Patent ID: 7440314
Filing Date: 2008-10-21
Classification: G11C

Abstract:
1. A magnetoresistive random access memory comprising: a plurality of first wirings which is extended in a first direction; a plurality of second wirings which is extended in a second direction which is substantially perpendicular to said first direction; a plurality of memory cells, each of which is placed correspondingly to each of positions where said plurality of first wirings is crossed with said plurality of second wirings; a second sense amplifier which detects a state of a reference cell on the basis of an output from said reference cell provided by corresponding to a reference wiring among said plurality of second wirings, among said plurality of memory cells; and a first sense amplifier which detects a state of one of said plurality of memory cells on the basis of an output from said reference cell and an output from said one of the plurality of memory cells, which is different from said reference cell, wherein each of said plurality of memory cells includes a magnetic tunneling junction element having a laminated free layer in which a magnetization direction is reversed correspondingly to data to be stored, wherein said magnetic tunneling junction element has a magnetization easy axis direction which is different from said first and second directions, and wherein a toggle operation to reverse a magnetization of said laminated free layer, for a selected cell as one of plurality of memory cells which corresponds to a selected first wiring selected among said plurality of first wirings and a selected second wiring selected among said plurality of second wirings, is executed by a series of current controls in which a first write current is supplied to said selected first wiring followed by a second write current to be supplied to said selected second wiring next, then, said first write current is stopped followed by said second write current to be stopped, wherein said first write current and said second write current are larger in said toggle operation executed for said reference cell than in said toggle operation executed for one of said plurality of memory cells which is different from said reference cell.