A magnetic tunnel junction (MTJ) is a device that uses a thin insulating layer to create electrical conduction between two ferromagnetic layers. The resistance of the MTJ depends on the relative alignment of the magnetization in the two magnetic layers.
Most current p-MTJs utilize body-centered cubic (bcc) FeCo(B) alloy magnetic electrodes and an MgO barrier.
Perpendicular Magnetic Anisotropy (PMA) is magnetic property in which the magnetization of a material naturally aligns along the direction perpendicular to the plane of the material, rather than lying in the plane. Here, PMA originates from the tetragonal strain and the value of PMA reaches 1 MJ/m3 with adequate strain.
Magnetic properties were characterized by a vibrating sample magnetometer(vibrating a sample in a magnetic field and measuring the resulting electrical signal) and polar magneto-optical Kerr effect.
The values for saturation magnetisation Ms tend to decrease with increasing Co concentration.
Magnetic anisotropic energy is given by
The perpendicular magnetic anisotropy (PMA) constant (K) indicates the strength of a material's preference for magnetization along a specific direction. K for the films tend to increase with increasing Co concentration.
Thermal stability is calculated as
Ep is the barrier energy -the energy needed for the magnetization of a material to switch between two stable directions.
Gilbert damping constant describes how quickly the magnetization in a material stabilizes after being applied magnetic field or spin torque. The threshold of the switching current is proportional to the Gilbert damping constant α. The low Gilbert damping for magnetic free layer is preferable for low power consumption in STT-MRAM(spin-transfer-torque magnetoresistive random access memory).
Source:
https://www.tandfonline.com/doi/full/10.1080/14686996.2024.2421746#abstract
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