Magneto resistor is a type of resistor whose resistance changes when an external magnetic field is applied. In other words, the flow of electric current through the magneto resistor changes when an external magnetic field is applied to it.
Magnetic field is the region present around a magnetic object within which other objects experience an attractive or repulsive force.
The magneto resistors that are placed in the magnetic field will experience a change in resistance. When the strength of the magnetic field is increased, the resistance of magneto resistors also increases. On the other hand, when the strength of magnetic field is reduced, the resistance of magneto resistors decreases. This change in resistance is caused by the magneto resistive effect.
In the absence of magnetic field, the charges carriers in the material move in a straight path. Therefore, electric current flows in a straight path. When the magnetic field is applied to the material, the magnetic forces cause the mobile charge carriers (free electrons) to change their direction from direct path to indirect path. This increases the length of electric current path.
Magneto resistive effect is the property of some materials, which causes them to change their resistance under the presence of magnetic field. This magneto resistive effect occurs in materials such as semiconductors, non-magnetic metals, and magnetic metals.
For the last several years, the search for materials with large magnetoresistances (MRs) and studies on related phenomena have been in the forefront of worldwide research activity owing to their widespread application in the field of magnetic sensors, magnetic memory devices, magnetic switches, etc. The highest value of MR in principle can be achieved if the resistivity of the material can be transformed from an extreme insulating material (such as mica) to a very good metallic material (such as copper) by applying a magnetic field.
Colossal magnetoresistance, in which the resistivity changes by several orders of magnitude (~ 104%) in an external magnetic field, occurs mainly in phase-separated oxide materials, namely, manganites, owing to the phase competition between the ferromagnetic metallic and antiferromagnetic insulating regions.
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