Effects of two in-plane fields on the magnetization reversal mechanism in magnetic tunnel junction elements

One of the potential applications of the spin tunnel junction is as magnetic random access memory (MRAM) elements. For MRAM application purposes, two in-plane perpendicularly applied fields are required during magnetization reversal. In this article, Lorentz transmission electron microscopy has been used to study the magnetization reversal mechanism of tunnel junction elements under the influence of two in-plane perpendicular fields. Four hundred NiFe/MnFe/NiFe/Al₂O₃/NiFeCo elements with differing shapes and sizes have been observed. When an in-plane Y field was applied to the hard axis followed by sweeping the X field along the easy axis, it was found that the number of elements in which 360° domain walls are observed to form decreases as the strength of the Y field increases, and that the magnetization reversal mechanism in the tunnel junction elements gradually changes from a domain wall motion mechanism to a moment rotation mechanism as the Y field increases. As expected, the reversal field (X field) reduces as the Y field increases. © 2002 American Institute of Physics.