What is the Hall Effect?

About Hall Effect:

• It is named after American physicist Edwin H. Hall, who first introduced the theory to the world in 1879.
• Hall discovered that when a conductor or semiconductor with current flowing in one direction was introduced to a perpendicular magnetic field, a voltage could be measured at right angles to the current path; this measurable voltage is the Hall Effect.
• How does it work?
  • It takes place when current flowing through a conductor, which is a material such as copper or silver permits electrons to flow freely across the entire surface area.
  • The electrons begin to flow in a straight line from one side of the conductor to the other.
  • If a magnetic field near the conductor is introduced, it would disturb the flow of the electrons due to the force applied.
  • This is called Lorentz force, which is the force on a charged particle due to electric and magnetic fields.
  • The magnet’s north pole pulls the negative electrons to one side of the conductor and deflects the positive electrons to the other side of the conductor.
  • If a voltage tester is put between the two sides, a voltage reading will be given because there is current between the positive and negative electrons; by retrieving this measurable voltage, the Hall Effect principle is put into practice.
  • In a semiconductor such as silicon or germanium, the drift velocity of electrons is a lot quicker due to the material used.
  • This results in a stronger Hall effect which corresponds to a larger voltage reading being detected and therefore a more precise reading being taken.
  • The Hall effect is used in several different products, such as sensors, joysticks, and switches.
• A Hall effect sensor is a device to measure the magnitude of a magnetic field.
  • Its output voltage is directly proportional to the magnetic field strength through it.
  • Hall effect sensors are used for proximity sensing, positioning, speed detection, and current sensing applications.

Recent Findings:

• For a long time, people thought the Hall effect only worked when the magnetic field was applied perpendicular to the plane of the film.
• The recent findings show that a Hall response tied to magnetization can occur in more than one direction.
• That gives physicists a new way to investigate multidimensional magnetic and topological structures in condensed matter systems.