Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Computer models show device size matters

14.02.2014
Simulating the magnetic properties of nanostructures could help to design electronic memories with increased storage capacity

The ‘in-plane’ ferromagnetic-resonance response of a magnetic nanostructure changes with device size —shown here in the simulation results by the rapidly varying colors. The ‘out-of-plane’ response, on the other hand, is relatively constant.

© 2014 A*STAR Data Storage Institute

Scientists hope that patterning magnetic materials with nanometer-scale structures will help the development of non-volatile electronic memories with large storage capacities and no moving parts. So-called magnetoresistive random access memories are one example. But material properties at such tiny dimensions are not always the same as those of larger structures.

Kwaku Eason, Maria Sabino and their co-workers from the A*STAR Data Storage Institute, A*STAR National Metrology Centre and National University of Singapore have now modeled the changes in the characteristics of magnetic materials as devices are reduced in size to the nanoscale1.

The researchers focused their attention on modeling a powerful and widespread tool for characterizing magnetic materials called ferromagnetic resonance (FMR). FMR measures the absorption of microwave radiation by a thin sample. Knowing which microwave frequencies are absorbed the most can provide a number of key material properties. One such crucial property is the damping parameter, which is an indicator of how quickly a memory made from the magnetic material can store and release data.

The team employed a mathematical tool, known as the finite element method, to simulate a simple cylindrical nanodevice in all three dimensions. By calculating the energy levels of the device in an external magnetic field, the team could predict the FMR signal for devices of varying sizes.

The researchers compared their simulations to experimental data obtained on nanodisks made of a nickel–iron alloy, known as permalloy, and found good agreement for all device sizes. “Other groups have provided additional experimental results that further confirm the accuracy of our predictions,” says Eason.

The ability to predict the damping parameter of nanostructured magnetic materials is important because it is difficult to experimentally measure this property — partly because FMR signals from tiny targets are usually weak. Instead, researchers must study much larger devices and hope that the damping parameter is similar for nanostructures.

Recent experiments have conflicted on this point of scale. “One research group found from their experiments that device size does not matter in the damping measurement, while another group found that it does,” explains Eason. “We have resolved this dilemma: it turns out that they were both right.” Sabino adds: “The results were contradictory because of the different material properties.”

The simulations showed that the ‘in-plane’ magnetic properties are sensitive to the dimensions of the device, whereas the ‘out-of-plane’ properties are constant (see image).

“Contributing to a clear understanding of this effect is one of the most gratifying parts of this work,” says Eason.

The A*STAR-affiliated researchers contributing to this research are from the Singapore-based Data Storage Institute and the National Metrology Centre

Journal information

Eason, K., Sabino, M. P. R. G., Tran, M. & Liew, Y. F. Origins of magnetic damping measurement variations using ferromagnetic resonance for nano-sized devices. Applied Physics Letters 102, 232405 (2013).

A*STAR Research | Research asia research news
Further information:
http://www.a-star.edu.sg
http://www.researchsea.com
http://www.research.a-star.edu.sg/research/6881

More articles from Information Technology:

nachricht Software Provides a Clear Overview in Long Documents
24.07.2014 | Siemens AG

nachricht Wireless home automation systems reveal more than you would think about user behaviour
24.07.2014 | Universität des Saarlandes

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Anzeige

Anzeige

Event News

9th European Wood-Based Panel Symposium 2014 – meeting point for the wood-based material branch

24.07.2014 | Event News

“Lens on Life” - Artists and Scientists Explore Cell Divison

08.07.2014 | Event News

First International Conference on Consumer Research | ICCR 2014: Early bird deadline July 31, 2014

08.07.2014 | Event News

 
Latest News

Wildlife Conservation Society Helps Safeguard Belize’s Barrier Reef with Conservation Drones

28.07.2014 | Ecology, The Environment and Conservation

NIH scientists find 6 new genetic risk factors for Parkinson's

28.07.2014 | Life Sciences

Stanford team achieves 'holy grail' of battery design: A stable lithium anode

28.07.2014 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>