Breaking News
Comments
Newest First | Oldest First | Threaded View
<<   <   Page 2 / 3   >   >>
jaybus0
User Rank
CEO
Re: Good insight
jaybus0   10/4/2013 9:45:27 AM
NO RATINGS
Good queston. Although, according to Chua, there is a functional relationship between charge and flux (magnetic flux), which is the time integral of current and the time integral of voltage. The slope of this function is what he calls memristance. By this definition, a normal resistor is also a memristor. It just has a constant memristance (slope = 1). When memristance is constant, it is just defining Ohm's law.

These are theoretical electrical components. There will never be a real-world device, from HP or anyone else, that is purely a memristor, just as there will never be a device that is purely a capacitor or inductor. So, in that sense, if the application of current causes a change in resistance, then the term memristor could apply, just as we give the term resistor to a device even if it also ehibits some capacitance. 

PhyandEE
User Rank
Rookie
Re: Good insight
PhyandEE   10/2/2013 10:22:21 PM
NO RATINGS
It is interesting to find several more Arxiv papers on the discussion of memristor. I'm wondering whether they have tried to a journal, or just posted there. The memristor paper machine guys might need to answer the questions before their continuing using such a word, even it is really mysterious to them.

It is also interesting to find the pour of memristor neural networks papers from the biology guys.

PhyandEE
User Rank
Rookie
Re: Good insight
PhyandEE   10/2/2013 11:02:41 AM
NO RATINGS
A successful RRAM device, I think, should also be based on a structural change concept like Phase-change RAM, or from a charge storage concept such as flash. 

The state formed at a higher voltage should be kept at a lower voltage, with time. It is not a easy task, as described by HP, "any people can make".

PhyandEE
User Rank
Rookie
Re: Good insight
PhyandEE   10/2/2013 10:51:09 AM
NO RATINGS
I have just finished reading a Nature Nanotech paper by HP in 2008, another key paper by HP on memristor. 

The experiments there cannot even be regarded as a normal "design of experiments" concept, but such a paper can finally pass the peer-review process, and now with high citations. Any well-trained physicist will not accept the method and the superficial analysis described in this paper. 

It is really a shame in the scientific community. 

resistion
User Rank
CEO
Re: Good insight
resistion   10/2/2013 10:18:13 AM
NO RATINGS
Yes, it's a shame. But now, after awareness of RRAM, there will always be a temptation to reverse a failed insulator or conductor. Reliability will be redefined.

PhyandEE
User Rank
Rookie
Re: Good insight
PhyandEE   10/2/2013 9:41:21 AM
NO RATINGS
The resistive switching is a good concept for device development. Some very good results have been shown. There could be good future for ReRAM.

The "memristor", most of us even do not know what it is, should be kept as it was in 1970s, until a sound physical model has been shown. Any mathematicl modelling for a physical concept must be based on basic physical principles. 

In my opinion, the misleading "memristor" concept will not help but hurt the development of ReRAM devices. Before the HP works, there were already some excellent pioneer works on resistive switching. 

 

 

resistion
User Rank
CEO
Re: Good insight
resistion   10/2/2013 8:43:40 AM
NO RATINGS
I was told once that "memristor" in title helps get paper acceptance, especially those nano, science, nature, etc. journals.

PhyandEE
User Rank
Rookie
Re: Good insight
PhyandEE   10/2/2013 8:35:39 AM
NO RATINGS
One more...

What is the difference between "soft breakdown" and "hard breakdown"? Can I understand it like a "structural change" concept, but in different forms (or levels)? 

I read an early comment on resistive switching using the metal-insulator-transition concept. This is also based on a strucural change.

It seems nothing to do with the "memristor" concept in the HP paper.

 

PhyandEE
User Rank
Rookie
Re: Good insight
PhyandEE   10/2/2013 8:21:22 AM
NO RATINGS
Thanks - skeptic. There is much information in your reply.

I just read several papers on this. It is interesting to find that even the whole paper is talking about a phenomenon which can be explained by the known classical semiconductor physics principles, there is always a "memristor" word in the title. For example, the papers from one group from the University of Michigan, who recently announced the release of a chip based on such a concept (a so-called Crossbar comapny). 

"Memristor" looks like a new thing from "resistor, capacitor and inductor", but unfortunately I can find nothing new in these papers. They talked the same thing in the textbooks. I'm wondering whether they really understand what "memristor" means before they put this new word in their papers. 

