News Article | November 1, 2016
Proceedings of the IEEE, the most highly cited general-interest journal in electrical engineering and computer science, announces the publication of a special issue covering advances in spintronics. “Over the last 10 years, there has been tremendous progress in commercially important areas of spintronics, including semiconductor-spintronic-based quantum computing and metal-based spintronics and sensors,” said Hideo Ohno, one of the guest editors for the special issue, and Director of Research Institute of Electrical Communication, Director of Center for Spintronics Integrated System, Director of Spintronics Research Network, all at Tohoku University. “While these areas will continue to be of great importance for further advancing the field, we expect to see emphasis shift to more of the applied aspects of spintronics." The special issue, which contains 12 papers, also highlights a number of technologies that may improve sensors and magnetic memories or develop into other devices such as three-terminal devices based on different aspects of spin-transfer torques (STT), spin-torque nano-oscillators, devices controlled by electric fields rather than currents, and devices based on magnetic skyrmions. Even further in the future, spintronics-based applications may be used in energy harvesting, bioinspired computing, and quantum technologies. “While the role of magnetic sensors will continue to remain important, magnetic random access memories (MRAMs) will play an increasing role both as standalone memory and embedded in a CMOS computer chip,” said Ohno. “We expect that STT-MRAM (Spin-Transfer Torque-MRAM) will also become a major storage technology because of its ability to scale well.” STT-MRAM leverages existing CMOS manufacturing techniques and can retain its data indefinitely, even when the power is lost or off. In addition to consuming low power and the low cost of flash memory, STT-MRAM is expected to play an important role in areas such as the Internet of Things (IoT), ultra low-power electronics, and high-performance computing (HPC). The other guest editors of the special issue include Mark D. Stiles, Fellow in the Center for Nanoscale Science and Technology (CNST) at National Institute of Standards and Technology (NIST), and Bernard Dieny, Chief Scientist at SPINTEC, a government laboratory he co-founded in Grenoble, France devoted to spin electronics. Other topics covered in the special issue include: To learn more about the special issue on Spintronics, please visit the Proceedings of the IEEE’s website, LinkedIn or Facebook page. About the Proceedings of the IEEE Founded in 1912 and first published in early 1913 (originally as Proceedings of the IRE), Proceedings of the IEEE is the most highly cited general-interest journal in electrical engineering and computer science. This journal provides the most in-depth tutorial and review coverage of the technical developments that shape our world, enlisting the help of guest editors and authors from the best research facilities, leading-edge corporations and universities around the world. For more information on Proceedings of the IEEE and the latest ideas and innovative technologies, visit http://www.ieee.org/proceedings, LinkedIn and Facebook. About IEEE IEEE, the world’s largest technical professional association, is dedicated to advancing technology for the benefit of humanity. Through its highly cited publications, conferences, technology standards, and professional and educational activities, IEEE is the trusted voice on a wide variety of areas ranging from aerospace systems, computers and telecommunications to biomedical engineering, electric power, and consumer electronics. Learn more at http://www.ieee.org.
Ohno H.,Tohoku University |
Stiles M.D.,U.S. National Institute of Standards and Technology |
Proceedings of the IEEE | Year: 2016
Provides an overview of the technical articles and features presented in this issue. © 1963-2012 IEEE.
Mikuszeit N.,SPINTEC |
Boulle O.,SPINTEC |
Buda-Prejbeanu L.,SPINTEC |
Mihai M.I.,SPINTEC |
2015 IEEE International Magnetics Conference, INTERMAG 2015 | Year: 2015
The discovery that the magnetization of a perpendicularly magnetized nanomagnet can be reversed by an in-plane current via spin orbit torque (SOT) has opened a new way to manipulate magnetization at the nanoscale1. This novel switching mechanism has led to a concept of non-volatile magnetic memory MRAM, namely the SOT-MRAM, which combines low power, fast switching, reliability and large endurance2. Although numerous experimental works were devoted to the study of magnetization switching by SOT, the mechanism of the magnetization reversal induced by SOT is poorly understood. Magnetization switching experiments were first interpreted in terms of a macrospin model3, but although a qualitative agreement could be achieved, the predicted switching current densities were very high compared to the experimental ones3-5. On the contrary, recent experimental works suggested that the magnetization during the switching is inhomogeneous and that switching occurs by domain nucleation followed by domain wall propagation6,7. However, the switching mechanisms were not elucidated. Here we present the results of micromagnetic simulations and analytical modelling which shed a new light on the magnetization reversal in the presence of SOT. We show that the Dzyaloshinskii-Moriya interaction (DMI) plays a key role in the reversal process by leading to a deterministic domain nucleation on the edge of the nanomagnet which triggers the reversal. A simple analytical model, taking into account the magnetization tilting on the edge due to the DMI, allows to calculate the switching current, which is the current for domain nucleation on the edge. Our model provides a much better agreement with experimental results compared to the macrospin approach. © 2015 IEEE.
Bandiera S.,SPINTEC |
Sousa R.R.,SPINTEC |
Rodmacq B.B.,SPINTEC |
IEEE Magnetics Letters | Year: 2011
An asymmetry in the interfacial anisotropies of Pt/Co and Co/Pt interfaces was observed in Pt/Co/Pt sputtered trilayers, the interfacial anisotropy arising from the bottom Pt/Co interface being significantly higher than that from the top Co/Pt one. Interdiffusion at the top interface is believed to be the main factor for this asymmetry. It dramatically decreases the anisotropy of the stack when the cobalt layer is thinner than 1 nm. By introducing ultrathin layers of materials immiscible with Co and acting as a diffusion barrier at the Co/Pt interface, the effective anisotropy can be doubled in this low Co thickness range. This is of great interest for spintronic devices, particularly for out-of-plane magnetized magnetoresistive random access memory structures that require high perpendicular magnetic anisotropy when their lateral dimensions are reduced below 45 nm. © 2010 IEEE.
Prejbeanu I.L.,Crocus Technology |
Bandiera S.,Crocus Technology |
Alvarez-Herault J.,Crocus Technology |
Sousa R.C.,Spintec |
And 2 more authors.
Journal of Physics D: Applied Physics | Year: 2013
This paper is focused on thermally assisted magnetic random access memories (TA-MRAMs). It explains how the heating produced by Joule dissipation around the tunnel barrier of magnetic tunnel junctions (MTJs) can be used advantageously to assist writing in MRAMs. The main idea is to apply a heating pulse to the junction simultaneously with a magnetic field (field-induced thermally assisted (TA) switching). Since the heating current also provides a spin-transfer torque (current-induced TA switching), the magnetic field lines can be removed to increase the storage density of TA-MRAMs. Ultimately, thermally induced anisotropy reorientation (TIAR)-assisted spin-transfer torque switching can be used in MTJs with perpendicular magnetic anisotropy to obtain ultimate downsize scalability with reduced power consumption. TA writing allows extending the downsize scalability of MRAMs as it does in hard disk drive technology, but it also allows introducing new functionalities particularly useful for security applications (Match-in-Place™ technology). © 2013 IOP Publishing Ltd.