MRAM cell requiring low switching field
AssigneeMotorola, Inc.
InventorsEugene Chen, Saied N. Tehrani
Life of this patent
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Abstract
A low switching field multi-state, multi-layer magnetic memory cell including two layers of magnetic material stacked in parallel, overlying relationship and separated by a layer of non-magnetic material so as to form a portion of a multi-layer magnetic memory cell. The two layers of magnetic material being formed so that the width is less than the length and less than a width of magnetic domain walls within the two layers of magnetic material, setting a shape anisotropy easy axis along the length thereof. At least one of the two layers of magnetic material having a magnetic anisotropy generally parallel to the width of the layers of magnetic material.
Claims8
A low switching field multi-state, multi-layer magnetic memory cell comprising:
- two layers of magnetic material stacked in parallel, overlying relationship and separated by a layer of non-magnetic material so as to form a portion of a multi-layer magnetic memory cell, the two layers of magnetic material having a length and a width;
- the width of the two layers of magnetic material being less than the length and less than a width of magnetic domain walls within the two layers of magnetic material setting a shape anisotropy easy axis along the length thereof;
- and
- at least one of the two layers of magnetic material having a magnetic anisotropy generally parallel to the width of the two layers of magnetic material, and
- wherein the cell is one of an in-plane type and a tunneling type of magnetic random access memory.
A low switching field multi-state, multi-layer magnetic memory cell including first and second layers of magnetic material with a layer of non-magnetic material sandwiched therebetween, at least one of the first and second layers of magnetic material having a shape anisotropy generally described by the expression K.sub.D sin.sup.2 .theta. and a magnetic anisotropy generally described by the expression -K.sub.m sin.sup.2 .theta., where K.sub.m is a magnetic anisotropy energy density, K.sub.D is a demagnetization energy density, and .theta. is an angle between the shape anisotropy easy axis and the magnetization vector.
A low switching field multi-state, multi-layer magnetic memory cell comprising:
- a plurality of layers of magnetic material stacked in parallel, overlying relationship and separated by layers of non-magnetic material so as to form a multi-layer magnetic memory cell having a length and a width;
- the width of the multi-layer magnetic memory cell being less than the length and less than a width of magnetic domain walls within the layers of magnetic material setting a shape anisotropy easy axis along the length of the multi-layer magnetic memory cell;
- and
- at least one of the plurality of layers of magnetic material having an easy axis magnetic anisotropy generally parallel to the width of the multi-layer magnetic memory cell, and
- wherein the cell is one of an in-plane type and a tunneling type of magnetic random access memory.
A low switching field multi-state, multi-layer magnetic memory cell comprising:
- a plurality of layers of magnetic material stacked in parallel, overlying relationship and separated by layers of non-magnetic material so as to form a multi-layer magnetic memory cell having a length and a width;
- the width of the multi-layer magnetic memory cell being less than the length and less than a width of magnetic domain walls within the layers of magnetic material setting a shape anisotropy easy axis along the length of the multi-layer magnetic memory cell;
- and
- at least one of the plurality of layers of magnetic material having an easy axis magnetic anisotropy generally parallel to the width of the multi-layer magnetic memory cell, and
- wherein the cell is formed with a shape anisotropy generally described by the expression K.sub.D sin.sup.2 .theta. and a magnetic anisotropy generally described by the expression -K.sub.m sin.sup.2 .theta., where K.sub.m is a magnetic anisotropy energy density, K.sub.D is a demagnetization energy density, .theta. is an angle between the shape anisotropy easy axis and the magnetization vector.
Dependencies are inferred from the claim text.