Giant Magneto Resistance(GMR)

Magneto Resistance(MR):

Hard Disk(HD):

When I was in 8th standard in 1998 computer era started mainly from MS DOS. In those days learning DOS was quite interesting but it became difficult while remembering all DOS commands. But still we did it by help command. Which has given the list of all necessary commands. In those days Pentium processor's were in big boom. We were unaware of all those things like Names, Speed of computer. Actually our computer class started with How to turn ON the computer and similarly the Turn OFF. But now things are changed. Person too, Computer Miss also.Main topic starts from the below paragraph.

When we heard the name technology,first thing will come to our mind is Computer. As we compare the size of computer in 1950's and now 2010. Lot's of change took place in Size, Speed and Storage of memory. Earlier they were in room size, now we can see notebook, laptop and palmtop's. Its because the change in semiconductor physics,which starts from Vacuum tubes to Microprocessor.

Today mainly I am concentrating on Hard Disk known name for all as it stores the songs, films, documents and necessary data. In scientific way, a hard disk stores information, such as music, in the form of microscopically small areas magnetized in different directions. The information is retrieved by a read-out head that scans the disk and registers the magnetic changes. The smaller and more compact the hard disk, the smaller and weaker the individual magnetic areas. More sensitive read-out heads are therefore required if information has to be packed more densely on a hard disk.

Many research people thinking to keep all universities library books in one hard disk. It will become difficult for them, when the hard disk is having capacity of 160GB. So in place of 160 GB they can have 160 TB[Tera Bytes](3TB is max in 2010 of 102mm in width) it might be possible for them. Of course they came with solution. That is Giant Magneto Resistance(GMR).

In 1988 the Frenchman Albert Fert and the German Peter Grünberg each independently discovered a totally new physical effect – Giant Magnetoresistance or GMR. Very weak magnetic changes give rise to major differences in electrical resistance in a GMR system. A system of this kind is the perfect tool for reading data from hard disks when information registered magnetically has to be converted to electric current. Soon researchers and engineers began work to enable use of the effect in read-out heads. In 1997 the first read-out head based on the GMR effect was launched and this soon became the standard technology. Even the most recent read-out techniques of today are further developments of GMR.


The year 2007 physics Nobel prize is awarded for the technology that is used to read data on hard disks. The technology that it has been possible to miniaturize hard disks so radically in recent years. Sensitive read-out heads are needed to be able to read data from the compact hard disks used in laptops and some music players, for instance.

If GMR is to work, structures consisting of layers that are only a few atoms thick have to be produced. For this reason GMR can also be considered one of the first real applications of the promising field of nanotechnology.

Now a days we are using 520GB hard disks, in that we can save at least one nation all university library books. Beyond our imagination.






To be Contd.............






mpshridhar








Credits:

www.research.ibm.com/research/gmr.html

Wikipedia for necessary information.

Google for Images.

Daily Science News Paper