Quantum magnetocapacitance in ferromagnetic nanocontacts

Using the scattering matrix theory, magnetocapacitance properties are investigated in magnetic nanocontacts. In the ferromagnetic alignment, the effective potential of the exchange splitting energy acts as a quantum well for spin-up electrons and as a quantum barrier for spin-down ones, which results in spin-dependent capacitance. When the system switches from the ferromagnetic alignment to the antiferromagnetic alignment induced by an external magnetic field, the capacitance changes correspondingly. This magnetocapacitance effect can be expected to be useful in designing a magnetocapacitor.