Magneto Resistive Element In-Plane Current Writing
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Solution Overview
Problem
The existing magneto resistive elements face reliability issues due to damage of the non-magnetic layer during writing operations using spin-transfer torque, which shortens their lifespan and degrades their performance.
Innovation Solution
A magneto resistive element design featuring a laminate structure with a first and second ferromagnetic layer and a non-magnetic layer, where the first and second conductive layers are connected to the surfaces of the laminate, allowing for a concentrated writing current that reduces damage to the non-magnetic layer and enhances writing efficiency by applying both spin-transfer torque and spin-orbit torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a writing current flows in the lamination direction of the laminate for data writing, then the writing operation can be performed, but the non-magnetic layer is damaged which shortens the lifespan and degrades reliability
Solution Approach 1:
The patent changes the flow direction of the writing current from the lamination direction (vertical) to an in-plane direction (horizontal), which is a dimensional change. This allows the current to flow along the plane of the laminate rather than through the layers, avoiding damage to the non-magnetic layer while still achieving magnetization reversal through spin-orbit torque effects.
Solution Approach 2:
The patent changes the parameter of current flow direction from vertical (through layers) to horizontal (in-plane). This parameter change enables the use of spin-orbit torque mechanisms that act on the magnetization without requiring high current densities that would damage the non-magnetic tunnel barrier layer.
2Ease of operation
If the non-magnetic layer is damaged during writing operations, then writing can be performed, but the lifespan is shortened and reliability is degraded
Solution Approach 1:
The patent changes the flow direction of the writing current from the lamination direction (vertical) to an in-plane direction (horizontal), which is a dimensional change. This allows the current to flow along the plane of the laminate rather than through the layers, avoiding damage to the non-magnetic layer while still achieving magnetization reversal through spin-orbit torque effects.
3Productivity
If high current density is applied for writing, then writing efficiency is improved, but damage to the non-magnetic layer increases
Solution Approach 1:
The patent changes the flow direction of the writing current from the lamination direction (vertical) to an in-plane direction (horizontal), which is a dimensional change. This allows the current to flow along the plane of the laminate rather than through the layers, avoiding damage to the non-magnetic layer while still achieving magnetization reversal through spin-orbit torque effects.
Solution Approach 2:
The patent substitutes the spin-transfer torque mechanism (which requires high current density flowing through the tunnel barrier) with a spin-orbit torque mechanism. This is achieved by introducing a ferromagnetic layer with perpendicular magnetic anisotropy and applying current in the in-plane direction, replacing the direct vertical current path with a horizontal current path that generates spin-orbit torque through the spin Hall effect or Rashba effect.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design achieves high writing efficiency with reduced current density, allowing for reliable data storage and extended lifespan of the magneto resistive elements by concentrating the writing current and applying both spin-transfer and spin-orbit torques.
Implementation Method 1
a method for performing writing utilizing a spin-transfer torque (STT) as disclosed in Japanese Unexamined Patent Application, First Publication No. 2021-103771
Implementation Method 2
a method for performing writing utilizing a spin-orbit torque (SOT) as disclosed in United States Patent Application, Publication No. 2014/0264513
Implementation Method 3
Magneto resistive elements are elements of which a resistance value in a lamination direction changes due to a magnetic resistance effect
Data Source
AI summary
A magneto resistive element includes a laminate that includes a first ferromagnetic layer, a second ferromagnetic layer, and a non-magnetic layer located between the first ferromagnetic layer and the second ferromagnetic layer; a first conductive layer that is connected to a first surface of the laminate in a lamination direction; and a second conductive layer that is connected to a second surface opposite the first surface. The first surface of the laminate includes a first region which comes into contact with the first conductive layer and a second region which does not come into contact with the first conductive layer.