Magnetic memories

Murray KS, Kepert CJ (2004) Cooperativity in Spin Crossover Systems Memory, Magnetism and Microporosity. 233 195-228... 

Cooperativity in Spin Crossover Systems Memory, Magnetism and Microporosity 217... 

E Series Central Processor 85 Mbyte Fixed Disc 320 Kwords Memory Magnetic Tape Unit 4 Graphics Terminals 3 Non-Graphics Terminals Plotter... 

Finally, reconstructed images are stored in the refresh memory, magnetic disk, or magnetic tape, depending on the amount of storage, transfer rate, access time, cost, and other factors. 

In electron spin echo relaxation studies, the two-pulse echo amplitude, as a fiinction of tire pulse separation time T, gives a measure of the phase memory relaxation time from which can be extracted if Jj-effects are taken into consideration. Problems may arise from spectral diflfrision due to incomplete excitation of the EPR spectrum. In this case some of the transverse magnetization may leak into adjacent parts of the spectrum that have not been excited by the MW pulses. Spectral diflfrision effects can be suppressed by using the Carr-Purcell-Meiboom-Gill pulse sequence, which is also well known in NMR. The experiment involves using a sequence of n-pulses separated by 2r and can be denoted as [7i/2-(x-7i-T-echo) J. A series of echoes separated by lx is generated and the decay in their amplitudes is characterized by Ty. ... 

The most important mass memories use magnetic media in the form of magnetic tapes or disks (floppy disk and hard disk). Laser addressed optical mass memories are of increasing commercial importance. 

The question as to whether and to what extent and in what area optical mass storage would replace magnetic systems (disk, tape) was controversially being discussed in the 1980s. In spite of all predictions of an imminent substitution, as of late 1994 magnetic hard disks stiU are the system of choice for computer-dedicated mass storage due to their speed (access time, transfer rate), physical size, and energy consumption this is especially tme when memory-intensive appHcations are mn which use the hard disk as virtual memory. 

There is no competitive situation for data storage disks with embossed iaformation (CD-ROM) and recordable/nonerasable disks (WORM) no counterpart to CD-ROM and WORM exists among magnetic memories. EOD drives are best compared to floppies and removable hard disk media given their possibiUty of easy and problem-free disk exchange and a capacity on the order of that of removable magnetic media (Tape, Bernoulli, SyQuest). 

The acceptance of optical data storage iato the mass storage market, which is as yet exclusively dominated by magnetic systems, will be fundamentally boosted if optical drives and media are subject to uniform standards and become fully compatible, and multiuser drives are offered which enable the user to employ alternatively CD-ROM and EOD disks, and maybe WORM disks as well (and CD-R disks, respectively). A prerequisite, however, will be whether rewritable optical memories will use the MOR or the PCR process. This accord especially will be hard to reach. 

Generally it can be said that optical systems will assume an ever increasing market share (depending on the achievement of uniform standards) of the data storage market which is currently dominated by magnetic systems. Additionally they will advance iato new appHcations. Up to the end of the twentieth century, complementary technologies rather than a conflict between optical and magnetic mass memories are likely. 

Electrically Functional. Refractory coatings are used in semiconductor devices, capacitors, resistors, magnetic tape, disk memories, superconductors, solar ceUs, and diffusion barriers to impurity contamination from the substrate to the active layer. 

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