Dynamic Coercivity and Thermal Decay of Magnetic Media

1998 ◽  
Vol 517 ◽  
Author(s):  
Kurt Rubin ◽  
Jason Goldberg ◽  
Hal Rosen ◽  
Ernesto Marinero ◽  
Mary Doemer ◽  
...  
Keyword(s):  
Time Dependence ◽  
Decay Rate ◽  
Experimental Technique ◽  
Linear Density ◽  
Magnetic Media ◽  
Magnetic Transitions ◽  
Thermal Decay ◽  
Thermally Induced ◽  
The Media ◽  
Short Times

AbstractThermally induced decay of longitudinally recorded magnetic transitions is measured on a spin-stand. The decay rate increases with increased linear density and decreases with increased media coercivity. A new spin-stand experimental technique has been developed which allows measurements of the time dependence of the media coercivity as a function of write times spanning short times characteristic of write times in drives to long times associated with VSM measurements. The ratio of long to short write time coercivity was larger for media which are thermally unstable.

Using the scanning electron microscope for failure analysis of high density magnetic media

1987 ◽  
Vol 45 ◽  
pp. 392-393
Author(s):  
Evelyn R. Ackerman ◽  
Gary D. Burnett
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Failure Analysis ◽  
High Density ◽  
Magnetic Media ◽  
Specific Data ◽  
Retrieval Systems ◽  
Operating Environments ◽  
The Media ◽  
Scanning Electron

Advancements in state of the art high density Head/Disk retrieval systems has increased the demand for sophisticated failure analysis methods. From 1968 to 1974 the emphasis was on the number of tracks per inch. (TPI) ranging from 100 to 400 as summarized in Table 1. This emphasis shifted with the increase in densities to include the number of bits per inch (BPI). A bit is formed by magnetizing the Fe203 particles of the media in one direction and allowing magnetic heads to recognize specific data patterns. From 1977 to 1986 the tracks per inch increased from 470 to 1400 corresponding to an increase from 6300 to 10,800 bits per inch respectively. Due to the reduction in the bit and track sizes, build and operating environments of systems have become critical factors in media reliability.Using the Ferrofluid pattern developing technique, the scanning electron microscope can be a valuable diagnostic tool in the examination of failure sites on disks.

scholarly journals Two ways for finding the thermal decay rate at weak friction

2019 ◽  
Vol 1260 ◽  
pp. 092001
Author(s):  
M V Chushnyakova ◽  
I I Gontchar ◽  
A I Blesman
Keyword(s):  
Decay Rate ◽  
Thermal Decay

scholarly journals Remotely sensed thermal decay rate: an index for vegetation monitoring

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
S. S. Kumar ◽  
L. Prihodko ◽  
B. M. Lind ◽  
J. Anchang ◽  
W. Ji ◽  
...  
Keyword(s):  
Decay Rate ◽  
Remotely Sensed ◽  
Thermal Decay ◽  
Vegetation Monitoring

Thermally induced time dependence of mechanical properties in biomedical grade polyurethanes

1979 ◽  
Vol 13 (2) ◽  
pp. 189-206 ◽  
Author(s):  
G. L. Wilkes ◽  
T. S. Dziemianowicz ◽  
Z. H. Ophir ◽  
E. Artz ◽  
R. Wildnauer
Keyword(s):  
Mechanical Properties ◽  
Time Dependence ◽  
Thermally Induced

Photochromism of spiroindolinonaphthoxazine. I. Photophysical properties

1983 ◽  
Vol 61 (2) ◽  
pp. 300-305 ◽  
Author(s):  
Nori Y. C. Chu
Keyword(s):  
Decay Rate ◽  
Photophysical Properties ◽  
Ultraviolet Region ◽  
Colored Form ◽  
Thermal Decay ◽  
Triplet Energy ◽  
Absorption Bands ◽  
Different Temperatures ◽  
Transfer Method ◽  
Triplet Energy Transfer

