An investigation into switching characteristics provides new criteria for achieving faster switching of magnetic memories.
Computer hard drives store data by writing magnetic information onto their surfaces. In the future, magnetic effects may also be used to improve active memory in computers, potentially eliminating the need to ‘boot up’ a computer. One way to achieve this is through a memory technology known as STT-MRAM that utilizes information stored in a pair of thin magnetic layers.
Pathways for the switching of a magnetic layer in an STT-MRAM device depend on the relative alignment of the two layers in the device.
Copyright : 2014 A*STAR Institute of High Performance Computing
By performing calculations, Chee Kwan Gan and colleagues from the A*STAR Institute of High Performance Computing have proposed ways to improve STT-MRAM memory through identifying design options for achieving faster switching speeds, and hence faster data write times .
In STT-MRAM devices, the relative orientation of the magnetic fields in the two thin layers determines the electrical resistance experienced by a current flowing through the device. If the magnetizations of both layers are aligned in the same direction, then the electrical resistance will be lower than when the layers have different magnetic alignments.
Switching the device between different magnetic states — which corresponds to writing information into the memory — is achieved by electrons whose magnetic property, the spin, is aligned in one direction. Collectively, these electrons are able to change the direction of the magnetization in one of the layers. The time it takes to switch the magnetic direction depends on several factors, including the initial relative orientation of the magnetic fields in the two layers. The magnetization of the switched layer can follow various complex paths during the switching process (see image).
In previous experiments, the switching process was found to depend on two parameters. Using their computational model, the researchers could focus on one parameter — the less-studied ‘field-like’ term — that accounts for the relative orientation of the magnetic fields in both layers. The strength of this term depends on various factors, such as the device geometry and the materials used.
The calculations by the researchers show that, for devices with a strong field-like term, there is greater potential to reduce switching times than for devices in which the field-like term is negligible. Gan explains that this discovery will assist the development of improved STT-MRAM devices. “Our findings will motivate experimentalists to fabricate devices with strong field-like terms,” says Gan.
Furthermore, a better understanding of the origin of the field-like term is needed, adds Gan. “Although the effect of the field-like term has been confirmed experimentally and investigated in this work through simulations, it is important to understand its physical origins in order to improve material design.”
1. Tiwari, R. K., Jhon, M. H., Ng, N., Srolovitz, D. J. & Gan, C. K. Current-induced switching of magnetic tunnel junctions: Effects of field-like spin-transfer torque, pinned-layer magnetization orientation, and temperature. Applied Physics Letters 104, 022413 (2014).
Scientists paint quantum electronics with beams of light
12.10.2015 | University of Chicago
TRIGA Mainz reaches world record of 20,000 pulses in 50 years
12.10.2015 | Johannes Gutenberg-Universität Mainz
Having a light touch can make a hefty difference in how well animals and robots move across challenging granular surfaces such as snow, sand and leaf litter. Research reported October 9 in the journal Bioinspiration & Biomimetics shows how the design of appendages – whether legs or wheels – affects the ability of both robots and animals to cross weak and flowing surfaces.
Using an air fluidized bed trackway filled with poppy seeds or glass spheres, researchers at the Georgia Institute of Technology systematically varied the...
Nondestructive material testing (NDT) is a fast and effective way to analyze the quality of a product during the manufacturing process. Because defective materials can lead to malfunctioning finished products, NDT is an essential quality assurance measure, especially in the manufacture of safety-critical components such as automotive B-pillars. NDT examines the quality without damaging the component or modifying the surface of the material. At this year's Blechexpo trade fair in Stuttgart, Fraunhofer IZFP will have an exhibit that demonstrates the nondestructive testing of high-strength automotive body parts using 3MA. The measurement results are available in a matter of seconds.
To minimize vehicle weight and fuel consumption while providing the highest level of crash safety, automotive bodies are reinforced with elements made from...
The MICADO camera, a first light instrument for the European Extremely Large Telescope (E-ELT), has entered a new phase in the project: by agreeing to a Memorandum of Understanding, the partners in Germany, France, the Netherlands, Austria, and Italy, have all confirmed their participation. Following this milestone, the project's transition into its preliminary design phase was approved at a kick-off meeting held in Vienna. Two weeks earlier, on September 18, the consortium and the European Southern Observatory (ESO), which is building the telescope, have signed the corresponding collaboration agreement.
As the first dedicated camera for the E-ELT, MICADO will equip the giant telescope with a capability for diffraction-limited imaging at near-infrared...
Self-driving cars will be on our streets in the foreseeable future. In Graz, research is currently dedicated to an innovative driver assistance system that takes over control if there is a danger of collision. It was nature that inspired Dr Manfred Hartbauer from the Institute of Zoology at the University of Graz: in dangerous traffic situations, migratory locusts react around ten times faster than humans. Working together with an interdisciplinary team, Hartbauer is investigating an affordable collision detector that is equipped with artificial locust eyes and can recognise potential crashes in time, during both day and night.
Inspired by insects
An interdisciplinary team of researchers has built the first prototype of a miniature particle accelerator that uses terahertz radiation instead of radio...
01.10.2015 | Event News
30.09.2015 | Event News
17.09.2015 | Event News
12.10.2015 | Press release
12.10.2015 | Press release
12.10.2015 | Physics and Astronomy