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Author

Sorin Cotofana

Other affiliations: Nokia
Bio: Sorin Cotofana is an academic researcher from Delft University of Technology. The author has contributed to research in topics: Logic gate & CMOS. The author has an hindex of 24, co-authored 272 publications receiving 2679 citations. Previous affiliations of Sorin Cotofana include Nokia.


Papers
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Journal ArticleDOI
TL;DR: The Roadmap on Magnonics as mentioned in this paper is a collection of 22 sections written by leading experts in this field who review and discuss the current status but also present their vision of future perspectives.
Abstract: Magnonics is a rather young physics research field in nanomagnetism and nanoscience that addresses the use of spin waves (magnons) to transmit, store, and process information. After several papers and review articles published in the last decade, with a steadily increase in the number of citations, we are presenting the first Roadmap on Magnonics. This a collection of 22 sections written by leading experts in this field who review and discuss the current status but also present their vision of future perspectives. Today, the principal challenges in applied magnonics are the excitation of sub-100 nm wavelength magnons, their manipulation on the nanoscale and the creation of sub-micrometre devices using low-Gilbert damping magnetic materials and the interconnections to standard electronics. In this respect, magnonics offers lower energy consumption, easier integrability and compatibility with CMOS structure, reprogrammability, shorter wavelength, smaller device features, anisotropic properties, negative group velocity, non-reciprocity and efficient tunability by various external stimuli to name a few. Hence, despite being a young research field, magnonics has come a long way since its early inception. This Roadmap represents a milestone for future emerging research directions in magnonics and hopefully it will be followed by a series of articles on the same topic.

188 citations

Journal ArticleDOI
TL;DR: In this paper, the authors provide a tutorial overview of recent efforts to develop computing systems based on spin waves instead of charges and voltages, and discuss the current status and challenges to combine spin-wave gates and obtain circuits and ultimately computing systems, considering essential aspects such as gate interconnection, logic level restoration, input output consistency, and fan-out achievement.
Abstract: This paper provides a tutorial overview over recent vigorous efforts to develop computing systems based on spin waves instead of charges and voltages. Spin-wave computing can be considered a subfield of spintronics, which uses magnetic excitations for computation and memory applications. The Tutorial combines backgrounds in spin-wave and device physics as well as circuit engineering to create synergies between the physics and electrical engineering communities to advance the field toward practical spin-wave circuits. After an introduction to magnetic interactions and spin-wave physics, the basic aspects of spin-wave computing and individual spin-wave devices are reviewed. The focus is on spin-wave majority gates as they are the most prominently pursued device concept. Subsequently, we discuss the current status and the challenges to combine spin-wave gates and obtain circuits and ultimately computing systems, considering essential aspects such as gate interconnection, logic level restoration, input–output consistency, and fan-out achievement. We argue that spin-wave circuits need to be embedded in conventional complementary metal–oxide–semiconductor (CMOS) circuits to obtain complete functional hybrid computing systems. The state of the art of benchmarking such hybrid spin-wave–CMOS systems is reviewed, and the current challenges to realize such systems are discussed. The benchmark indicates that hybrid spin-wave–CMOS systems promise ultralow-power operation and may ultimately outperform conventional CMOS circuits in terms of the power-delay-area product. Current challenges to achieve this goal include low-power signal restoration in spin-wave circuits as well as efficient spin-wave transducers.

169 citations

Journal ArticleDOI
TL;DR: It is argued that spin-wave circuits need to be embedded in conventional CMOS circuits to obtain complete functional hybrid computing systems and the benchmark indicates that hybridspin-wave--CMOS systems promise ultralow-power operation and may ultimately outperform conventionalCMOS circuits in terms of the power-delay-area product.
Abstract: This paper provides a tutorial overview over recent vigorous efforts to develop computing systems based on spin waves instead of charges and voltages Spin-wave computing can be considered as a subfield of spintronics, which uses magnetic excitations for computation and memory applications The tutorial combines backgrounds in spin-wave and device physics as well as circuit engineering to create synergies between the physics and electrical engineering communities to advance the field towards practical spin-wave circuits After an introduction to magnetic interactions and spin-wave physics, all relevant basic aspects of spin-wave computing and individual spin-wave devices are reviewed The focus is on spin-wave majority gates as they are the most prominently pursued device concept Subsequently, we discuss the current status and the challenges to combine spin-wave gates and obtain circuits and ultimately computing systems, considering essential aspects such as gate interconnection, logic level restoration, input-output consistency, and fan-out achievement We argue that spin-wave circuits need to be embedded in conventional CMOS circuits to obtain complete functional hybrid computing systems The state of the art of benchmarking such hybrid spin-wave--CMOS systems is reviewed and the current challenges to realize such systems are discussed The benchmark indicates that hybrid spin-wave--CMOS systems promise ultralow-power operation and may ultimately outperform conventional CMOS circuits in terms of the power-delay-area product Current challenges to achieve this goal include low-power signal restoration in spin-wave circuits as well as efficient spin-wave transducers

115 citations

Proceedings ArticleDOI
19 Apr 2001
TL;DR: A novel design of an n-input linear threshold gate which can accommodate both positive and negative weights and built-in signal amplification, using 1 tunnel junction and n+2 true capacitors is introduced.
Abstract: In this paper we focus on the design of threshold logic functions in Single Electron Tunneling (SET) technology, using the tunnel junction's specific behavior i.e., the ability to control the transport of individual electrons. We introduce a novel design of an n-input linear threshold gate which can accommodate both positive and negative weights and built-in signal amplification, using 1 tunnel junction and n+2 true capacitors. As an example we present a 4-input threshold gate with both positive and negative weights.

