The disk drive in a computer works by using a magnetic field to change the physical properties of a tiny volume of a magnetically susceptible material. Current research aims to develop novel materials and technologies that can maximize storage capacity by focusing data into the smallest possible volume.
Now, Zhanhong Cen and co-workers at the A*STAR Data Storage Institute in Singapore have experimentally and theoretically investigated the properties of iron-Cplatinum (FePt) nanocrystals for use in ultrahigh-density magnetic recording media. They show that, as well as having the appropriate magnetic characteristics, the optical response of FePt is suitable for high-performance data-storage applications and that the use of pulses of laser light improves the magnetic recording process1.
"Decreasing the size of magnetic particles makes the magnetic information become thermally unstable due to an effect called superparamagnetism," explains Cen. "FePt nanoparticles are very promising, because for these nanoparticles, superparamagnetism is suppressed at room temperature."
But FePt nanoparticles also have a drawback - the magnetic field required for writing data is much higher than that produced by present disk drives. While the magnetic-field intensity necessary for a change of state could potentially be reduced by locally heating the material with a pulse of light - a process called heat-assisted magnetic recording, little was known about the optical response of FePt until now.
Cen and the team created thin-film samples using a process known as sputtering, which involves firing a beam of particles at a FePt alloy to release iron and platinum atoms. The atoms land on a glass substrate covered with a layer of magnesium oxide where they form crystals. The team sputtered carbon at the same time to form a single layer of FePt nanocrystals 15 nanometers in diameter and 9.1 nanometers tall embedded in a film of carbon.
For comparison, the team also created a nanocrystal sample without carbon and probed the refractive index and absorption of the two samples with both visible and near-infrared light. The researchers used these values in a computer model to simulate the performance of the material in a heat-assisted magnetic recording device. The sample doped with carbon came out on top.
"Our simulations show that introducing carbon into a FePt nanocomposite can improve optical performance," says Cen. "Ultimately, a FePt-carbon recording medium will perform better than current storage options, because it will use a smaller optical spot on the recording media and enable more energy-efficient writing and reading of data."
The A*STAR-affiliated researchers contributing to this research are from the Data Storage Institute
Cen, Z. H., Xu, B. X., Hu, J. F., Li, J. M., Cher, K. M. et al. Optical property study of FePt-C nanocomposite thin film for heat-assisted magnetic recording. Optics Express 21, 9906¨C9914 (2013).
Magnetic fields provide a new way to communicate wirelessly
01.09.2015 | University of California - San Diego
'Magic' sphere for information transfer
24.08.2015 | Lomonosov Moscow State University
In a survey of NASA's Hubble Space Telescope images of 2,753 young, blue star clusters in the neighboring Andromeda galaxy (M31), astronomers have found that M31 and our own galaxy have a similar percentage of newborn stars based on mass.
By nailing down what percentage of stars have a particular mass within a cluster, or the Initial Mass Function (IMF), scientists can better interpret the light...
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE have developed a highly compact and efficient inverter for use in uninterruptible power...
China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from University of Arizona geoscientists. The study is the first to explain how the steep-fronted plateau formed.
China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from...
The leaves of the lotus flower, and other natural surfaces that repel water and dirt, have been the model for many types of engineered liquid-repelling surfaces. As slippery as these surfaces are, however, tiny water droplets still stick to them. Now, Penn State researchers have developed nano/micro-textured, highly slippery surfaces able to outperform these naturally inspired coatings, particularly when the water is a vapor or tiny droplets.
Enhancing the mobility of liquid droplets on rough surfaces could improve condensation heat transfer for power-plant heat exchangers, create more efficient...
Longer, more severe, and hotter droughts and a myriad of other threats, including diseases and more extensive and severe wildfires, are threatening to transform some of the world's temperate forests, a new study published in Science has found. Without informed management, some forests could convert to shrublands or grasslands within the coming decades.
"While we have been trying to manage for resilience of 20th century conditions, we realize now that we must prepare for transformations and attempt to ease...
03.09.2015 | Event News
20.08.2015 | Event News
20.08.2015 | Event News
04.09.2015 | Power and Electrical Engineering
04.09.2015 | Machine Engineering
04.09.2015 | Materials Sciences