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).
Stanford builds a heat shield just 10 atoms thick to protect electronic devices
19.08.2019 | Stanford University
Wearable sensors detect what's in your sweat
19.08.2019 | University of California - Berkeley
Experimental progress towards engineering quantized gauge fields coupled to ultracold matter promises a versatile platform to tackle problems ranging from condensed-matter to high-energy physics
The interaction between fields and matter is a recurring theme throughout physics. Classical cases such as the trajectories of one celestial body moving in the...
Soft robots have a distinct advantage over their rigid forebears: they can adapt to complex environments, handle fragile objects and interact safely with humans. Made from silicone, rubber or other stretchable polymers, they are ideal for use in rehabilitation exoskeletons and robotic clothing. Soft bio-inspired robots could one day be deployed to explore remote or dangerous environments.
Most soft robots are actuated by rigid, noisy pumps that push fluids into the machines' moving parts. Because they are connected to these bulky pumps by tubes,...
Researchers at TU Graz are working together with European partners on new possibilities of measuring vehicle emissions.
Today, air pollution is one of the biggest challenges facing European cities. As part of the Horizon 2020 research project CARES (City Air Remote Emission...
Over the next three years, researchers from the Vrije Universiteit Brussel, University of Cambridge, École Supérieure de Physique et de Chimie Industrielles de la ville de Paris (ESPCI-Paris) and Empa will be working together with the Dutch Polymer manufacturer SupraPolix on the next generation of robots: (soft) robots that ‘feel pain’ and heal themselves. The partners can count on 3 million Euro in support from the European Commission.
Soon robots will not only be found in factories and laboratories, but will be assisting us in our immediate environment. They will help us in the household, to...
Scientists at the University of Leeds have created a new form of gold which is just two atoms thick - the thinnest unsupported gold ever created.
The researchers measured the thickness of the gold to be 0.47 nanometres - that is one million times thinner than a human finger nail. The material is regarded...
16.08.2019 | Event News
14.08.2019 | Event News
12.08.2019 | Event News
20.08.2019 | Life Sciences
20.08.2019 | Physics and Astronomy
20.08.2019 | Power and Electrical Engineering