The Hall effect is a phenomenon that occurs when a magnetic field is applied perpendicularly to the direction of electric current flowing through a conductor or semiconductor. As a result, a transverse voltage—called the Hall voltage—develops across the material, perpendicular to both the current and the magnetic field.
This happens because the magnetic field exerts a Lorentz force on the moving charge carriers (electrons or holes), pushing them to one side of the conductor. This accumulation of charge creates an electric field, which builds up until it balances the magnetic force, resulting in a steady transverse voltage.
Key points about the Hall effect:
- The polarity of the Hall voltage indicates the type of charge carriers (negative for electrons, positive for holes).
- The magnitude of the voltage is proportional to the current, magnetic field strength, and properties of the material.
- It occurs more noticeably in semiconductors than in metals.
The Hall effect is widely used in:
- Magnetic field sensors (like Hall effect sensors in smartphones and cars),
- Measuring carrier concentration and mobility in semiconductors,
- Current sensing and position detection.
The Hall effect not only provides insight into the nature of charge transport in materials but also has practical applications in electronic devices and instrumentation.