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).
Interstellar seeds could create oases of life
28.08.2015 | Harvard-Smithsonian Center for Astrophysics
Draw out of the predicted interatomic force
28.08.2015 | Hiroshima University
A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space Telescope.
The discovery of two supermassive black holes--one larger one and a second, smaller one--are evidence of a binary black hole and suggests that supermassive...
A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal areas in southern Italy and Greece. The study is published today (27 August) in Ocean Science, an open access journal of the European Geosciences Union (EGU).
Though not as frequent as in the Pacific and Indian oceans, tsunamis also occur in the Mediterranean, mainly due to earthquakes generated when the African...
In mountainous regions earthquakes often cause strong landslides, which can be exacerbated by heavy rain. However, after an initial increase, the frequency of these mass wasting events, often enormous and dangerous, declines, in fact independently of meteorological events and aftershocks.
These new findings are presented by a German-Franco-Japanese team of geoscientists in the current issue of the journal Geology, under the lead of the GFZ...
Bacteria do not cease to amaze us with their survival strategies. A research team from the University of Basel's Biozentrum has now discovered how bacteria enter a sleep mode using a so-called FIC toxin. In the current issue of “Cell Reports”, the scientists describe the mechanism of action and also explain why their discovery provides new insights into the evolution of pathogens.
For many poisons there are antidotes which neutralize their toxic effect. Toxin-antitoxin systems in bacteria work in a similar manner: As long as a cell...
It comes when called, bringing care utensils with it and recording how they are used: Fraunhofer IPA is developing an intelligent care cart that provides care staff with physical and informational support in their day-to-day work. The scientists at Fraunhofer IPA have now completed a first prototype. In doing so, they are continuing in their efforts to improve working conditions in the care sector and are developing solutions designed to address the challenges of demographic change.
Technical assistance systems can improve the difficult working conditions in residential nursing homes and hospitals by helping the staff in their work and...
20.08.2015 | Event News
20.08.2015 | Event News
19.08.2015 | Event News
28.08.2015 | Physics and Astronomy
28.08.2015 | Health and Medicine
28.08.2015 | Life Sciences