Superconductor Definition and 151 Threads

Hi everyone, I need some help to look if I did these calculations right.Let us assume a three dimensional magnetic field: ##\vec{B}(x,y,z) = B_x(x,y,z)\hat{x} + B_y(x,y,z)\hat{y} + B_z(x,y,z)\hat{z}## The equation for the force on a superconducting particle in a magnetic field is given by...

Hello, I consider an ideal superconductor with the gibbs-energy $$ d G=-SdT + VdP - \mu_0 M V dH$$ and helmholtz energy $$ dF = -SdT -P dV + \mu_0 V H dM$$ Assuming, that in the normal state the magnetization is too small, so that G_n(H) = G_n(H=0) and at the transition point H_c the...

Hi all, I am currently writing a report about superconductors, and am currently reading about how the band gap shows that single electrons are not the charge carriers responsible for superconductivity. However, I was confused when I read that electrons are fermions and as such there are no band...

So since a lot of electricity ran through a coil creates a magnetic field as sown in one of faradays most famous experiment what if the coil was a superconductor and will it improve the magnetic field and will it make one at all?

I was hoping someone could tell me the phonon frequency of the electrons for YBCO with hole doping of about .2 and a critical temperature of around 75-70°K at about 70°K. An answer in Hz would be preferred, or failing that, in cm-1 with the wave speed. Also, might the Kohn anomaly influence the...

Independent research person who is working with Type II Superconductors. Would enjoy talking with fellow research people to discuss the fine details of Type II materials, specifically electrons and energy.

If a field line is moved into a superconductor it meets resistance. This resistance is modeled by adding an image flux thread outside the superconductor which then attracts the flux thread being moved into the superconductor. Why is this attractive force an accurate model of the resistance a...

Hi everyone, I'm trying to simulated the XRD pattern of Bi2Sr2Ca2Cu3O10, but I'm having a problem of finding the basis of atom(and their respective position). Also its JCPDS is quite hard to find, so if anyone working with this, may you provide a link or articles about my problem. Thanks...

as we know, B=0 in superconductors, because of Messner effect. B=μ0(H+M) => H=-M => χ=-1 in CGS units: B=H+4πM => H=-4πM χ=-1/4π --- question: why χ=-0.01 not χ=-1/4π for 100% superconductors? :frown::oldshy:

Hey, guys, I encountered this and confused about it. "In a perfect conductor, an arbitrarily large current can be induced, and the resulting magnetic field exactly cancels the applied field." But I suppose, according to Faraday's law,the magnitude of emf is the rate of change of magnetic flux...

When reading some material concerning Ginzburg-Landau theory of superconductors, I got the following sentence: The appropriate thermodynamic potential for describing a superconductor in an applied magnetic field is the Gibbs free energy ##G## (natural variable ##H##) and not the Helmholtz free...

I am confused about the magnetic susceptibility vs. temperature curves (or MT) of superconductors (SCs). In the normal conduction state (I measured from 4.5K to 300K), the susceptibility curve can obey the Curie-Weiss law. But when I fitted the data via the Curie-Weiss law in a different...

I'm thinking of doing a science fair project having to do with a superconductor. However, the problem is that I have two things I don't understand, exactly what the science fair is asking for, but that's okay, I can always ask my teacher- And also, how I should start with this superconductor...

From what i have read on super conducting materials they require extremely low temperatures and that the structure of them becomes altered so that the atoms form a sort of uniform tube instead of more like a mesh pattern. Ie the atoms do not intefere with the passage of electrons/photons...

I know that BCS theory cannot explain high Tc superconductor. Most high Tc superconductors belong to type-II ones. Can BCS theory explain type-II conventional superconductor? How to predict high Hc2 and low Hc1 for type-II conventional superconductor in BCS theory?

Forgive me if some of my question sounds misguided or misinformed - I'm new to the flux pinning game. I want to be able to modify the height of a quantum locked superconductor. My original plan was to levitate the superconductor over an electromagnet and modify the current to said magnet...

Hi, I did a forum search on the topic , but from all the threads I went through I still have doubts about my understanding , please correct me. Both superconductors and ordinary conductors are metals or metal alloys.Both have ion lattice and electrons that are the moving , current , heat...

I see in the main page an article touting a record setting 20,000 amps flowing in a superconductor. Normally, with resistance in the circuit, it is a simple matter to multiply volts times amps to come up with watts or joules/second. But in a superconductor the resistance is zero so 20,000...

Homework Statement I have a lot of information about 2 different superconductor materials; indium and lead. The indium is pretty much 100% indium with no impurities, and the lead is unknown purity. I have the temperatures and magnetic fields at which they are superconducting and the...

I am starting to work with the high temperature superconductor BSCCO (Bi–Sr–Ca–Cu–O). I have read that the carriers of superconducting current is hole pairs. (As opposed to electron-pairs in normal superconductors) I am trying to understand how the transport would work. If I contact it with...

Sorry - a very vague question: Could a superconductor be used to detect dark matter? The dark matter might interact with electrons in the superconductor giving them some momentum. These moving electrons would constitute a supercurrent which could be measured - maybe! Perhaps the...

Hi all, Does anyone know how the magnetic field strength of a superconductor varies as distance from the outside of the superconductor? Aside from a superconductor being able to creates a stronger magnetic field than a regular dipole, does the strength still go down as 1/r^2 or does it...

Hi, What will happen if I connect an ideal battery across two ends of a superconductor? Assume all contacts are ideal, lossless. Is the current infinitive?

If you were to levitate a superconductor using a permanent magnet due to the effects of the Messiner Effect, and you were then to lift the permanent magnet with your own hands, would you be lifting the mass of the permanent magnet, the mass of the permanent magnet + the mass of the...

