Magnetoresistive and Magnetocapacitive Effects in Tunnel Magnetic Junctions. Problems and Prospects of Practical Application

This work shows that when the magnetic electrodes in magnetic tunnel junctions are magnetized, a strong magnetic field gradient appears in the barrier nonmagnetic layer, which causes a spatial redistribution of the concentration of spin-polarized electrons in the magnetic metal/insulator interface region and leads to the appearance of an uneven distribution of electric charge. Such a magnetically induced charge affects the dielectric characteristics of the barrier nanolayer and leads to a change in the resistance and capacitance of magnetic tunnel junctions. Moreover, this effect is most pronounced in tunnel magnetic contacts with magnetic electrodes that have perpendicular anisotropy. The work contains experimental measurements of the tunnel magnetoresistance and tunnel magnetocapacity in magnetic tunnel junctions with perpendicular anisotropy of Tb22-Co5Fe73/Pr6O11/Tb19-Co5Fe76 electrodes and in Co80Fe20/Pr6O11/Co30Fe70 contacts, where the magnetic electrodes have uniaxial anisotropy in the plane. The change in resistance during magnetization reversal of Tb22-Co5Fe73/Pr6O11/Tb19-Co5Fe76 contacts reached 120% and of Co80Fe20/Pr6O11/Co30Fe70 contacts it did not exceed 40%. The change in capacitance during magnetization reversal of Tb22-Co5Fe73/Pr6O11/Tb19-Co5Fe76 contacts reached values of 110%, and of Co80Fe20/Pr6O11/Co30Fe70contacts it reached values of 45%. In work the scheme and the principle of recording and reading information from an MTJ-based storage medium also is given.