A magnetoresistance (MR) element includes a first stack portion comprising a first plurality of layers including a first spacer layer having a first thickness and a first material selected to result in the first stack portion having a first sensitivity to the applied magnetic field. The MR element also has a second stack portion comprising a second plurality of layers, including a second spacer layer having a second thickness to result in the second stack portion having a second sensitivity to the applied magnetic field. The first thickness may be different than the second thickness resulting in the first sensitivity being different than the second sensitivity.

A spin-transfer torque (STT) magnetoresistive memory device includes a first electrode, a second electrode, and a magnetic tunnel junction located between the first electrode and the second electrode. The magnetic tunnel junpction includes a reference layer having a fixed magnetization direction, a free layer stack, and a nonmagnetic tunnel barrier layer located between the reference layer and the free layer stack. The free layer stack has a total thickness of less than 2 nm, and contains in order, a proximal ferromagnetic layer located proximal to the nonmagnetic tunnel barrier layer, a first non-magnetic metal sub-monolayer, an intermediate ferromagnetic layer, a second non-magnetic metal sub-monolayer, and a distal ferromagnetic layer.

The present invention is directed to a magnetic memory element including a magnetic free layer structure incorporating three magnetic free layers separated by two perpendicular enhancement layers (PELs) and having a variable magnetization direction substantially perpendicular to layer planes thereof; an insulating tunnel junction layer formed adjacent to the magnetic free layer structure; a first magnetic reference layer formed adjacent to the insulating tunnel junction layer opposite the magnetic free layer structure; a second magnetic reference layer separated from the first magnetic reference layer by a third perpendicular enhancement layer; an anti-ferromagnetic coupling layer formed adjacent to the second magnetic reference layer; and a magnetic fixed layer formed adjacent to the anti-ferromagnetic coupling layer. The first and second magnetic reference layers have a first invariable magnetization direction substantially perpendicular to layer planes thereof. The magnetic fixed layer has a second invariable magnetization direction substantially opposite to the first invariable magnetization direction.

A magnetic sensor whose output characteristic is less sensitive to the environmental temperature is provided. Magnetic sensor 1 has free layer 24 whose magnetization direction changes in response to an external magnetic field, pinned layer 22 whose magnetization direction is fixed with respect to the external magnetic field, spacer layer 23 that is located between pinned layer 22 and free layer 24 and that exhibits a magnetoresistance effect, and at least one magnet film 25 that is disposed on a lateral side of free layer 24 and that applies a bias magnetic field to free layer 24. A relationship of 0.7 ≤T.sub.C_HM/T.sub.C_FL≤1.05 is satisfied, where T.sub.C_HM is Curie temperature of the magnet film, and T.sub.C_FL is Curie temperature of the free layer.

A magnetic tunnel junction stack includes: a pinned layer; a main oxide barrier layer on the pinned layer; a free layer on the main oxide barrier layer; and a hybrid oxide/metal cap layer on the free layer. The hybrid oxide/metal cap layer includes: a first oxide layer on the free layer; a second oxide layer on the first oxide layer; and a metallic cap layer on the second oxide layer, wherein the free layer is free of boron (B).

A free layer comprising a bilayer (e.g., a first and a second layer) with an amorphous insertion layer in between the bilayer. The free layer includes a ferromagnetic nanolayer between the bilayer and a barrier layer. The magnetostriction of the free layer is tunable by varying the thicknesses of each of the first and the second layers. The free layer can be part of a magnetoresistive device with a reference layer or with another free layer.

A spin-transfer torque (STT) magnetoresistive memory device includes a first electrode, a second electrode, and a magnetic tunnel junction located between the first electrode and the second electrode. The magnetic tunnel junpction includes a reference layer having a fixed magnetization direction, a free layer stack, and a nonmagnetic tunnel barrier layer located between the reference layer and the free layer stack. The free layer stack has a total thickness of less than 2 nm, and contains in order, a proximal ferromagnetic layer located proximal to the nonmagnetic tunnel barrier layer, a first non-magnetic metal sub-monolayer, an intermediate ferromagnetic layer, a second non-magnetic metal sub-monolayer, and a distal ferromagnetic layer.

The present invention is directed to a magnetic memory element including a magnetic free layer structure incorporating three magnetic free layers separated by two perpendicular enhancement layers (PELs) and having a variable magnetization direction substantially perpendicular to layer planes thereof; an insulating tunnel junction layer formed adjacent to the magnetic free layer structure; a first magnetic reference layer formed adjacent to the insulating tunnel junction layer opposite the magnetic free layer structure; a second magnetic reference layer separated from the first magnetic reference layer by a third perpendicular enhancement layer; an anti-ferromagnetic coupling layer formed adjacent to the second magnetic reference layer; and a magnetic fixed layer formed adjacent to the anti-ferromagnetic coupling layer. The first and second magnetic reference layers have a first invariable magnetization direction substantially perpendicular to layer planes thereof. The magnetic fixed layer has a second invariable magnetization direction substantially opposite to the first invariable magnetization direction.

A magnetic tunnel junction is disclosed wherein the reference layer and free layer each comprise one layer having a boron content from 25 to 50 atomic %, and an adjoining second layer with a boron content from 1 to 20 atomic %. One of the first and second layers in each of the free layer and reference layer contacts the tunnel barrier. Each boron containing layer has a thickness of 1 to 10 Angstroms and may include one or more B layers and one or more Co, Fe, CoFe, or CoFeB layers. As a result, migration of non-magnetic metals along crystalline boundaries to the tunnel barrier is prevented, and the MTJ has a low defect count of around 10 ppm while maintaining an acceptable TMR ratio following annealing to temperatures of about 400 C. The boron containing layers are selected from CoB, FeB, CoFeB and alloys thereof including CoFeNiB.

Varying energy barriers of magnetic tunnel junctions (MTJs) in different magneto-resistive random access memory (MRAM) arrays in a semiconductor die to facilitate use of MRAM for different memory applications is disclosed. In one aspect, energy barriers of MTJs in different MRAM arrays are varied. The energy barrier of an MTJ affects its write performance as the amount of switching current required to switch the magnetic orientation of a free layer of the MTJ is a function of its energy barrier. Thus, by varying the energy barriers of the MTJs in different MRAM arrays in a semiconductor die, different MRAM arrays may be used for different types of memory provided in the semiconductor die while still achieving distinct performance specifications. The energy barrier of an MTJ can be varied by varying the materials, heights, widths, and/or other characteristics of MTJ stacks.