Homework Statement Why is it that for a superconductor \alpha<0,\beta>0 in the Ginzburg-Landau model wit free energy formulation E=\int d^3x\,\, \frac{\vec B^2}{2\mu}+\frac{1}{2m}|(-i\hbar\nabla-e\vec A)\psi|^2+\alpha|\psi|^2+\beta|\psi|^4 Homework Equations E=\int d^3x\,\, \frac{\vec...

Hey guys! I'm doing a science project on high temperature superconductors and i was just wondering, what kind of metals that can be bought will become a superconductor when put in liquid nitrogen. Liquid nitrogen of course is 63k so anything below 63 kelvins will not work, however if a metal...

URGENT: solenoid and superconductor questions Sorry I cross posted this, but I realized that general physics was probably a better place for it... I have a few questions regarding the levitation of a piece of superconductor using the field from a solenoid. In other words, I want to calculate...

a type II superconductor may not exhibit complete exclusion of magnetic field due to quantum vortices. It is my understanding that the magnetic field present will affect the number of vortices or fluxons present, but what is the relationship between magnetic field, and number of vortices in a...

The equation can be obtained from the fact that the "canonical momentum of the ground grstate of superconductor is zero", but where does this fact follow from. P.S. Jackson gives a vague reference to Kittel, which I couldn't find in his Introduction_to_solid_state/Quantum_theory_of_Solids.

Homework Statement Niobium metal becomes a superconductor when cooled below 9 K. Its superconductivity is destroyed when the magnetic field inside the superconductor exceeds 0.100 T. Determine the maximum current a 3.00-mm-diameter niobium wire can carry and remain fully superconducting, in...

What is the Resistivity of YBCO in superconductive state because it is not zero, or there would be not heat created so what is it or am I wrong? Explain to me where the heat from a current passing into a superconductor comes from.

Why is the magnetic field of a superconductor normally excluded?

A magnetic field is excluded in a superconductor so what happens to its electrical counterpart? Does it also become excluded? How do superconductors respond to external electric fields?

Does anyone know how one might obtain a chemical called "Mercury Thallium Barium Calcium Copper-Oxide"(Hg12Ti3Ba30Ca30Cu45O125)? I searched online, but I couldn't find any vendors.

What's the possibility of developing a superconductor that is superconductive at room temperature? Developing such superconductor would be a very significant scientific advancement and will certainly change out lives.

Hello, I wonder: 1-) whether the (Cooper pair) current is conserved in a superconductor? 2-) and, how I can see it mathematically? 3-) are there any differences between the London theory and the BCS theory in regard to current conservation. I would appreciate any comments on these...

Hi, I posted this earlier in what I thought to be the "General Physics" section, but since it got deleted and I was notified that I posted in "GD" which is (general discussion?) I realized I did this by mistake so I am sorry. -------------------------- to my question Hi, What I...

Hello all, Superconductors are great, but obviously its tricky to keep them at such a low temperature for extended periods of time. This poses a problem for engineering applications. What about the feasibility of cooling the superconductor, then placing the material in a vacuum chamber...

I am currently an intern at a superconductor lab and have been faced with a personal curiosity. I work with a device that determines the critical temperature at which the material stops superconducting. This device is composed of an electric temperature probe and two coils of wire which are...

As I understand it in a normal superconductor electromagnetic fields are extinguished by opposing fields produced by induced superconducting currents. This causes photons to only penetrate a short distance into a superconductor. I understand that one can imagine the Higgs field as a kind of...

Theoretically, if I had my usual, cheap, room-temperature superconductor :smile:, what could I do with it?

I have learned that as temperature decreases, the motion of particles in a lattice decreases.Then how can a cooper pair move so swiftly across the lattice when temperature is considerably low?Can anyone please explain?

I was wondering what it would be like if you had a permanent magnet inside the core of a material capable of obtaining the superconducting state. And you cooled it down so that it becomes a superconductor. Assuming it didn't explode; would it just condense the magnetic field into some...

Hey all, I'm just working through the london theory of superconductors. I've dervied the london penetration depth, the distance for the amplitude to drop by a factor of 1/e... Seems simple... Now my book talks about applying a an ac magnetic field to a superconductor. How would the field...

What would happen if a magnetic field is generated inside of a Type II superconductor? Would there be flux tubes?

I am modeling a magnetic coil array in Opera v15. My current project uses a CosΘ Coil inside a Metglas cylinder (Ferromagnetic) inside a Pb cylinder (Superconducting) at 4ºK. The method used to specify the a material in Opera is to specify the Coercivity and Relative Permeability. If I had...

Hello! Me and some friends are doing a phyics project at school. The theme is superconductor. The school have a superconductor, but its broken i half (like two half moons). My question is: will this effect the result? And does the thickness matter how far above the surfice it will levitate...

Go easy on me, as I have no formal condensed matter education and just the highest undergraduate quantum physics and chemistry offered at my university. I read a lot of papers and did extra studying while taking those classes, but I'm definitely rusty on the mathematics. Feel free to give me...

In the wake of recent metallic hydrogen news, and the fact that metallic has long been thought to be a room temperature superconductor, I began to ponder about the age old question of superconductor levitation. Now that we are no longer restricted by temperature requirements, perhaps levitation...

A flux quantum is approx. equal to 2*(10)^(-7) gauss cm*cm. A type 2 superconductor is placed in a small magnetic field which is then slowly increased till the field starts penetrating the superconductor. THe strength of the field at this point is 2/pi*(10)^(5) gauss. The penetration depth...