Memristor

and memristance

Transcript

1. Memristor a memory resistor
2. What is memristance? Memristance is a property of an electronic component. If charge flows in one direction through a circuit, the resistance of that component of the circuit will increase, and if charge flows in the opposite direction in the circuit, the resistance will decrease. If the flow of charge is stopped by turning off the applied voltage, the component will 'remember' the last resistance that it had, and when the flow of charge starts again the resistance of the circuit will be what it was when it was last active.
3. Why is memristance important? It turns out that memristance is becoming stronger as the feature sizes in circuits are getting smaller. At some point as we scale into the realm of nanoelectronics, it will be necessary to explicitly take account of memristance in our circuit models in order to simulate and design electronic circuits properly.
4. Have people seen memristance before? Yes, we are aware of over 100 published papers going back to at least the early 1960's in which researchers observed and reported unusual 'hysteresis' in their current- voltage plots of various devices and circuits based on many different types of materials and structures. In retrospect, we can understand that those researchers were actually seeing memristance, but they were apparently not aware of it.
5. What is a memristor? An ideal memristor is a passive two-terminal electronic device that is built to express only the property of memristance (just as a resistor expresses resistance and an inductor expresses inductance). However, in practice it may be difficult to build a 'pure memristor,' since a real device may also have a small amount of some other property, such as capacitance (just as any real inductor also has resistance).
6. A Memristor Is Like A Pipe ( Seriously)
7. What is an analogy for a memristor? A common analogy for a resistor is a pipe that carries water. The water itself is analogous to electrical charge, the pressure at the input of the pipe is similar to voltage, and the rate of flow of the water through the pipe is like electrical current. Just as with an electrical resistor, the flow of water through the pipe is faster if the pipe is shorter and/or it has a larger diameter. An analogy for a memristor is an interesting kind of pipe that expands or shrinks when water flows through it. If water flows through the pipe in one direction, the diameter of the pipe increases, thus enabling the water to flow faster. If water flows through the pipe in the opposite direction, the diameter of the pipe decreases, thus slowing down the flow of water. If the water pressure is turned off, the pipe will retain it most recent diameter until the water is turned back on. Thus, the pipe does not store water like a bucket (or a capacitor) – it remembers how much water flowed through it.
8. Very Fast and High Density
9. Two distinct advantages of memristors are that moving the vacancies between the adjacent levels can be done much faster than other known switching methods, and the cell density approaches that of hard disks. Theorized by Leon Chua in the early 1970s, and if commercially viable, memristors may replace flash memory and dynamic RAM (DRAM) in the future.
10. What types of applications could memristors have? For a type of non-volatile random access memory, or NVRAM. Such a memory would have very useful properties, in that it would not 'forget' the data that it stores when the power is turned off. We think that NVRAM made with the types of memristor materials that are currently being studied by many groups around the world could be a strong competitor to the flash memory market in about five years.
11. It Replaces RAM, Flash And Disk
12. What types of applications could memristors have? Another interesting application is as an 'artificial synapse' in a circuit designed for analog computation. Prof. Chua himself pointed out the connection between the properties of his proposed memristor and those of a synapse in his earliest papers, and he has performed a lot of research in the area of neural computing. We also think that this is a very interesting and potentially valuable research direction.
13. It Flattens The CPU Memory Hierarchy Divide With memristors you can decide if you want some block to be memory, a switching network, or logic. Williams claims that dynamically changing memristors between memory and logic operations constitutes a new computing paradigm enabling calculations to be performed in the same chips where data is stored, rather than in a specialized central processing unit.
14. 1808 Sir Humphry Davy is claimed to have performed the first experiments showing the effects of a memristor.
15. 2013 Senior lecturer Dr. Andy Thomas and his colleagues from Bielefeld University construct a memristor that is capable of learning. The group utilize memristors as key components in a blueprint for an artificial brain. The results are presented in the March print edition of the Journal of Physics published by the Institute of Physics in London
16. References • http://www.hpl.hp.com/news/2008/apr-jun/memristor_faq.html • http://en.wikipedia.org/wiki/Memristor • http://whatis.techtarget.com/definition/memristor • http://www.pcmag.com/encyclopedia_term/0,2542,t=memristor&i=59033,00.asp • http://highscalability.com/blog/2010/5/5/how-will-memristors-change-everything.html