Undergraduate
  1. Classical mechanics  1.1. dynamics  1.1.1. Motion in one dimension  1.1.2. Motion in two dimensions  1.1.3. projectile motion  1.1.4. Relative speed  1.1.5. Uniform circular motion  1.1.6. Non-uniform circular motion  1.1.7. Reference frames and transformations  1.2. Newton's Laws of Motion  1.2.1. First law of motion  1.2.2. Second law of motion  1.2.3. Third Law of Motion  1.2.4. Applications of Newton's Laws  1.2.5. Friction and its types  1.2.6. Free Body Diagram  1.2.7. Constraints and pseudo-forces  1.3. Work and Energy  1.3.1. work done by the force  1.3.2. Work–energy theorem  1.3.3. Kinetic energy  1.3.4. Potential energy in classical mechanics  1.3.5. Conservative and non-conservative forces  1.3.6. Energy Conservation  1.3.7. Power and efficiency  1.4. Speed and collisions  1.4.1. Linear momentum  1.4.2. Conservation of momentum  1.4.3. Impulse and impact force  1.4.4. Elastic and inelastic collision  1.4.5. Center of mass and speed  1.4.6. Rocket Propulsion  1.5. Rotational motion  1.5.1. Torque and Angular Momentum  1.5.2. Moment of inertia  1.5.3. Rotational Kinematics  1.5.4. Rotational Energy  1.5.5. Rolling Motion  1.5.6. Precession and gyroscopic motion  1.6. Gravitational force  1.6.1. Newton's law of universal gravitation  1.6.2. Gravitational potential energy  1.6.3. Orbital mechanics  1.6.4. Kepler's laws of planetary motion  1.6.5. Gravitational field and potential  1.7. Fluid mechanics  1.7.1. Pressure and Pascal's Principle  1.7.2. Buoyancy and Archimedes' principle  1.7.3. Fluid Dynamics and Bernoulli's Principle  1.7.4. Viscosity and Poiseuille's law  1.7.5. Surface tension and capillarity  1.8. Oscillations and waves  1.8.1. Simple Harmonic Motion  1.8.2. Damped and driven oscillations  1.8.3. Coupled oscillations and common modes  1.8.4. Wave properties and types  1.8.5. Sound Waves and the Doppler Effect  1.8.6. Wave interference and superposition
  2. Electromagnetism  2.1. Electrostatics  2.1.1. Electric charge and properties  2.1.2. Coulomb's law  2.1.3. Electric field and electric potential  2.1.4. Gauss's Law  2.1.5. Capacitance and Dielectric  2.1.6. Electric dipole and potential energy  2.2. Electric circuits  2.2.1. Current and Resistance  2.2.2. Ohm's law  2.2.3. Kirchhoff's Laws  2.2.4. RC Circuit  2.2.5. AC Circuits and Reactance  2.2.6. Electric power and energy  2.3. Magnetism  2.3.1. Magnetic Fields and Forces  2.3.2. Ampere's Law  2.3.3. Magnetic dipole moment  2.3.4. Biot-Savart law  2.3.5. Magnetic Materials and Hysteresis  2.4. Electromagnetic induction  2.4.1. Faraday's Law  2.4.2. Lenz's law  2.4.3. Self and mutual induction  2.4.4. Transformers and Inductive Circuits  2.5. Maxwell's equations  2.5.1. Gauss's law for electricity  2.5.2. Gauss's law for magnetism  2.5.3. Faraday's law of induction  2.5.4. Ampere-Maxwell law  2.5.5. Electromagnetic waves
  3. Thermodynamics  3.1. Laws of Thermodynamics  3.1.1. Zeroth law of thermodynamics  3.1.2. First law of thermodynamics  3.1.3. Second Law  3.1.4. Third Law  3.2. Heat and work  3.2.1. Heat transfer (conduction, convection, radiation)  3.2.2. Thermal expansion  3.2.3. Heat engines and refrigerators  3.2.4. Carnot cycle and efficiency  3.3. Statistical mechanics  3.3.1. Maxwell–Boltzmann distribution  3.3.2. Entropy and Probability  3.3.3. Partition function  3.3.4. Fermi–Dirac and Bose–Einstein statistics
  4. Optics  4.1. Geometrical Optics  4.1.1. Reflection and Refraction  4.1.2. Mirrors and lenses  4.1.3. Optical Instruments  4.1.4. Fermat's principle  4.2. Wave optics  4.2.1. Interference in wave optics  4.2.2. Diffraction  4.2.3. Polarization  4.2.4. Coherence and holography
  5. Quantum mechanics  5.1. Wave–particle duality  5.1.1. Blackbody radiation in wave–particle duality in quantum mechanics  5.1.2. Photoelectric effect  5.1.3. Compton scattering  5.1.4. De Broglie wavelength  5.2. Schrödinger Equation  5.2.1. Time-independent Schrödinger equation  5.2.2. Particle in a box  5.2.3. Quantum Tunneling  5.2.4. Potential wells and obstacles  5.3. Quantum States  5.3.1. Wave function  5.3.2. Quantum operators  5.3.3. Heisenberg uncertainty principle  5.3.4. Angular momentum and spin
  6. Relativity  6.1. Special relativity  6.1.1. Lorentz transformations  6.1.2. Time expansion and length contraction  6.1.3. Relativistic energy and momentum  6.2. General relativity  6.2.1. Principle of Equivalence  6.2.2. Schwarzschild metric  6.2.3. Gravitational waves  6.2.4. Black holes and event horizons
  7. Solid state physics  7.1. Crystal structure  7.1.1. Bravais lattices  7.1.2. X-ray diffraction  7.1.3. Band theory  7.1.4. Phonons and lattice vibrations  7.2. Electrical and Magnetic Properties  7.2.1. Conductors, Semiconductors and Insulators  7.2.2. Superconductivity  7.2.3. Hall effect
  8. Nuclear and particle physics  8.1. Atomic Structure  8.1.1. Atomic Model  8.1.2. Nuclear binding energy  8.2. Radioactivity  8.2.1. Alpha, beta, gamma decay  8.2.2. Half life  8.2.3. Nuclear Fission and Fusion  8.3. Particle physics  8.3.1. Standard Model  8.3.2. Quarks and Leptons  8.3.3. antimatter  8.3.4. Fundamental interactions
  9. Astrophysics and cosmology  9.1. Stellar evolution  9.1.1. Star formation  9.1.2. Black holes and neutron stars  9.1.3. White dwarfs and supernovae  9.2. Cosmology  9.2.1. The Big Bang Theory  9.2.2. Dark matter and dark energy  9.2.3. Cosmic microwave background

