Memristors – a revolutionary research field

By Shahar Kvatinsky | December 19, 2010

In 1971, Prof. Leon Chua from UC Berkeley published an article about the memristor, a fourth passive element in electronics (in addition to resistor, capacitor and inductor). Since Chua's article, memristors have become an exciting device that potentially can revolutionize the electronic industry. Chua predicted, only because of symmetry reasons, that there is a missing passive element, whose main characteristic is a relationship between flux (the total voltage being applied on it) and electric charge (the total current that had flown through it). Such a device actually acts as a resistor, but unlike the conventional resistor, its resistance is not constant, nor depends upon the temporary voltage being applied to it (as is the case for non-linear resistors).
The memristor's resistance depends on the total charge that had flown through it during the entire history of the device (or the total voltage being applied to it). It can be said that the resistance (or memristance) of this device is dependent on its history, or in other words – a memristos is a resistor that "remembers" its history.  The name "memristor" is derived from memory-resistor, a resistor with memory.

For example, applying 1 Volt of positive voltage for 1 second on a memristor (1 Volt·Sec), changes its resistance to lower resistance than its initial resistance, applying 2 Volts of negative voltage for half a second (also 1 Volt·Sec, but with negative value) will restore the memristor resistance to its initial value, while applying 1 Volt for half a second (in this case it is only 0.5 Volt·Sec, with negative value) will raise the memristor resistance to a lower value than its initial one.

Even upon the presentation of Chua's theoretical definition it was clear that this device has many potential applications.

The first and most obvious application is memory: a memristor-based memory has many advantages over conventional memories such as DRAM and SRAM. Not only that it is non-volatile (it remembers its resistance even when the machine is off), it also does not have any leakage current, which is a fundamental problem in nowadays memory technology.

Other applications can use the memristor as an additional device to transistors, and that way to overcome Moore's Law. It can be used for logic computations as well as for analog circuit applications (as another passive device).

Another potential application is using memristors in neuromorphic systems, because of the fact that memristors have similar behavior to synapses. These applications are widely described in this blog.

You have all probably heard, how in 2008 Hewlett-Packard published that they succeed to fabricate memristors. Since then, other memristors were "found" such as STT-MRAM, materials that are based on ionic drift, Spintronic memristors and organic memristors. On last April HP announced that on 2013 the first memristor-based memory will be available commercially.

As a graduate student in the Technion - Israel Institute of Technology, I was very enthusiastic when I first heard about memristors. Memristors have such a high potential to be used in many applications. Therefore I started thinking about additional applications, different from those mentioned above, and searching for improvements to existing applications.

Although the memristors research field is rising and developing in a fast pace, many papers are being published and a lot of information is being disseminated, it is hard to know which papers are interesting and innovative, and which are a duplicate of the previous work ("a review"). It is also hard to get information about research outside the primary research groups, such as HP's work.

Sometimes I find myself struggling to find a comprehensive and informative data base about this field.

When my advisor, Prof. Avinoam Kolodny, asked me whether there is any bibliographical list for articles about memristors, I decided to pick up the gauntlet and create one of my own.

I created a modest website, where I share my bibliographical list. This list contains many papers relevant to memristors, as well as other informative data for researchers who are interested in this field, such as conferences and useful links.

The website is still in its Beta version; changes will be made in order to make it handy and useful for researchers.

My vision is to make this website the primary information center for researchers in the memristor and memristive systems field.

You are all welcome to send me more information (interesting papers, data about conferences, links to useful websites etc.), to suggest improvements to the website, and to share it with your colleagues and whoever is interested in memristors.

I believe that this website can help all researchers in the memristor field and save us all precious time in the continuous seek for information.

Research in the area of memristors is developing, and I hope that my initiative will be helpful along this exciting journey.

The website address is:

http://webee.technion.ac.il/people/skva/memristor.htm

2 Responses to Memristors – a revolutionary research field

  1. Paul Adams says:

    The development of memristors is also exciting for neuroscientists, who study real synapses. Crucial questions facing neuroscientists are: (1) how fast can synapses change strength? (2) how large must the relevent voltages be, and how do they compare to the voltage that reads out the synapse state, but does not change the state? (3) how small can they be made (4) perhaps most crucially (but clearly linked to the first 3 questions), how closely can they be packed and at what crosstalk level?
    I would be interested to hear about all these issues for memristors, especially the last!

  2. ASHOK says:

    first of all thanks alot to Shahar Kvatinsky for his great work

    i have doubts on the concept of memristor

    1. How physical interaction between charge and the integral over the voltage.

    2.Why only nano scale,will it work in microns? what are the effects in micron scale?(i.e what happens if W & D increases?)

    3.why they have chosen only Tio2,are there any other insulating materials?

    4.How to bias memristor? will it drop any voltage like diode?

    5.for high frequencies the hysteresis loop becomes straight line then how can we use memristor in high frequencies?

    6. ” the memristor remembers the last resistance value it had ” if we apply voltage again the resistance might change then how can we get the last resistance value.

    if anyone knows please mail to “ashok_ict@yahoo.com”

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