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Multiferroic nanomagnetic logic: Hybrid spintronics-straintronic paradigm for ultra-low energy computing
| Content Provider | Semantic Scholar |
|---|---|
| Author | Fashami, Mohammad Salehi |
| Copyright Year | 2014 |
| Abstract | MULTIFERROIC NANOMAGNETIC LOGIC: HYBRID SPINTRONICSSTRAINTRONIC PARADIGM FOR ULTRA-LOW ENERGY COMPUTING By Mohammad Salehi Fashami A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University. Virginia Commonwealth University, 2014 Director: Jayasimha Atulasimh, PhD. Associate Professor, Department of Mechanical and Nuclear Engineering School of Engineering Excessive energy dissipation in CMOS devices during switching is the primary threat to continued downscaling of computing devices in accordance with Moore’s law. In the quest for alternatives to traditional transistor based electronics, nanomagnet-based computing [1, 2] is emerging as an attractive alternative since: (i) nanomagnets are intrinsically more energy-efficient than transistors due to the correlated switching of spins [3], and (ii) unlike transistors, magnets have no leakage and hence have no standby power dissipation. However, large energy dissipation in the clocking circuit appears to be a barrier to the realization of ultra low power logic devices with such nanomagnets. To alleviate this issue, we propose the use of a hybrid spintronics-straintronics or straintronic nanomagnetic logic (SML) paradigm. This uses a piezoelectric layer elastically coupled to an elliptically shaped magnetostrictive nanomagnetic layer for both logic [4-6] and memory [7-8] and other information processing [9-10] applications that could potentially be 2-3 orders of magnitude more energy efficient than current CMOS based devices. This dissertation focuses on studying the feasibility, performance and reliability of such nanomagnetic logic circuits by simulating the nanoscale magnetization dynamics of dipole coupled nanomagnets clocked by stress. Specifically, the topics addressed are: 1. Theoretical study of multiferroic nanomagnetic arrays laid out in specific geometric patterns to implement a “logic wire” for unidirectional information propagation and a universal logic gate [4-6]. 2. Monte Carlo simulations of the magnetization trajectories in a simple system of dipole coupled nanomagnets and NAND gate described by the Landau-LifshitzGilbert (LLG) equations simulated in the presence of random thermal noise to understand the dynamics switching error [11, 12] in such devices. 3. Arriving at a lower bound for energy dissipation as a function of switching error [13] for a practical nanomagnetic logic scheme. 4. Clocking of nanomagnetic logic with surface acoustic waves (SAW) to drastically decrease the lithographic burden needed to contact each multiferroic nanomagnet while maintaining pipelined information processing. 5. Nanomagnets with four (or higher states) implemented with shape engineering. Two types of magnet that encode four states: (i) diamond, and (ii) concave nanomagnets are studied for coherence of the switching process. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://scholarscompass.vcu.edu/cgi/viewcontent.cgi?article=4556&context=etd&httpsredir=1&referer= |
| Alternate Webpage(s) | http://scholarscompass.vcu.edu/cgi/viewcontent.cgi?article=4556&context=etd |
| Alternate Webpage(s) | https://scholarscompass.vcu.edu/cgi/viewcontent.cgi?article=4556&context=etd |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