 

 

A Sceptic
User Rank
Rookie
Re: Good insight
A Sceptic   10/2/2013 6:36:52 AM
NO RATINGS
What is called "resistance switching" is a sort of phenomena. Under certain conditions, "resistance switching" behavior can be brought about in various metal/insulator/metal structures after a soft-breakdown of the insulating material has occurred. Such effects could offer the potential for nonvolatile memory applications (ReRAM or RRAM). "Resistance switching" phenomena are well known since decades /1/ and are in no way related to the concept of "memristor/memristive" systems. Nevertheless, there is ongoing research because there are still a lot of questions with respect to the underlying physical mechanisms. Understanding into the probabilistic nature of the "resistance switching" operation is, for example, crucial to get grip on reliability issues of ReRAM devices.

What is called "memristor" is a sort of hypothetical concept. "Memristors" are conceptually defined by a unique set of characteristic mathematical state equations – based on the mathematical framework proposed by L. Chua /2/. Thus, solid state memory devices should only be labeled "memristors" if one is able to propose a reasonable physical model that satisfies these state equations.

Any scientific evidence that "memristors" might exist in physical reality is missing so far. HP's "memristor" model which was presented in 2008 in the NATURE paper "The missing memristor found" /3/ is, e.g., based on severe electrochemical misconceptions: one cannot derive the characteristic dynamic state equations of a "memristor" on base of HP's dopant drift model, i.e., no memory devices can operate in accordance with the model because the model is by itself in conflict with fundamentals of electrochemistry /4/. Thus, up to now nobody has invented or found a memory device which operates like a genuine nonvolatile "memristor".

Moreover, the nonvolatile "memristor" concept raises some severe questions when viewed from the perspective of non-equilibrium thermodynamics /4, 5/. Nonvolatile information storage requires the existence of energy barriers that separate distinct memory states from each other. "Memristors" whose resistance (memory) states depend only on the current (like the HP memristor) or voltage history would thus be unable to protect their memory states against unavoidable fluctuations and therefore permanently suffer information loss: the proposed hypothetical concept provides no physical mechanism enabling such systems to retain memory states after the applied current or voltage stress is removed. Such elements can therefore not exist, as they would always be susceptible to a so-called "stochastic catastrophe" /5/. It is therefore pointless to tinker with this concept in order to describe physical phenomena like "resistance switching" effects.

/1/ see, e.g.: N. Klein, "Switching and Breakdown in Films", Thin Solid Films, 7 (1971) (http://www.sciencedirect.com/science/article/pii/0040609071900678)

/2/ L. Chua, "Resistance switching memories are memristors", Appl. Phys. A, 102 (2011) (http://link.springer.com/article/10.1007/s00339-011-6264-9#)

/3/ D. B. Strukov, G. S. Snider, D. R. Stewart and R. S. Williams, "The missing memristor found", Nature, 453 (2008) (http://www.nature.com/nature/journal/v453/n7191/full/nature06932.html)

/4/ P. Meuffels and R. Soni, "Fundamental Issues and Problems in the Realization of Memristors", (2012) (http://arxiv.org/abs/1207.7319)

/5/ M. Di Ventra and Y. V. Pershin, "On the physical properties of memristive, memcapacitive, and meminductive systems", Nanotechnology, vol. 24, (2013) (http://iopscience.iop.org/0957-4484/24/25/255201)

<<   <   Page 2 / 3   >   >>


EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Max Maxfield

Aging Brass: Cow Poop vs. Horse Doo-Doo
Max Maxfield
46 comments
As you may recall, one of the things I want to do with the brass panels I'm using in my Inamorata Prognostication Engine is to make them look really old. Since everything is being mounted ...

EDN Staff

11 Summer Vacation Spots for Engineers
EDN Staff
18 comments
This collection of places from technology history, museums, and modern marvels is a roadmap for an engineering adventure that will take you around the world. Here are just a few spots ...

Glen Chenier

Engineers Solve Analog/Digital Problem, Invent Creative Expletives
Glen Chenier
15 comments
- An analog engineer and a digital engineer join forces, use their respective skills, and pull a few bunnies out of a hat to troubleshoot a system with which they are completely ...

Larry Desjardin

Engineers Should Study Finance: 5 Reasons Why
Larry Desjardin
45 comments
I'm a big proponent of engineers learning financial basics. Why? Because engineers are making decisions all the time, in multiple ways. Having a good financial understanding guides these ...

Flash Poll
Top Comments of the Week
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)