Large Tunnel Magnetocapacitance Effect in FeCo/MgAlO/FeCo(001) Magnetic Tunnel Junctions

We investigate the frequency characteristics and voltage dependence of tunnel magnetocapacitance (TMC) in FeCo/MgAlO/FeCo(001) epitaxial magnetic tunnel junctions (MTJs). We have successfully observed a large TMC ratio of up to 456% at 140 Hz and 75 mV, which is the largest value ever reported for MTJs. The frequency characteristics and voltage dependence of the observed TMC characteristics can be reasonably explained by the calculation based on the extended Debye-Frölich model.