Thanks for link
Here is some Christmas holiday reading. HP's claim that RRAM, PCM, and MRAM are all memristor technologies is bullshit, the memristor is not a fourth fundamental circuit element, HP didn't find it, and its developing memristor product is a not a memristor - really. The flame from Blaise So says ex-USPTO patent examiner and …
If the oxygen vacancy leads to formation of unpaired electron spins, then there would be an associated magnetic flux. Since there are many materials where the resistance is dependent on magnetic flux, the presence or absence of unpaired spins could have an effect on resistance.
Chua's postulated interaction of charge and flux doesn't make too much sense in classical electrodynamics, but does make more sense at the quantum level.
I was going to give thanks to Mr Mouttet for using up 15 minutes of my life that I wouldn't get back any time soon, but in fact, I thoroughly enjoyed the discussion within the article, and indeed in the above comments. Didn't understand hardly any of it, A-S Level Electronics was oh-so-very long ago, but I still enjoyed it all.
Here's hoping it's a sign for 2012, more top drawer boffinry all round please, no more stooping to the lowest common denominator.
"as represented by Ohm's law; i=v/r"
Not a bad article, but it clearly shows that it has been written by someone with very little understanding of electronics and math. FYI: the international designator for voltage is 'U' (capital), not 'v'. Resistance is 'R' (again capital) and not 'r', and current is 'I (again capital); and not 'i'. So Ohm's law is 'I=U/R'
'i' is an imaginary number (i=SQRT(-1)) and becomes extremely important when looking at AC, capacities and impedances and the shifted relation between U and I, expressed through complex math.
Errors like this would have brought me a slap on my head in basic electronics training, and certainly shouldn't happen in an article that wants to discuss advanced electronics.
but I thought engineers used j as sqrt(-1) and mathematicians used i, and that mathematicians are wrong :)
Also, our lecturers used I for DC and i for AC. I can't remember if they generally used U for potential difference (though they nearly always talked about pd instead of voltage in diagrams)
Granted I got my lowest marks in my first electric circuits module and steered myself to computing modules, but I did slightly better in the communications and signals modules later on when there were fewer nasty matrices around (though less said about my comprehension of compound trig the better)
> the international designator for voltage is 'U' (capital)
Not when I was at University, it wasn't.
Do you have a reference for your claim? I remember a French attempt to force us all into using U rather than V, but I'm pretty sure it didn't get adopted - not universally, at any rate.
> 'i' is an imaginary number
In mathematics, that is so. In electronics, it is frequently used for AC current. The clash between meanings is resolved by using the term "j" for the imaginary unit.
> Errors like this would have brought me a slap on my head
You might yet get one...
It seems to me the merits of this article are dubious:
Journalist writes article
Someone takes issue ('flames' allegedly)
Journalist writes rebuttal
The journalist should not have written the rebuttal. A knowledgeable 3rd party should have. As it stands, the rebuttal might represent a fine analysis but we can never know how objective the journalist has been drafting the rebuttal.
In particular the journalist has sided with Williams (which might be the correct position). However as a dispassionate reader the basic criticism (that the goal posts have been moved whether by Chua or Williams) doesn't really seem to have been addressed. Rather the journalist has just disagreed with the criticism (no surprise there). So we 3rd parties are no wiser.
Blaise Mouttet has sent in the following email, which is reproduced here:
HAPPY NEW YEAR!
Regarding your recent article on the "memristor brouhaha":
Stan Williams is dead wrong that phase change memory (and other unipolar memory types) can be accurately considered a memristor (even given the recently revised 2011 definition which is arguably fraudulent in and of itself). Neither Stan Williams nor Leon Chua have any expertise in phase change memory (or various of the other memory types Williams claims to be "memristors"). No one as far as I know has provided a correct proof or reasonable model showing that phase change memory can be accurately modeled as a memristor or as a 1st order memristive system. It is irresponsible for Stan Williams to be spreading this type of misinformation for the consumption of the popular press unless such a proof is first produced and well vetted in the scientific literature. I believe that Williams is doing this for business reasons that have nothing to do with correct science. This is very dangerous if it is allowed to continue unchecked.
I am cc'ing David Wright who has a great deal of expertise in modeling phase change memory materials and who has published at least one paper I am aware of peripherally related to the memristor concept.
I am also cc'ing Dalibor Biolek who was one of the first researchers to create SPICE models for memristive systems and who recently published an important paper distinguishing between the pinched hysteresis loops of bipolar (TYPE 1, Fig.1a) and unipolar (TYPE 2, Fig. 1b) memory.
In the 1976 paper by Chua and Kang an example of an impossible Lissajous curve for memristive one-ports was given based on property 4 of memristive systems (see Fig. 5b). The characteristic of this curve is similar to that found due to the voltage snap back in phase change memory which David Wright or any other researcher in phase change memory can confirm. Thus either Chua and Williams are ignoring this property or (more likely) have too little knowledge of phase change memory to realize that a claim that phase change memory is a memristor is easily provable to be scientifically false.
The more recent article by Dalibor gets more directly to the point by noting in the conclusion that memristance-charge or memductance-flux relationships cannot generate pinched hysteresis loops of type-II (which are typically associated with unipolar switching found in phase change memory).
Willliams is making false claims about the memristor either out of his own ignorance or deliberate attempt at fraud to advance HP's business agenda (at the cost of legitimate companies developing ReRAM such as Sharp, Samsung, and Unity Semiconductor). This should not be allowed and serves only to create confusion in the public.
Given the above information Williams should at minimum withdraw his allegation that phase change memory is a memristor and apologize.
I am currently preparing an article which I will be posting on wordpress in a few days going into more detail about why various of the arguments made by Williams in his rebuttal are completely bogus.
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