Bat
Microbats make use of magnetoreception, in that they have a high sensitivity to the Earth's magnetic field, as birds do. Microbats use a polarity-based compass, meaning that they differentiate north from south, unlike birds, which use the strength of the magnetic field to differentiate latitudes, which may be used in long-distance travel. The mechanism is unknown but may involve magnetite particles.
Magnetoelectric effect
Historically, the first and most studied example of this effect is the linear magnetoelectric effect. Mathematically, while the electric susceptibility formula_1 and magnetic susceptibility formula_2 describe the electric and magnetic polarization responses to an electric, resp. a magnetic field, there is also the possibility of a magnetoelectric susceptibility formula_3 which describes a linear response of the electric polarization to a magnetic field, and vice versa:
The tensor formula_6 must be the same in both equations. Here, P is the electric polarization, M the magnetization, E and H the electric and magnetic fields. The SI Unit of α is [s/m] which can be converted to the practical unit [V/(cm Oe)] by [s/m]=1.1 x10 ε [V/(cm Oe)]. For the CGS unit, [unitless] = 3 x 10 [s/m]/(4 x π)