Undergraduate → Solid state physics → Electrical and Magnetic Properties ↓


Superconductivity


Superconductivity is a fascinating physical phenomenon that occurs in certain materials when they are cooled below a specific critical temperature. It is characterized by two main properties: zero electrical resistance and the expulsion of magnetic fields, known as the Meissner effect. As a result, superconductors have numerous applications in fields such as medicine, electronics, and transportation.

Electrical properties of superconductors

The most striking feature of superconductors is their zero electrical resistance. Normally, when electric current flows through a regular conductor such as copper or aluminum, it faces some resistance, resulting in energy being dissipated as heat. However, superconductors can carry electric current without any energy loss.

Illustration of zero resistance

Copper Wire resistance Superconductors zero resistance

In mathematical terms, Ohm's law defines the relationship between voltage (V), current (I) and resistance (R) as follows:

    V = I * R

For a superconductor, since the resistance R is zero, the voltage across the superconducting material is also zero, making it suitable to conduct electricity efficiently.

Magnetic properties

Superconductors also exhibit unique magnetic properties. When a material becomes superconducting, it expels all magnetic fields from within it, a phenomenon known as the Meissner effect. This property allows superconductors to levitate magnets, as can be seen in maglev trains.

Illustration of the Meissner effect

Superconductors

This effect is a key feature that distinguishes superconductors from perfect conductors. In a perfect conductor, if a magnetic field is applied and then removed, the field remains trapped inside the material. However, in a superconductor, the field is completely expelled when the superconducting state is reached.

Types of superconductors

Superconductors are broadly classified into two categories based on their physical properties: type I and type II.

Type I superconductor

Type I superconductors are usually pure metals such as lead, mercury, and aluminum. They exhibit complete elimination of magnetic fields (perfect diamagnetism) and have a single critical magnetic field, H c. Above this field, they go into a normal state. The Meissner effect is fully observed, as shown above in the Meissner effect illustration.

Example materials

  • lead
  • Mercury
  • Aluminium

Type II superconductor

Unlike Type I, Type II superconductors do not lose their superconductivity immediately but gradually. They have two critical magnetic fields, H c1 and H c2. Between these two fields, they allow partial penetration of magnetic fields in quantized units called vortices. Type II superconductors are usually metallic compounds and high-temperature superconductors.

Example materials

  • Niobium-Titanium (NbTi)
  • Yttrium Barium Copper Oxide (YBCO)
  • Bismuth Strontium Calcium Copper Oxide (BSCCO)

Applications of superconductors

Due to their unique properties, superconductors are used in a variety of applications:

Magnetic resonance imaging (MRI)

MRI machines use superconducting magnets to produce the strong, stable magnetic fields needed to obtain detailed images of the body's interior without radiation.

Particle accelerators

Superconducting magnets are integral parts in particle accelerators such as the Large Hadron Collider. They help guide and accelerate charged particles to high energies.

Magnetic levitation

Maglev trains use superconductors for frictionless, high-speed travel. The repulsion or attraction of magnetic fields causes the train to rise above the tracks, providing a smooth and quiet ride.

Electric power applications

Superconductors are very useful for power applications such as transmission lines, transformers, and storage systems. They can significantly improve the efficiency and capacity of power grids by reducing losses in power transmission.

Future prospects

The discovery and development of high-temperature superconductors remains a vibrant area of research. Scientists are experimenting with different materials and conditions to make superconductivity practical at room temperature, which could revolutionize energy storage and transmission.

In conclusion, superconductivity is a fascinating quantum mechanical phenomenon with enormous potential for technological advancement. Understanding its properties – zero electrical resistance and expulsion of magnetic fields – opens the door to many innovative applications.


Undergraduate → 7.2.2


U
username
0%
completed in Undergraduate

← Prev (7.2.1)
Conductors, Semiconductors and Insulators
Next (7.2.3) →
Hall effect

Comments 



Superconductivity

https://www.physicsflow.com/ug/7.2.2?pfal=en