Superconductors Definition and 147 Threads

What would happen to cosmic rays if you put superconductor material on the hull of a spacecraft ? Would the flux trapping effect trap the cosmic rays? Could the superconductor protect the spacecraft from cosmic rays? Could it be possible to create a superconductor magnet that can produce a...

According to Prof Egor Babaev and others, it seems possible to have knotted solitons in certain superconductors. He has had numerous articles published in Physical Review and Nature. The most understandable one I've found is Hidden symmetry and knot solitons in a charged two-condensate Bose...

So I'm a little confused about the Meissner Effect. If we have both a perfect conductor and a superconductor (both above Tc) and place them in a magnetic field and lower their temperatures so they exhibit their respective properties, the magnetic field inside the perfect conductor persists...

I apologize beforehand for my lack of experience in searching through scientific articles or journals. But I was reading an article about super conductors, and then the question popped into my head. Has anyone heard of an experiment that tested various known superconductors under different...

Hello. I am reading about Flux pinning and I have read that only type-II superconductors can be used for that because there is no magnetic field in type-I superconductors (or rather they cannot be penetrated). If so, how can type-I superconducotrs still have a critical magnetic field strength...

So, Liquid Nitrogen or Liquid Helium to cool Type I(Lead/Aluminum) superconductor? I know its best to use Liquid Helium, but can I use Liquid Nitrogen and go below the BC of those materials?

Just curious if anyone knew about any progress with higher critical temperature superconductors, whether they're cuprates or metals, what is the mixture of elements, you know just any news. I was thinking about looking into making a high tc superconductor of my own and yes I know that if its...

I am doing some reading about superconductors and Josephson Junctions and was wondering about one of their exhibited behaviors. I read a statement claiming that if a frequency (AC current) is applied to the terminals of a Josephson Junction by microwave irradiation then the current of cooper...

In ordinary conductors, electrons can lose energy by two mechanisms. First, by electron scattering on atoms of the lattice bulk, thus transferring energy to the bulk and increasing the bulk's temperature. This is the main contribution to the conductor resistance. But there is also the...

Hi I know that BCS theory predicts Cooper pairs which move as a Bose condensate in superconductors. But why would scattering lead to a zero resisitance state because surely the Cpairs would provide resistance. I realize that superconductors have zero resistance but just can't really seee why?

Hi all, I have a question which relates to induction and one potentially useful property of superconductors which seems to suggest one intriguing posibility. I won't say what just yet since my science is potentially a bit rusty, so don't want to sound like a fool. As I understand it, after...

What is the highest temperature a superconductor can work today?

Suppose you a have superconducting loop connected to a 9V battery. What is the current through it? With a resistance of 0Ω, V = IR gives ∞. I don't think that can be right... If it were, V=\frac{I}{nAe} would give an infinite velocity... Does that equation even apply to superconductors?

I will be trying to build an electric motor using superconductors and I have some general concept questions in regards to how the behavior might be different from ordinary wires. 1. The Meissner effect, expulsion of magnetic fields from the superconductor. If you construct a solenoid out of...

I asked about superconductors in another paost, and what I got was how superconductivity is achieved, and how electrons are attracted together via interactions with atomic nuclei. My question is, what exactly is a cooper pair? To me, when I think of the word pair, I immediately imagine the...

Electricity has been a mysterious entity plaguing my mind since last year when I learned about it in class. I am unable to understand why electrons move the way they do when a circuit is formed, nor what is the driving force to make them do so (which is voltage difference, and I don't understand...

As i have learnt, the lenz's law is not the cause of the meissner effect.This can also be proved by some experiments.I was wondering what may be the real cause for the meissner effect? As i don't know the cause, i have no idea, in which part of physics i must post this query.

I ran into the following article by Varma, Higgs Boson in Superconductors http://arxiv.org/abs/cond-mat/0109409 Varma compares the Gross-Pitaevskii equation with the Higgs Lagrangian and calculates the elementary excitations. He shows that although symmetry is broken in both cases, Higgs...

What is a rough figure for the wavelength of the moving electrons in a superconductor? Or is there no easy answer for that?

My prof. asked: "What is the mechanism that causes certain materials to exhibit superconductivity at temperatures much higher than around 25 kelvin?" then until now it remain a question to me?.. so anyone have an idea? thank you.

Hello Forum gold, silver, copper are the best electrical conductors are room temperature. But they cannot be superconductors: there is no finite, low critical temperature at which they become superconductors... But what if we could bring their temperature to 0 kelvin? I believe that all...

Homework Statement consider an infinite superconducting slab of thickness 2d (-d<=z<=d), outside of which there is a given constant magnetic field parallel to the suface. Hx =Hz=0 hy= H0 (some value for z<d and z>-d) , with E vector= D vector=0 everywhere. compute H vector < J vector inside...

What is "kinetic capacitance" in superconductors or in solid state in general? Hi, I would appreciate it if anyone could explain to me what "kinetic capacitance" is, particularly in the context of superconductors or solids. I understand "kinetic inductance" which comes from the kinetic...

"Invention" Idea - Cheap Room-Temperature Superconductors Now? I propose that if you encase a superconducting material along with liquid helium (or some other coolant) inside a Dewar flask or Thermos and then insert liquid helium, and then cool the superconductor+liquid helium once down to...

