Spin hall effect magnetic structures

Abstract

An article may include a substantially perpendicularly magnetized free layer having a first magnetic orientation in the absence of an applied magnetic field. The article may also include a spin Hall channel layer configured to conduct a spin current configured to subject the perpendicularly magnetized free layer to a magnetic switching torque and a substantially in-plane magnetized bias layer configured to bias the substantially perpendicularly magnetized free layer to a second magnetic orientation. The second magnetic orientation is different than the first magnetic orientation and is out of a plane of the substantially perpendicularly magnetized free layer.

What is claimed is: 
     
         1 . An article comprising:
 a substantially perpendicularly magnetized free layer having a first magnetic orientation in the absence of an applied magnetic field;   a spin Hall channel layer configured to generate a spin current configured to subject the perpendicularly magnetized free layer to a magnetic switching torque; and   a substantially in-plane magnetized bias layer configured to bias the substantially perpendicularly magnetized free layer to a second magnetic orientation that is different than the first magnetic orientation, wherein the second magnetic orientation is out of a plane of the substantially perpendicularly magnetized free layer.   
     
     
         2 . The article of  claim 1 , wherein the substantially perpendicularly magnetized free layer is disposed between the substantially in-plane magnetized bias layer and the spin Hall channel layer and is dipole-coupled to the substantially in-plane magnetized bias layer. 
     
     
         3 . The article of  claim 1 , wherein the substantially perpendicularly magnetized free layer is disposed adjacent the spin Hall channel layer. 
     
     
         4 . The article of  claim 1 , wherein the substantially in-plane magnetized bias layer is disposed between the substantially perpendicularly magnetized free layer and the spin Hall channel layer. 
     
     
         5 . The article of  claim 4 , further comprising a spacer layer between the substantially perpendicularly magnetized free layer and the substantially in-plane magnetized bias layer, wherein the spacer layer has a predetermined thickness to control exchange coupling between the substantially perpendicularly magnetized free layer and the substantially in-plane magnetized bias layer. 
     
     
         6 . The article of  claim 4 , wherein the substantially in-plane magnetized bias layer is disposed adjacent the spin Hall channel layer. 
     
     
         7 . The article of  claim 4 , wherein the spacer layer comprises a material that exhibits spin current polarization. 
     
     
         8 . The article of  claim 1 , further comprising a substantially perpendicularly magnetized pinned layer and an insulating barrier layer between the substantially perpendicularly magnetized pinned layer and the substantially perpendicularly magnetized free layer. 
     
     
         9 . An article comprising:
 an anisotropically graded free magnetic layer; and   a spin Hall channel layer configured to generate a spin current configured to modify the magnetic orientation of the anisotropically graded free magnetic layer.   
     
     
         10 . The article of  claim 9 , wherein the anisotropic graded magnetic layer exhibits a magnetic anisotropy gradient that varies from a substantially perpendicular magnetic anisotropy at a surface opposite the spin Hall channel layer to a non-perpendicular magnetic anisotropy at a surface adjacent to the spin Hall channel layer. 
     
     
         11 . The article of  claim 9 , wherein the anisotropic graded magnetic layer comprises at least one of a Heusler alloy, Fe x Pt 1-x , or Fe x Pd 1-x , wherein x is between about 0.4 and about 0.7. 
     
     
         12 . The article of  claim 9 , further comprising a substantially perpendicularly magnetized pinned layer and an insulating barrier layer between the substantially perpendicularly magnetized pinned layer and the anisotropically graded free magnetic layer. 
     
     
         13 . A method comprising:
 biasing a substantially perpendicularly magnetized free layer from a first magnetic orientation to a second magnetic orientation that is different than the first magnetic orientation by exerting a stray magnetic field from a substantially in-plane magnetized bias layer on the substantially perpendicular magnetized free layer, wherein the second magnetic orientation is out of a plane of the substantially perpendicularly magnetized free layer, and wherein the substantially perpendicularly magnetized free layer has the first magnetic orientation in the absence of an applied magnetic field; and   generating a spin current through a spin Hall channel layer to subject the substantially perpendicularly magnetized free layer to a magnetic switching torque.   
     
     
         14 . The method of  claim 13 , wherein the substantially perpendicularly magnetized free layer is disposed between the substantially in-plane magnetized bias layer and the spin Hall channel layer and is dipole-coupled to the substantially in-plane magnetized bias layer. 
     
     
         15 . The method of  claim 13 , wherein the substantially in-plane magnetized bias layer is disposed between the perpendicularly magnetized layer and the spin Hall channel layer, and wherein a spacer layer having a predetermined thickness to facilitate exchange-spring coupling between the substantially perpendicularly magnetized free layer and the substantially in-plane magnetized bias layer is disposed between the substantially perpendicularly magnetized free layer and the substantially in-plane magnetized bias layer. 
     
     
         16 . The method of  claim 13 , further comprising switching the substantially perpendicularly magnetized free layer from the first magnetic orientation to the second magnetic orientation by generating the spin current. 
     
     
         17 . A method comprising:
 generating a spin current through a spin Hall channel layer disposed adjacent an anisotropically graded free magnetic layer, wherein the anisotropically graded magnetic layer exhibits a magnetic anisotropy gradient that varies from substantially perpendicular magnetic anisotropy at a surface opposite the spin Hall channel layer to non-perpendicular magnetic anisotropy at a surface adjacent to the spin Hall channel layer.   
     
     
         18 . The method of  claim 17 , further comprising switching the anisotropically graded free magnetic layer from a first magnetic configuration to a second magnetic configuration by generating the spin current. 
     
     
         19 . A method comprising:
 depositing a substantially perpendicularly magnetized free layer over a spin Hall channel layer;   depositing a spacer layer on the substantially perpendicularly magnetized free layer; and   depositing a substantially in-plane magnetized bias layer over the spacer layer, wherein the substantially perpendicularly magnetized free layer is dipole-coupled to the substantially in-plane magnetized bias layer, and wherein the substantially in-plane magnetized bias layer is configured to magnetically bias the substantially perpendicularly magnetized free layer.   
     
     
         20 . A method comprising:
 depositing a substantially in-plane magnetized bias layer over a spin Hall channel layer;   depositing a spacer layer on the substantially in-plane magnetized bias layer; and   depositing a substantially perpendicularly magnetized free layer on the spacer layer, wherein the spacer layer has a predetermined thickness to control a strength of exchange coupling between the substantially perpendicularly magnetized free layer and the substantially in-plane magnetized bias layer.