Posted on 04/04/2013 10:21:41 AM PDT by Ernest_at_the_Beach
Researchers at the U.S. Department of Energy’s Ames Laboratory, Iowa State University, and the University of Crete in Greece have found a new way to switch magnetism that is at least 1000 times faster than currently used in magnetic memory technologies. Magnetic switching is used to encode information in hard drives, magnetic random access memory and other computing devices. The discovery possibly opens the door to 1THz and faster memory speeds.
In current magnetic storage and magneto-optical recording technology, magnetic field or continuous laser light is used. For example, photo-excitation causes atoms in ferromagnetic materials to heat up and vibrate, and the vibration, with the help of a magnetic field, causes magnetic flips. The flips are part of the process used to encode information. But the speed of such thermal magnetic switching is limited by how long it takes to vibrate the atoms, and by how fast a magnetic field can reverse magnetic regions. It is very difficult to exceed the gigahertz (109Hz) switching speed limit of today’s magnetic writing/reading technology.
“The challenge facing magnetic writing, reading, storing and computing is speed, and we showed that we can meet the challenge to make the magnetic switches think ultra-fast in the femtosecond range – one quadrillionth of a second – by using quantum ‘tricks’ with ultrashort laser pulses,” said Jigang Wang, an assistant professor of physics and astronomy at Iowa State University and the physicist at Ames Laboratory.
As a result, some scientists have turned their attention to colossal magnetoresistive (CMR) materials because they are highly responsive to the external magnetic fields used to write data into memory, but do not require heat to trigger magnetic switching.
(Excerpt) Read more at xbitlabs.com ...
Bump for coolness factor.
My first corporate PC did not have a hard drive. Just two 5 1/4" floppies. Had to load the software (Lotus 1-2-3) each time. And the file size could not exceed 64k. Had to put a separate cartridge into the HP printer and about a 32 character string to print landscape.
I should feel old but I don't.
Thanks, Ernest.
I love being dazzled by new technology.
Real basic research....far off stuff.
Getting porn to users faster.
***********************************EXCERPT******************************************
Colossal magnetoresistance (CMR) is a property of some materials, mostly manganese-based perovskite oxides, that enables them to dramatically change their electrical resistance in the presence of a magnetic field. The magnetoresistance of conventional materials enables changes in resistance of up to 5%, but materials featuring CMR may demonstrate resistance changes by orders of magnitude.
Initially discovered in mixed-valence perovskite manganites in the 1950s by G. H. Jonker and J. H. van Santen.,[1] a first theoretical description in terms of the double-exchange mechanism was given early on. In this model, the spin orientation of adjacent Mn-moments is associated with kinetic exchange of eg-electrons. Consequently, alignment of the Mn-spins by an external magnetic field causes higher conductivity. Relevant experimental work was done by Volger,[2] Wollan and Koehler,[3] and later on by Jirak et al.[4] and Pollert et al.[5]
However the double exchange model did not adequately explain the high insulating-like resistivity above the transition temperature.[6] In the 1990s, work by R. von Helmholt et al.[7] and Jin et al.[8] initiated a large number of further studies. Although there is still no complete understanding of the phenomenon, there is a variety of theoretical and experimental work providing a deeper understanding of the relevant effects.
One prominent model is the so-called half-metallic ferromagnetic model, which is based on spin-polarized (SP) band structure calculations using the local spin-density approximation (LSDA) of the density functional theory (DFT) where separate calculations are carried out for spin-up and spin-down electrons. The half-metallic state is concurrent with the existence of a metallic majority spin band and a nonmetallic minority spin band in the ferromagnetic phase.
This model is not the same as the Stoner Model of itinerant ferromagnetism. In the Stoner model, a high density of states at the Fermi level makes the nonmagnetic state unstable. With SP calculations on covalent ferromagnets, the exchange-correlation integral in the LSDA-DFT takes the place of the Stoner parameter. The density of states at the Fermi level does not play a special role.[9] A significant advantage of the half-metallic model is that it does not rely on the presence of mixed-valency as does the double exchange mechanism and it can therefore explain the observation of CMR in stoichiometric phases like the pyrochlore Tl2Mn2O7. Microstructural effects have also been investigated for polycrystalline samples and it has been found that the magnetoresistance is often dominated by the tunneling of spin polarized electrons between grains, giving rise to an intrinsic grain-size dependence to the magnetoresistance.[10][11]
Hitherto, however, a fully quantitative understanding of the CMR effect has been elusive and it is still the subject of current research activities. Early prospects of great opportunities for the development of new technologies have not yet come to fruition.
***************************************EXCERPT****************************************
A NIMS research group has discovered a new material, NaCr2O4, which displays a novel type of colossal magnetoresistance effect. The new material was developed by ultra-high pressure synthesis.
Materials in which electrical resistance changes by an order of magnitude when a magnetic field is applied are called colossal magnetoresistance (CMR) materials. Virtually all known CMR materials are oxides of manganese, and their CMR mechanism also depends on a special ferromagnetic-metallic phase of manganese ions. However, new CMR mechanisms and material search guidelines which do not rely on manganese oxides have been demanded.
In this research, a new material, NaCr2O4, was developed by ultra-high pressure synthesis, focusing on the following two points: (1) Calcium ferrite structures have both a 1-dimensional crystal structure and a structure which displays magnetic frustration, and (2) oxides with tetravalent ions of Cr have a special electronic state.
It was found that a CMR effect occurs in NaCr2O4, which is not a ferromagnetic metal, but rather, is an antiferromagnetic semiconductor. Although the CMR effect appears over a wide temperature range, i.e., the entire temperature range below the magnetic transition temperature, this is a CMR effect with a new mechanism, which has the novel feature of not displaying history effects with respect to temperature or the magnetic field.
This result has important implications for the search for CMR materials, as it is also necessary to consider the antiferromagnetic semiconductors, which had seemed unrelated to the CMR effect until now. The new mechanism proposed as a result of this research has the potential to become a new material search guideline, as the CMR effect can be considered to occur in the diverse structures of various transition metal compounds.
It’ll still take Windows about 2 minutes to boot up.
Now, I can go to Target and pick up an Ipod with orders of magnitude more storage and processing horsepower. They're what, less than a couple of hundred bucks? , completely disposable, and I'd carry one in my pocket to play music when I feel the need to be amused.
Technology never ceases to amaze me.
It’ll still take Windows about 2 minutes to boot up.
I have a SSD (solid state Drive) and windows only takes 8 seconds to boot all the way up!!!!!
Remember when you had to go get your morning coffee while your desktop booted? And new software came on 10-20 floppies? And the only network was sneakernet?
Now do you feel old? I do. ;p
I had an IBM AT. Two 80mb hard drives. A math co-processor. An 80 mb tape drive so I could get data from the mainframe. It cost $15,000.
In college I used keypunch cards for data input into a SPSS program. There were no PSs
I do feel a little older now.
Perhaps these findings will lead to rather fast hard drives.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.