A solution of spiroindolinonaphthoxazine in a common organic solvent shows profound photochromic effect. The colorless form in ethanol displays three absorption bands (~320, 235, 203 nm) in the ultraviolet region of the spectrum. The absorption spectrum of the colored metastable form shows two prominent absorption peaks at 612 and 578 nm. The triplet state energy level of the colorless form is estimated to be in the range from 2.4 × 104 to 2.1 × 104 cm−1 by the triplet–triplet energy transfer method. There exists a thermal equilibrium between the colorless and colored forms. From the measurement of absorbance of the colored form at different temperatures, the standard enthalpy of equilibrium is obtained (ΔH0 = 1500 cm−1). The thermal decay of the colored form to the colorless form depends strongly on temperature. The decay rate increases three times for every 10 °C increase in temperature. From these temperature dependence studies of the thermal decay rate, the thermal energy barrier for the colored metastable state to decay to the colorless form is determined to be 6.9 × 103 cm−1.

scholarly journals Concerning the time dependence of the decay rate of 137Cs

2013 ◽  
Vol 74 ◽  
pp. 50-55 ◽  
Author(s):  
J.H. Jenkins ◽  
E. Fischbach ◽  
D. Javorsek ◽  
R.H. Lee ◽  
P.A. Sturrock
Keyword(s):  
Time Dependence ◽  
Decay Rate

The Effect of Structural Relaxation on the Diffusion of Au in Amorphous Pd80Si20

1992 ◽  
Vol 279 ◽  
Author(s):  
A. V. Wagner ◽  
F. Spaepen
Keyword(s):  
Time Dependence ◽  
Viscous Flow ◽  
Concentration Profile ◽  
Structural Relaxation ◽  
Rutherford Backscattering Spectrometry ◽  
New Method ◽  
Relaxation Model ◽  
Sputter Deposited ◽  
Kinetics Of ◽  
Short Times

ABSTRACTThe diffusivity of Au in sputter-deposited amorphous Pd80Si20 has been measured by Rutherford backscattering spectrometry (RBS) between 275°C and 380°C. A new method based on scaling of the evolution of the variance of the concentration profile was used to analyze the data. The diffusivity was found to be independent of the Au concentration below 3 at.%. Structural relaxation causes a time dependence that is evident at short times. The kinetics of this relaxation can be described by the bimolecular relaxation model used in the analysis of viscous flow.

Numerical investigation of tunnelling contributions to electron scavenging reactions in liquids at short times

1977 ◽  
Vol 55 (11) ◽  
pp. 2124-2132 ◽  
Author(s):  
P. Robin Butler ◽  
Michael J. Pilling ◽  
Stephen A. Rice ◽  
Timothy J. Stone
Keyword(s):  
Diffusion Equation ◽  
Time Dependence ◽  
Numerical Investigation ◽  
Concentration Profile ◽  
Electron Concentration ◽  
Significant Contribution ◽  
Reaction Parameters ◽  
Sink Term ◽  
Short Time ◽  
Short Times

Fick's second diffusion equation, with an added exponential sink term, is integrated numerically to simulate the decay of electrons at short times in the presence of scavengers. The time dependence of the scavenger concentration profile, the scavenging rate constant, and the electron concentration are illustrated graphically. Using the experimental results of Buxton et al. and Jonah et al. It is shown that the Smoluchowski equation is valid within their experimental time ranges provided the cage encounter distance is replaced by Reff, where Reff can be evaluated explicitly in terms of reaction parameters. It is also shown that tunnelling from relaxed traps may make a significant contribution to ultra-short time electron scavenging.

Systematic variation of thiophene substituents in photochromic spiropyrans

2017 ◽  
Vol 16 (7) ◽  
pp. 1057-1062
Author(s):  
Dushanthi S. Dissanayake ◽  
Gregory T. McCandless ◽  
Mihaela C. Stefan ◽  
Michael C. Biewer
Keyword(s):  
Decay Rate ◽  
Half Life ◽  
Reverse Reaction ◽  
Systematic Variation ◽  
Synthetic Method ◽  
Thermal Decay

A new synthetic method was developed to incorporate spiropyran into thiophene based materials via a conjugated pathway. As the number of thiophene units increased, the thermal decay rate of the reverse reaction decreased in methanol, thus increasing the half-life of merocyanine.

Sign in / Sign up

Export Citation Format

Share Document