A Novel Approach to Obtain GeSbTe-Based High Speed Crystallizing Materials for Phase Change Optical Recording

2001 ◽  
Vol 674 ◽  
Author(s):  
Tae-Yon Lee ◽  
Byung-ki Cheong ◽  
Taek Sung Lee ◽  
Sung Jin Park ◽  
Won Mok Kim ◽  
...  
Keyword(s):  
Phase Change ◽  
Data Storage ◽  
High Speed ◽  
Preliminary Test ◽  
Optical Data Storage ◽  
Optical Recording ◽  
Optical Data ◽  
Recording Layer ◽  
Novel Approach ◽  
Vegard’S Law

ABSTRACTA new approach is proposed to obtain fast crystallizing materials based on a conventional GeSbTe alloy for rewritable phase change optical data storage. By means of co-sputtering, Ge1Sb2Te4alloy was mixed with Sn1Bi2Te4alloy so as to form pseudo-binary alloys (Ge1Sb2Te4)1-x(Sn1Bi2Te4)x (x is a mole fraction). From structural and optical analyses of the co- sputtered and annealed alloy films, the formation of stable crystalline single phases was observed along with a Vegard's law behavior, suggesting a homogeneous mixing of the two alloys. By use of a 4 layered disk with (Ge1Sb2Te4)0.85(Sn1Bi2Te4)0.15 recording layer, a preliminary test of writing and erasing was carried out and the results were compared with the case of the disk with Ge1Sb2Te4recording layer. The (Ge1Sb2Te4)0.85(Sn1Bi2Te4)0.15 recording layer was found to yield markedly higher erasibility, especially with increasing disk linear velocity.

Thermal Conductivity Measurement of the ZnS-SiO2 Dielectric Films for Optical Data Storage Applications

2004 ◽  
Author(s):  
Chun-Teh Li ◽  
Yizhang Yang ◽  
Sadegh M. Sadeghipour ◽  
Mehdi Asheghi
Keyword(s):  
Thermal Conductivity ◽  
Temperature Distribution ◽  
Phase Change ◽  
Data Storage ◽  
Conductivity Measurement ◽  
Optical Data Storage ◽  
Optical Recording ◽  
Optical Data ◽  
Recording Technology ◽  
Dielectric Layers

The amorphous/crystalline phase formation during writing or erasure of the written marks, in the rewritable phase change (PC) optical recording media, is controlled by the temperature distribution in the media and its variation with time. Temperature distribution, on the other hand, strongly depends on the thermal properties of its constituent layers in particular the ZnS-SiO2 dielectric layer that separates the phase change media from the substrate and aluminum heat sink. The reported values for the thermal conductivity of thin dielectric layers are however limited in the literature. In this manuscript, we report thermal conductivity data for dielectric layers of thickness near 50, 100 and 225 nm using the steady sate Joule-heating and electrical resistance thermometry technique. The boundary resistance at the interface is estimated to be near 7.0×10−8 m2 K W−1, which would limit the thermal time constant for cooling of PC layer and potentially impact data rate and jitter in optical recording technology.

Aeroelastic Flutter of a Flexible Disk Rotating in an Enclosed Compressible Fluid

2003 ◽  
Author(s):  
Namcheol Kang ◽  
Arvind Raman
Keyword(s):  
Data Storage ◽  
Traveling Waves ◽  
Compressible Fluid ◽  
High Speed ◽  
Hard Disk Drives ◽  
Low Noise ◽  
Optical Data Storage ◽  
Optical Data ◽  
Acoustic Oscillations ◽  
Flexible Disk

The aeroelastic stability of a thin, flexible disk rotating in an enclosed compressible fluid is investigated analytically through a discretization of the field equations of a rotating Kirchhoff plate coupled to the acoustic oscillations of the surrounding fluid. The discretization procedure exploits Green’s theorem and exposes two different gyroscopic effects underpinning the coupled system dynamics: one describes the gyroscopic coupling between the disk and acoustic oscillations, and another arises from the disk rotation. The discretized dynamical system is cast in the compact form of a classical gyroscopic system and acoustic and disk mode coupling rules are derived. Effects of eigenvalue veering of structure and acoustic dominated modes are investigated in detail. For the undamped system, coupled structure-acoustic traveling waves can destabilize through mode coalescence leading to flutter instability. Regions in parameter space are identified where structure-acoustic traveling waves of specific wave numbers destabilize. The results are expected to be relevant for the design of high speed, low vibration, low noise hard disk drives and optical data storage systems.

Recent Progress of Electro-optic Polymers for Device Applications

1997 ◽  
Vol 488 ◽  
Author(s):  
Alex K-Y. Jen ◽  
Qing Yang ◽  
Seth R. Marder ◽  
Larry R. Dalton ◽  
Ching-Fong Shu
Keyword(s):  
Data Storage ◽  
High Speed ◽  
Stable State ◽  
Optical Data Storage ◽  
Device Fabrication ◽  
Optical Data ◽  
Material System ◽  
Electro Optic ◽  
Potential Applications ◽  
Device Applications

AbstractElectro-optic (E-O) polymers have drawn great interest in recent years because of their potential applications in photonics devices such as high speed modulators and switches, optical data storage and information processing1–2. In order to have suitable materials for device fabrication, it is essential to design and develop polymeric material systems (active and passive polymers) with matched refractive indices, large E-O coefficients, good temporal and photochemical stability3–8 The E-O response of an active polymer commonly arises from the electric field induced alignment of its second-order nonlinear optical (NLO) chromophore, either doped as a guest/host system or covalently bonded as a side-chain. Because of the strong interaction among the electric dipoles, the poled structure is in a meta-stable state; the poled NLO chromophores which possess large dipole moment will tend to relax back to the randomly oriented state. As a result, the stability of the poled structure strongly depends on the rigidity of the overall material system. As it might be expected, the continuous increases of the rigidity and Tg of poled polymers imposes constraints on the selection of suitable chromophores that can survive the hightemperature poling and processing conditions. To circumvent this problem, we have developed a series of chromophores that possess conformation-locked geometry and perfluoro-dicyanovinylsubstituted electron-accepting group which demonstrate both good thermal stabilty and nonlinearity. This paper provides a brief review of these highly efficient and thermally stable chromophores and polymers for device applications.

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