Patent ID: 8971100
Filing Date: 2015-03-03
Classification: G11C,Y10S

Abstract:
1. A method for initializing perpendicular magnetization directions of magnetic layers in a set of MRAM elements with each element having at least one free layer and at least first and second fixed layers, the first and second fixed layers having different coercivities, the set of MRAM elements including at least one element that serves as a reference element, the method comprising: applying a first externally generated magnetic field to the set of MRAM elements, the first externally generated magnetic field having a first field direction and having a first field magnitude sufficient to switch magnetization directions of the free layer and the fixed layers of each element into a first perpendicular magnetization direction; and after the first externally generated magnetic field has been removed, applying a second externally generated magnetic field to the set of MRAM elements, the second externally generated magnetic field having a second field direction opposite to the first magnetic field and having a second field magnitude that is weaker than the first field magnitude, the second field magnitude being sufficient to switch the magnetization directions of the free layer and the first fixed layer into a second perpendicular magnetization direction while leaving the second fixed layer in the first perpendicular magnetization direction.