Eddy-current tunnel magnetic contacts with a composite free layer

A new method was offered to design tunnel magnetoresistive CoFeB/MgO/CoFeB contacts with free layer vortex magnetization configuration. Contacts are made using electron-beam lithography methods and have lateral sizes of $\sim$700 nm. The achieved tunnel magnetoresistance effect was equal to 80–120% for various samples. Thanks to low coercitivity, the magnetoresistance curve has a linear section without magnetic hysteresis that corresponds to vortex offset from the central position. Such types of contacts show spin-transfer diode properties – they feature rectification of high-frequency signals on vortex magnetization configurations.