US 9,006,704 B2 · Magnetic element with improved out-of-plane anisotropy for spintronic applications

Abstract

A magnetic element is disclosed wherein first and second interfaces of a free layer with a Hk enhancing layer and tunnel barrier, respectively, produce enhanced surface perpendicular anisotropy to lower switching current or increase thermal stability in a magnetic tunnel junction (MTJ). In a MTJ with a bottom spin valve configuration where the Hk enhancing layer is an oxide, the capping layer contacting the Hk enhancing layer is selected to have a free energy of oxide formation substantially greater than that of the oxide. The free layer may be a single layer or composite comprised of an Fe rich alloy such as Co20Fe60B20. With a thin free layer, the interfacial perpendicular anisotropy may dominate the shape anisotropy to generate a magnetization perpendicular to the planes of the layers. The magnetic element may be part of a spintronic device or serve as a propagation medium in a domain wall motion device.

Claims21

Dependent claims

A magnetic element exhibiting interfacial perpendicular anisotropy at first and second interfaces of a free layer with certain adjoining layers, comprising:

(a) a pinned layer formed on a substrate;
(b) a tunnel barrier layer that adjoins a surface of the pinned layer;
(c) the free layer having a bottom surface which forms a first interface with a surface of the tunnel barrier that faces away from the pinned layer, and having a top surface that forms a second interface with a Hk enhancing layer, the free layer is a composite of two CoFeB magnetic layers wherein a Fe content in a first CoFeB magnetic layer is different from a Fe content in a second CoFeB magnetic layer and has perpendicular magnetic anisotropy (PMA);
(d) the Hk enhancing layer that provides interfacial surface anisotropy in the free layer along the second interface such that interfacial perpendicular anisotropy at the first and second interfaces dominates a shape anisotropy field within the free layer;
and
(e) a capping layer that adjoins a top surface of the Hk enhancing layer to give a stack of layers with a pinned layer/tunnel barrier/free layer/Hk enhancing layer/capping layer configuration.

3 more elements

Dependencies are inferred from the claim text.

Magnetic element with improved out-of-plane anisotropy for spintronic applications

Life of this patent

Magnetic element with improved out-of-plane anisotropy for spintronic applications

Life of this patent

Abstract

Claims21