

“…However, it was still 75,000 times for 100-nm monotone marks (using HD DVD based optics) until carrier-to-noise ratio (CNR) decreases 3 dB from the original value over 40 dB (at the readout laser power, P r = ~3 mW). Previous studies have shown better durability results (100,000 times) that can be achieved by using ZnO as a material for the super-resolution readout [4] and by lowering P r condition of a super-RENS disc (P r = 1.5 mW) [5]. In this study, we did not replace Sb-Te (Sb 75 Te 25 ) to other readout materials since it shows better super-resolution performance [6], and we intended to find another way of improving the durability that is also applicable to high P r condition (~3 mW).…”

Decision Feedback Partial Response Maximum Likelihood for Super-Resolution Media

“…Developments in super-resolution (SR) media beyond the diffraction limit have made considerable progress. [1][2][3][4] The carrier-to-noise ratios (C/Ns) of these media are sufficient for double density Blu-ray discs (BDs). However, bit error rates (bERs) that are practical for actual systems are unsatisfactory for the production of a disc with density of 50 Gbytes per disc.…”

Bit-Error-Rate Evaluation of Energy-Gap-Induced Super-Resolution Read-Only-Memory Disc with Dual-Layer Structure

“…nergy-gap-induced super-resolution (EG-SR) technique using a zinc oxide (ZnO) film has been proposed as a promising way to obtain an areal density higher than that of current commercial Blu-ray Discs (BD). [1][2][3][4] We already reported that a single-layer 40 gigabytes (GB) EG-SR read-only-memory (ROM) disc with a tantalum (Ta) reflective film shows a good bit error rate (bER) and wide tolerances in disc tilts and focus offset. 5) In this paper, we report that a dual-layer 80 GB EG-SR ROM disc shows practically available characteristics including readout power characteristics, readout cyclability, tilt margins, and focus offset margins.…”