MAGNETIC DEVICES HAVING STABILIZED FREE FERROMAGNETIC LAYER OR MULTILAYERED FREE FERROMAGNETIC LAYER

摘要

Magnetic multilayer structures, such as magnetic or magnetoresistive tunnel junctions (MTJs) and spin valves, having a magnetic biasing layer formed next to and magnetically coupled to the free ferromagnetic layer to achieve a desired stability against fluctuations caused by, e.g., thermal fluctuations and astray fields. Stable MTJ cells with low aspect ratios can be fabricated using CMOS processing for, e.g., high-density MRAM memory devices and other devices, using the magnetic biasing layer. Such multilayer structures can be programmed using spin transfer induced switching by driving a write current perpendicular to the layers. Each free ferromagnetic layer can include two or more layers and may be a multilayered free ferromagnetic stack that includes first and second ferromagnetic layers and a non-magnetic spacer between the first and second ferromagnetic layers.