Hall Effect

When a material carrying an electric current is placed in a magnetic field that is perpendicular to the current, the Hall Effect occurs, resulting in the development of a transverse electric field in the material. Edwin Herbert Hall discovered the Hall Effect in 1879 and published his findings in 1880. 

Hall Effect

“The development of a transverse electric field in a solid material when it is carrying an electric current and is placed in a magnetic field that is perpendicular to the current is referred to as the Hall effect”. 

The electric field, also known as the Hall field, is produced as a result of the force exerted by the magnetic field on the moving positive or negative particles that make up the electric current, which results in the current flowing. If the current is made up of positive particles moving in one direction, negative particles moving in the opposite direction, or a combination of the two, a perpendicular magnetic field displaces the moving electric charges in the same direction sideways at right angles to both the magnetic field and the current flow. The accumulation of charge on one side of a conductor leaves the other side of the conductor oppositely charged, resulting in a potential difference between the two sides. This difference may be detected as either a positive or a negative voltage by a suitable metre. According to the sign of this Hall voltage, either positive or negative charges are responsible for carrying the current.

In metals, the Hall voltages are typically negative, indicating that the electric current is composed primarily of negatively charged particles, such as electrons, moving through the material. Hall voltage, on the other hand, is positive for a few metals, including beryllium, zinc, and cadmium, indicating that the movement of positively charged carriers, known as holes, is responsible for the conduction of electric current in these metals. Because in semiconductors current is made up of the movement of positive holes in one direction and the movement of electrons in the other, the sign of the Hall voltage indicates which type of charge carrier is predominating. The Hall effect can also be used to measure the density of current carriers, their freedom of movement, or mobility, as well as to detect the presence of a current in a magnetic field, according to the manufacturer’s specifications.

While the Hall voltage that develops across a conductor is directly proportional to the current, to the magnetic field, and to the nature of the particular conducting material itself, it is inversely proportional to the thickness of the material in the direction of the magnetic field; the Hall voltage is directly proportional to the current, the magnetic field, and the nature of the particular conducting material itself Because different materials have different Hall coefficients, they produce different Hall voltages when subjected to the same size, electric current, and magnetic field conditions as one another. Hall coefficients can be determined experimentally and may vary depending on the temperature used to calculate them.

The Hall Effect is based on the following principle:

Essentially, the principle of Hall Effect states that, upon the introduction of a current-carrying conductor or a semiconductor into a perpendicular magnetic field, a voltage can be measured at a right angle to the current path. The Hall Effect is the term used to describe the phenomenon of obtaining a measurable voltage.

Theory

When a conductive plate is connected to a circuit containing a battery, a current begins to flow through the circuit. The charge carriers will travel in a straight line from one end of the plate to the other end of the plate. Magnetic fields are produced as a result of the movement of charge carriers. When a magnet is placed near a plate, the magnetic field of the charge carriers is distorted, causing the charge carriers to scatter. The charge carriers’ straight flow is disrupted as a result of this. Lorentz force is the term used to describe the force that causes charge carriers to flow in an unexpected direction.

The negatively charged electrons will be deflected to one side of the plate and the positively charged holes will be deflected to the other side of the plate as a result of the distortion in the magnetic field of the charge carriers. There will be a potential difference generated between both sides of the plate, which is known as the Hall voltage, and this difference can be measured with a metre.

The formula for calculating the Hall voltage, denoted as VH, is as follows:

VH = IBqnd

Here,

The current flowing through the sensor is denoted by I.

The magnetic field strength is denoted by the letter B.

The charge is represented by the letter q.

The number of charge carriers per unit volume is denoted by the letter n.

The sensor’s thickness is denoted by the letter d.

Conclusion

The moving charge carriers in a conductor subjected to a magnetic field experience a transverse force from the magnetic field, which tends to push them to one side of the conductor when an electric current flows through the conductor.  This magnetic influence will be balanced by a buildup of charge at the sides of the conductors, resulting in the production of a measurable voltage between the two sides of conductor. This measurable transverse voltage is referred to as the Hall effect, after the scientist E. H. Hall, who discovered it in 1879 and named it so.