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Fujitsu announces technology for future hard drive capacity expansion

Fujitsu of America announced another advancement in its research of magnetic recording. Using patterned media technology, Fujitsu was able to achieve a one-dimensional array nanohole pattern with a 25 nanometer pitch. This process could one day enable one terabit per square inch recording on HDDs. Fujitsu also revealed a new development involving perpendicular magnetic recording read/write operation on random patterned media. With this technology, the soft underlayer is used as the PMR media, another important milestone.

A density of one terabit per square inch is about five times greater than the current drive technology on the market. Applying a one terabit areal density figure to today’s drive sizes would give us 3.5” drives capable of storing 5TB or 2.5” notebook drives holding 1.5TB.

Fujitsu first announced innovations with patterned media recording in June 2005. At that time, advancements were made with the introduction of a process to pre-pit aluminum media, resulting in nanoholes with an extremely dense and ordered structure. In addition, a technique called land/groove texturing allowed for the creation of discrete tracks in which the nanoholes could be formed. This progress in patterned media has enabled the development of high capacity hard disk drives, especially in smaller form factors.

This progress in patterned media recording closely follows the November 2006 Fujitsu announcement regarding the optical element being developed for thermal assisted recording, another promising advancement for future capacity increases.



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By patentman on 1/24/2007 12:28:51 PM , Rating: 2
Nanodot media has been around for a while, even will before 2005.

Proof: See http://www.newscientist.com/article.ns?id=dn6362

I posted the following comment regaridng the linked article on the Anandtech forums under the name klaviernista at around the same time the article was posted (typos corrected):

"I examine patent applications for magentic media at the patent and trademark office. The problem you are describing has been around for a long time, as has so called "nanodot" media. This problem is called "intergranular exchange coupling" and contributes to increased noise in high density magnetic media.

This problem arose as a result of the industry striving towards increased recording density. One way to get increased recording density is to reduce the size of the grains in magnetic layer (Basically, 1 grain=1 bit, so more grains = more bits per square inch). The problem with this is that as you reduce grain size, the coercivity (basically the strength by which a magnetic domain is held in a fixed direction) decreases. In other words, the orientation of each domain in each bit becomes more susceptible to being influenced by external magnetic fields. Well, as each grain is magnetic and the coercivity of each grain is low at small grain sizes, the magnetic field of each grain impacts the orientation of the domain in each surrounding grain. As a result, the noise of the media is increased.

Industry has come up with a variety of ways to combat this problem. the most common way to prevent or reduce this type of coupling is to introduce Cr into the magnetic layer. Cr only has a certain solubilty in the crystalline lattice of a Co alloy (Co is the most common element used for the magentic layers in magentic media). When the CoCr magnetic layer is formed, it is first deposited (via sputtering or cvd) and then annealed. As a result of the annealing step, excess Cr segregates from within the crystalline grain into the area between adjacent grains (called the grain boundary). By controlling the amount of Cr which segregates, the spacing between grains is controlled. As you probably know, magnetic field intensity decreases as the distance from its origin increases. Thus, the influence of each grain's magnetic field on surrounding grains is substantially reduced by the introduction of Cr into the grain boundary. In addition, non-magentic oxides such as SiO2 and TiO2 have also been used to segregate grains.

So, with nanodot media and quantum dot media, it is likely that some form of segregant will be utilized to separate each dot, or the dots themselves will be spaced apart when they are deposited so as to minimize this type of grain coupling. Many quantum dot media are formed by self assembly methods, so control over spacing between each dot can usually be controlled realtively easily."

later in the same thread, I posted the following comment:

"Oh, and the article states something to the effect of: these researchers have created 5nm nickel dots, which are about 10 times smaller then those previously produced. It shouold read "those previously produced, by them." I personally worked on a project at the Naval Research Laboratory a number of years (note, this project took place from 1996-1999) back where I used a reverse micelle synthesis technique to fabricate spherical 3 nm Iron Oxide (superparamagnetic) and 11nm FePt (ferromagnetic) nanoparticles. Further, the use of the reverse micelle technique to create magnetic nanoparticles on the scale asserted by these researchers has been known since the early 90's, and the potential use of these particles as memory has been around since the mid 90's as well. So to me there is nothing really new about wehat these guys have done.

I'm not trying ot sound arrogant, I'm just letting you know that this isn't really new is all. Still interesting tech though. "

FOr other interesting articles about nanodots and their potentioal use in memory, see the patent and non-patent literature of Dr. Everett Carpenter, who to my knowledge is still a researcher at the Naval Research Lab.




By dice1111 on 1/24/2007 12:48:00 PM , Rating: 2
No where in the article does it says it's new Nanodot tech, just a new application for Fujitsu as a company to increase density.

Thank you for the exausting and irrelivent post.


By patentman on 1/24/2007 12:53:54 PM , Rating: 2
Read the title of the article: "Fujitsu Makes Advancement in Hard Drive Density"

Now read the title again.... Fujitsu makes "ADVANCEMENT." My post above indicates that did no such thing. All Fujitsu did was announce that they have a potential commercial product, yet the article makes it sound like they invented nanodot media. This is far from true.

"In addition, a technique called land/groove texturing allowed for the creation of discrete tracks in which the nanoholes could be formed"

Land groove texturing is EXTREMELY old technology, yet the article implies that it is the bees knees of nanodot media. Hell, land/groove is based on the exact same technology as the manufacturing techniques for optical CD's.

Thank you for your ignorant and uneducated post.


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