Dynamic switching process of sandwich-structured MR elements

The dynamic behavior of sandwich-structured magnetoresistive (MR) memory elements is studied analytically by solving Gilbert's equation together with the one-dimensional micromagnetic torque equation. The typical element is 2 mu m*20 mu m and consists of two 150-AA thick magnetic layers separated by a 50-AA thick nonmagnetic layer. The easy axis is along the short dimension of the element. The theoretical study shows that wall nucleation is present when the switching is driven by a field applied in the easy-axis direction, whereas switching by a field in the hard-axis direction is accomplished by coherent rotation. The switching speed predicted by this one-dimensional model is in the nanosecond range and increases linearly with the external fields.<
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