SUPERCONDUCTIVITY INSTRUCTOR-DR. MARIA MERCY A. NAME Sparsh Sharma Anurag Patil Sai Prakash ID NO. 2015A1PS795H 2015A3PS311H 2015A1PS749H

INTRODUCTION SPARSH SHARMA 2015A1PS795H

BCS THEORY BCS THEORY IS THE FIRST MICROSCOPIC THEORY OF SUPERCONDUCTIVITY. THE BEHAVIOUR OF SUPERCONDUCTORS SUGGESTS THAT ELECTRON PAIRS ARE COUPLING. THESE COUPLED ELECTRONS CAN TAKE THE CHARACTER OF A BOSON AND CONDENSE INTO THE GROUND STATE. THIS PAIR CONDENSATION IS THE BASIS FOR THE BCS THEORY OF SUPERCONDUCTIVITYBCS THEORY THE EFFECTIVE NET ATTRACTION BETWEEN THE NORMALLY REPULSIVE ELECTRONS PRODUCES A PAIR BINDING ENERGY ON THE ORDER OF MILLI-ELECTRON VOLTS, ENOUGH TO KEEP THEM PAIRED AT EXTREMELY LOW TEMPERATURES.

“SUPERCONDUCTING CURRENT IS A SUPER FLUID OF COOPER PAIRS ”

MEISSNER’S EFFECT The German physicists WALTHER MEISSNER and ROBERT OCHSENFELD discovered this phenomenon in 1933 using tin and lead samples. It is the expulsion of magnetic fields from the superconductors,i.e, no magnetic lines of force crosses the material. Further this is achieved at the critical temperature. Also there are two types of superconductors based on the applied magnetic field.

SUPERCURRENTS

SUPERCONDUCTIVITY NAME: SAI PRAKASH SEETHAKA ID: 2015A3PS311H SECTION: LS 5 GROUP 39 INSTRUCTOR:MARIA MERCY AMUTHA A

what is superconductivity? Complete disappearance of electrical resistance in various solids when they are cooled below a characteristic temperature. This temperature may vary for different materials but generally it is below 20 Kelvin. ________________________________________________________________ What is a superconductor? A substance which is capable of becoming superconducting at sufficiently lower temperatures. Example: Mercury(Hg) at temperature 4.2 Kelvin

SUPERCONDUCTING LEVITATION Why levitation occurs? Superconductors expel magnetic field, and hence repel magnets. This repulsion can be stronger than gravity, which leads to levitation. This is the most fascinating manifestation of superconductivity. By using this principle magnetic levitation trains (Maglev trains) are designed. This is a floating train for land transportation which is supported by either electromagnetic attraction or repulsion. These trains were conceptualized during early 1900s.

Two types of Maglev trains are in service based on EMS and EDS. Electromagnetic Suspension (EMS) uses the attractive forces between the magnets that are present on the train’s side and on the track. The attraction from magnet keeps the train at a distance of half an inch above the track. Electrodynamic suspension (EDS) systems are almost similar to EMS but this uses the repulsive forces to run the train. This repulsive force from magnet keeps the train at a distance ranging from half an inch to four inches

ARE THESE TRAINS BENFITIAL? These trains have several advantages than normal trains These are less expensive to operate and maintain because of the absence of friction. Parts of the train will not get damaged easily as there will be no contact to the track while travelling. These trains produce very little air pollution which is ecofriendly. Though there are many advantages but these trains are not used in many countries as it is cost effective.

HIGH TEMPERATURE SUPERCONDUCTORS BY : ANURAG.R.PATIL 2015A1PS749H

WHAT ARE HIGH TEMPERATURE SUPERCONDUCTORS ? High temperature superconductors are those superconductors which do not require extremely low temperature to attain critical temperature. Discovered by Georg Bednorz and Alex Muller in 1986.

SUPERCONDUCTOR TIMELINE

CURRENT COMMERCIAL APPLICATIONS Magnetic Resonance Imaging (MRI) Nuclear Magnetic Resonance (NMR) High-energy physics accelerators Plasma fusion reactors Industrial magnetic separation of kaolin clay

EMERGING APPLICATONS Communications- HTS filters have come into widespread use in cellular communications systems. Industry - HTS can be used to substantially reduce electrical losses due to large motors operating at high power. Medicine - Advances in HTS promise more compact and less costly Magnetic Resonance Imaging (MRI) systems with superior imaging capabilities

MRI