Voigt–Thomson law

Voigt–Thomson law describes anisotropic magnetoresistance effect in a thin film strip as a relationship between the electric resistivity and the direction of electric current:

$\rho (\vartheta )={\rho }_0+\mathrm{\Delta }\rho \cdot co{s}^2\vartheta$

where:

$\vartheta$ is the angle of direction of current in relation to the direction of magnetic field

${\rho }_0$ is the initial resistivity

$\mathrm{\Delta }\rho$ is the change of resistivity (proportional to MR ratio)

The equation can also be expressed as:

$\rho (\vartheta )={\rho }_{\parallel }\cdot co{s}^2\vartheta +{\rho }_{\perp }\cdot si{n}^2\vartheta$

where:

${\rho }_{\parallel }$ is the parallel component of resistivity

${\rho }_{\perp }$ is the perpendicular component