From: Brian Ahern Macroscopic Au-Ag has no chance for RTSC …. However, nanoscale assemblies can result in ultra conduction. Zero resistance, but no Meisner Effect.
Well, shouldn’t we give the chaps from India the benefit of doubt…? OK … maybe not, but here is a hypothetical rationale for Au/Ag RTSC which fills in the blanks in Brian’s conclusion about nano-geometry. Although it is true that BCS theory successfully explains the lossless effect in terms of electron pairing theory (or did no at one time) and the formation of Cooper pairs is only possible in so-called “high-symmetry space” groups (but gold and silver are not in that group)... there is more to the story. Main overriding conclusion – Nothing NOTHING in the field of high temperature superconductivity is as simple as it first seems. There are exceptions to every rule and then exceptions to the exceptions. To wit, more recently (2014) superconductivity was seen in low-symmetry space groups (crystal structure which lacks spatial inversion symmetry). Gold compounds or alloys, specifically have shown the effect but not at room temperature. In particularly the National Institute for Materials Science (NIMS) synthesized a novel superconductor, SrAuSi3, which contains gold as a principal constituent. This only means that “symmetry space” is not simply a basic property of the elements involved, alone, but must also be considered in terms of a larger accumulation of atoms. https://phys.org/news/2014-04-discovery-gold-based-superconductor.html The reason that this could be relevant to the claim from India (if it is replicated) is then what is known as the Proximity effect or Holm-Meissner effect. The proximity effect describe the phenomena of a superconductor placed in contact with a highly conductive non-superconductor. Typically signs of superconductivity are observed in the normal metal. Holm and Meissner observed zero resistance in contacts where two superconducting metals are separated by a thin film of a non-superconducting material. This opens the possibility of slight oxidation in the silver nanoparticles which then is then transferred to the gold via an extreme proximity effect. OK – this is a stretch - and in a way it makes no one happy since impugns the Indian effort (unintended oxidation effect) but curiously no one has yet made a decent effort to find a way that this claim could work, as opposed to the knee-jerk reaction that it cannot work. If it does work this way (proximity effect), and especially if the nano-geometry benefits from the precision of advanced chip lithography (10 nm silver dots) then copper can probably be substituted for gold making the process economically viable as well as technically viable. Badhai, chaps… you may have opened the door. From: JonesBeene This is a well-written article about the apparent claim of room temperature superconductivity coming from India last year, https://thewire.in/the-sciences/iisc-room-temperature-superconductor-gold-silver-magnetic-susceptibility The problem is that there is still no replication and the upgraded paper is less than adequate, given the importance of the claim. Where are the replicators??? The interesting thing is that that only two elements are needed – gold and silver. Ubiquitous. Since these are readily available the critical detail then is getting the “nano” structure correct as clearly no alloy of gold and silver come close to RTSC by a factor of perhaps 10,000:1. There could be alternative ways to do this, including sputtering. For instance – we have a well developed nano-lithography industry in place in the computer chip industry. If RTSC is indeed possible with any combination of nanostructure using silver and gold – there is no better place to stage a replication attempt than in a chip fab or lab. Therefore the “gorilla in the closet” which everyone seems to be neglecting on this claim is IBM. They set the standard for both HTSC, having invented it, and for state of the art chips. They have a ready market. There is no greater fit for this tech on planet earth. Where art thou IBM ? Given the big picture, I cannot imagine that you have not taken notice… Jones
