Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Data storage: Making the switch

24.06.2013
Magnetic materials that change their properties when heated could pack more data on to hard drives
A ‘sandwich’ of three iron alloy layers could help to create computer hard drives that can store more data than ever before. Tiejun Zhou and co-workers at the A*STAR Data Storage Institute in Singapore expect that their development, based on a new technology called heat-assisted magnetic recording (HAMR), could boost the capacity of disks.

Conventional hard drives contain a tiny electromagnet — a write head — that hovers over a spinning disk coated with a ferromagnetic material. The electromagnet induces the magnetic field within small regions of the disk to point either up or down, encoding one bit of data.

Heat can jumble these magnetic bits and destroy the data. The latest disks use materials with a very large coercivity — a measure of how difficult they are to demagnetize. However, write heads must exert even greater magnetic fields to encode data in such materials. The balance between bit size, coercivity and the electromagnet's strength ultimately puts an upper limit on disk density of about 1 terabit per square inch.

In HAMR systems, each recording region is briefly heated above its Curie temperature, a point when magnetic coercivity drops significantly and a much smaller field can write the bit. Once the region cools, the coercivity rises and the bit locks into place.

Zhou’s team found a way to reduce both the writing temperature and the switching field in HAMR systems. The upper iron–platinum layer of the sandwich stores data bits; the lower iron–cobalt layer helps to channel the write-head’s magnetic field, enabling data writing; and the middle iron–rhodium layer acts as a switch between the two. The middle layer is antiferromagnetic at room temperature so blocks any magnetic coupling between the other layers. At about 350 kelvin, however, it becomes ferromagnetic, allowing the layers to couple.

Iron–platinum normally has a Curie temperature of about 750 kelvin, but that plummets when coupled to the iron–cobalt layer. Data can therefore be written to the iron–platinum layer once the iron–rhodium layer becomes ferromagnetic, at about 350 kelvin.

Coupling also reduces the coercivity of the iron–platinum layer, so a write head would need only to generate one-third of the usual magnetic field to encode a bit. “Theoretically, the bit can occupy a space as small as 100 square nanometers,” says Zhou. The team now plans to reduce the size of the nanocrystals in each data region of the iron–platinum layer, while maintaining its high coercivity.

The A*STAR-affiliated researchers contributing to this research are from the Data Storage Institute

A three-layer sandwich of magnetic materials could help to pack more data on to hard drives.

© Zoonar/Thinkstock

Journal information

Zhou, T. J., Cher, K., Hu, J. F., Yuan, Z. M. & Liu, B. The concept and fabrication of exchange switchable trilayer of FePt/FeRh/FeCo with reduced switching field. Journal of Applied Physics 111, 07C116 (2012).

A*STAR Research | Research asia research news
Further information:
http://www.research.a-star.edu.sg/research/6688
http://www.researchsea.com

More articles from Materials Sciences:

nachricht Serendipity uncovers borophene's potential
23.02.2017 | Northwestern University

nachricht Switched-on DNA
20.02.2017 | Arizona State University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

From rocks in Colorado, evidence of a 'chaotic solar system'

23.02.2017 | Physics and Astronomy

'Quartz' crystals at the Earth's core power its magnetic field

23.02.2017 | Earth Sciences

Antimicrobial substances identified in Komodo dragon blood

23.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>