Magnetic tunnel junctions and their applications

Abstract

Magnetic tunnel junction (MTJ) consists of at least two ferromagnetic layers, separated by an insulating tunnel barrier of amorphous aluminum oxide Al-O or monocrystalline (100)MgO. The magnetization direction of the free ferromagnetic layer (top electrode) is used for information storage. The tunnel resistance of the memory bit cell is either low or high, depending on the relative orientation of magnetizations (parallel or antiparallel) of the free layer with respect to the fixed layer (bottom electrode). The sense current flows perpendicular to the film plane of MTJ for the random access memory (MRAM) cell or reprogrammable magnetic logic (RML) system. The MRAM or RML bit cell is programmed by the magnetic field, generated by current flowing through conductors.