Hall Effect

Hall Effect Latest News

Scientists recently discovered an unexpected form of the Hall effect, overturning the long-held assumption that this electrical response only appears when a magnetic field points perpendicular to a material. 

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?
  • The Hall effect takes place when you set current flowing through a conductor, which is a material such as copper or silver that 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 you were to introduce a magnetic field near the conductor, 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 you then put a voltage tester between the two sides, you will be given a voltage reading because there is current between the positive and negative electrons; by retrieving this measurable voltage, you are putting the Hall Effect principle 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. 

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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.

News: SD