106 citations

Proceedings ArticleDOI
10 Dec 2002
TL;DR: A new hardware unit that performs a 16/spl times/1 SAD operation in field-programmable gate arrays (FPGA), because it provides increased flexibility, sufficient performance, and faster design times.
Abstract: In this paper we propose a new hardware unit that performs a 16/spl times/1 SAD operation. The hardware unit is intended to augment a general-purpose core. Further we show that the 16/spl times/1 SAD implementation used can be easily extended to perform the 16/spl times/16 SAD operation, which is commonly used in many multimedia standards, including MPEG-1 and MPEG-2. We have chosen to implement the 16/spl times/1 SAD operation in field-programmable gate arrays (FPGA), because it provides increased flexibility, sufficient performance, and faster design times. We performed simulations to validate the functionality of the 16/spl times/1 SAD implementation using the MAX+plus 11 (version 9.23 BASELINE) software from Altera and synthesis using the FPGA Express (version 3.4) software from Synopsis. Targeting the Altera's FLEX20KE family, synthesis of our 16/spl times/1 SAD unit produced the following results for area and clock frequency: 1699 look-up tables (LUT) and 197 MHz, respectively.

87 citations


Cited by
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Journal Article
TL;DR: Electrical writing is combined in solid-state memory with electrical readout and the stored magnetic state is insensitive to and produces no external magnetic field perturbations, which illustrates the unique merits of antiferromagnets for spintronics.
Abstract: Manipulating a stubborn magnet Spintronics is an alternative to conventional electronics, based on using the electron's spin rather than its charge. Spintronic devices, such as magnetic memory, have traditionally used ferromagnetic materials to encode the 1's and 0's of the binary code. A weakness of this approach—that strong magnetic fields can erase the encoded information—could be avoided by using antiferromagnets instead of ferromagnets. But manipulating the magnetic ordering of antiferromagnets is tricky. Now, Wadley et al. have found a way (see the Perspective by Marrows). Running currents along specific directions in the thin films of the antiferromagnetic compound CuMnAs reoriented the magnetic domains in the material. Science, this issue p. 587; see also p. 558 Transport and optical measurements are used to demonstrate the switching of domains in the antiferromagnetic compound CuMnAs. [Also see Perspective by Marrows] Antiferromagnets are hard to control by external magnetic fields because of the alternating directions of magnetic moments on individual atoms and the resulting zero net magnetization. However, relativistic quantum mechanics allows for generating current-induced internal fields whose sign alternates with the periodicity of the antiferromagnetic lattice. Using these fields, which couple strongly to the antiferromagnetic order, we demonstrate room-temperature electrical switching between stable configurations in antiferromagnetic CuMnAs thin-film devices by applied current with magnitudes of order 106 ampere per square centimeter. Electrical writing is combined in our solid-state memory with electrical readout and the stored magnetic state is insensitive to and produces no external magnetic field perturbations, which illustrates the unique merits of antiferromagnets for spintronics.

756 citations

Proceedings Article
01 Jan 2009
TL;DR: This paper summarizes recent energy harvesting results and their power management circuits.
Abstract: More than a decade of research in the field of thermal, motion, vibration and electromagnetic radiation energy harvesting has yielded increasing power output and smaller embodiments. Power management circuits for rectification and DC-DC conversion are becoming able to efficiently convert the power from these energy harvesters. This paper summarizes recent energy harvesting results and their power management circuits.

711 citations

01 Jan 2017
TL;DR: The 2017 roadmap of terahertz frequency electromagnetic radiation (100 GHz-30 THz) as mentioned in this paper provides a snapshot of the present state of THz science and technology in 2017, and provides an opinion on the challenges and opportunities that the future holds.
Abstract: Science and technologies based on terahertz frequency electromagnetic radiation (100 GHz–30 THz) have developed rapidly over the last 30 years. For most of the 20th Century, terahertz radiation, then referred to as sub-millimeter wave or far-infrared radiation, was mainly utilized by astronomers and some spectroscopists. Following the development of laser based terahertz time-domain spectroscopy in the 1980s and 1990s the field of THz science and technology expanded rapidly, to the extent that it now touches many areas from fundamental science to 'real world' applications. For example THz radiation is being used to optimize materials for new solar cells, and may also be a key technology for the next generation of airport security scanners. While the field was emerging it was possible to keep track of all new developments, however now the field has grown so much that it is increasingly difficult to follow the diverse range of new discoveries and applications that are appearing. At this point in time, when the field of THz science and technology is moving from an emerging to a more established and interdisciplinary field, it is apt to present a roadmap to help identify the breadth and future directions of the field. The aim of this roadmap is to present a snapshot of the present state of THz science and technology in 2017, and provide an opinion on the challenges and opportunities that the future holds. To be able to achieve this aim, we have invited a group of international experts to write 18 sections that cover most of the key areas of THz science and technology. We hope that The 2017 Roadmap on THz science and technology will prove to be a useful resource by providing a wide ranging introduction to the capabilities of THz radiation for those outside or just entering the field as well as providing perspective and breadth for those who are well established. We also feel that this review should serve as a useful guide for government and funding agencies.

690 citations