Help with Very High Temperature superconductors (28°C!) Since several months researchers on www.superconductors.org have published results about Very High Temperature SuperConductors (VHTSC). A new result has been recently published: http://www.superconductors.org/28c_rtsc.htm I don't...

Well, right now I am a high school student taking AP Physics C, BC cac and AP chem and I want to self learn about superconductors. I have looked online and at my school library and have had little to no luck finding any documents that I can learn from. My goal is to learn about superconductors...

[credit to wikipedia] So it would appear that the type 1 meissner effect allows for the localized increase of magnetic flux density (as the displaced field must go somewhere, the B field is somewhat larger at the surfaces of the superconductor then elsewhere, and in fact is a higher value...

are superconductors dia magnetic materials?? if so, what are similarities between them??

I don't understand the mechanism by which "flux tubes" create heat, and are pinned by impurities in a type II superconductor. When Bc1<B<Bc2 I understand magnetic flux will penetrate the material in the form of flux tubes. Then the current in the superconductor exerts a force on these tubes...

Guys I have a problem. Maybe, it's is a stupid one, but I really need help to comprehend something. I'm writing a report about applications of superconductivity. I chose the MagLev trains applications. Let's say, everything was fine until I read about the Meissner Effect. Now I have my mind...

my knowledge of superconductors is limited to the fact that they are substances whose resistnce bcme zero below a certain temperature and current once established continues to flow indefinitely. a) how can substances behave as supercondictors?(i don't know the name of any...superconducting...

Why is it called "fluctuation conductivity" in superconductors? Hello, In the work of Aslamazov-Larkin and many more, conductivity of a superconductor is calculated from the time dependent Ginzburg-Landau (TDGL) theory. They call it "fluctuation conductivity" bellow and above critical...

Hello, I'm studying about superconductivity. So far I understand that the material needs have zero resistance and meissner effect to be a superconductor. But why materials such as copper or gold are not superconductors? I think it's something to do with some quantum effect like cooper...

By definition, superconductors are conductors with zero resistance at low temperatures. Do superconductors exist ideally, i mean whether zero resistance is practically possible?

Hello, I would be grateful is someone could explain what the irreversibly temperature in type II superconductors is. I have just done some NMR experiments on MgB2 and get a lineshape change at the the irreversibility temperature as opposed to the field corrected Tc, so I believe it has...

Hello, Conductivity \sigma (\omega, k) in Fourier space is defined by J(\omega, k)= \sigma (\omega, k) A(\omega, k) In most cases the local limit of k\rightarrow 0 is a good approximation particulalry in type I superconductors and HTC superconductors. I am interested in cases...

I am a freshman at Wright State University in Ohio. I am trying to decide where to eventually place my focus at. I understand it is early but I am one of those people who puts in 20 hours of "fun" study time on the side while still doing my college work. To me Superconductors, Genetic...

Hi everyone, just a quick question. I just heard someone say a superconducting electromagnet does not produce heat, which I find very strange, since it seems that, since rate of heat energy being dissipated = voltage^2/resistance. Taking the limit as resistance goes to 0, with voltage held...

I have a question I'm unsure about. It's asking me to contrast the way defects in normal conductors impede the flow of electons whereas they facilitate the current in superconductors. I can explain why defects cause resistance in conductors and also why electrons encounter no resistance by...

As I understand it there are two types of superconductors, conventional and non-conventional. Conventional superconductors are explained by the BCS theory, my understanding of which being electrons pair up because the bending fields from their movement hold them together and there is not enough...

I hear how people create superconductors by taking a metal and freezing it to Absolute Zero(0 Kelvin). What are some methods to get this sort of tempuature? Can anyone help?

What is the meaning of zero resistivity in superconductors? I mean, what's the cause of zero resistivity in superconductors?

Here are some questions on superconductors that I would like ask- The first one is What are the differences between superconductors and infinite conductors?

Hi I've been searcing the WWW, but I can't seem to find an exact definition of a d-wave superconductor. Is a d-wave superconductor simply a superconductor, where the Cooper pairs are formed by d-shell electrons?

Hi I read on Wikipedia that a broken Cooper pair is called a Bogoliubov quasiparticle (source: http://en.wikipedia.org/wiki/Quasiparticle). Is that really true (if yes, then is there a difference between QPs in a metal and a superconductor)?

Various chemical formulae for the composition of superconductors quote the oxygen content, ie the number oxygen atoms present, as say Osub(10-delta). I would like to know the significance of delta.

Hi The dispersion of Bogolyubov quasiparticles in a d-wave superconductor is E(\mathbf k) = \pm \sqrt{\varepsilon (\mathbf k)^2+\Delta (\mathbf k)^2}, where ε(k) is the normal-state dispersion and ∆(k) is the gap dispersion. My question is: The Fermi surface (FS) of the normal...

Hi In superconductors, the fermions are interacting. In order to diagonalize our Hamiltonian (which contains the product of four fermion operators), we use Wick's theorem to approximate the product of four fermion operators by the product of two fermion operators. Now, a Hamiltonian...

Say you have a superconducting loop of copper. If there's an increasing magnetic field through it that induces an E field around the loop, how are the electrons moving when the field stops increasing? As I understand it the current is preserved. Is there some way to calculate the energy...

Years ago they showed on TV, that spinning superconductors sort of shield gravitational field. Now I read http://news.softpedia.com/news/The-First-Test-That-Proves-General-Theory-of-Relativity-Wrong-20259.shtml How serious is this to be taken?