GdOX Tunnel Barrier MTJ Voltage-Controlled Coupling

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Solution Overview

Problem

Current magnetic tunnel junctions face challenges in achieving low-energy magnetization switching due to high switching energy, which leads to heating issues, and existing technologies struggle to control interlayer coupling efficiently without external magnetic fields.

Innovation Solution

The development of a magnetic tunnel junction (MTJ) system with a gadolinium oxide (GdOX) tunnel barrier, where voltage-controlled interlayer coupling is achieved by manipulating the oxygen vacancies within the barrier, allowing for reversible and deterministic switching between antiferromagnetic and ferromagnetic coupling states at room temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional magnetic field or current-induced torque methods are used to switch nanomagnet orientations, then magnetization switching can be achieved, but switching energy is high causing heating issues

Engineering Contradiction:

Improveswitching energyVSAvoiddevice temperature

Core Design Contradiction:

Use of energy by moving objectVSTemperature

Solution Approach 1:

The patent replaces the conventional mechanical/physical switching mechanisms (magnetic fields and current-induced spin transfer torques) with an electric field-based mechanism. By applying voltage across the tunnel barrier, the electric field directly modulates the interlayer coupling strength, enabling magnetization switching with significantly reduced energy dissipation and minimal heating.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the control parameter from magnetic field strength or current magnitude to voltage magnitude. By varying the applied voltage, the interlayer coupling transitions between ferromagnetic and antiferromagnetic states, providing a continuous parameter control mechanism that reduces switching energy requirements.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If external magnetic fields are used to control interlayer coupling, then coupling states can be switched, but device complexity and control difficulty increase

Engineering Contradiction:

Improveinterlayer coupling controlVSAvoidcontrol mechanism complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent substitutes external magnetic field control with electrical voltage control. The electric field applied across the tunnel barrier provides direct control over interlayer coupling strength and sign, eliminating the need for complex magnetic field generation systems and simplifying the overall device architecture.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The tunnel barrier serves as an intermediary medium that transduces the applied electric field into interlayer coupling modulation. This intermediary mechanism allows voltage control to effectively regulate the magnetic interaction between layers without requiring direct magnetic field application.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach significantly reduces switching energy, enabling efficient magnetization switching with voltage-controlled interlayer coupling, achieving large perpendicular magnetic anisotropy and sizable tunneling magnetoresistance, and allowing for low-power operation and integration with CMOS technologies.

Implementation Method 1

voltage-controlled interlayer coupling is achieved by manipulating the oxygen vacancies within the barrier, allowing for reversible and deterministic switching between antiferromagnetic and ferromagnetic coupling states

Methodology Applied

Scientific EffectVoltage-controlled interlayer coupling:

Implementation Method 2

achieving large perpendicular magnetic anisotropy and sizable tunneling magnetoresistance

Methodology Applied

Scientific EffectTunneling magnetoresistance: Magnetoresistance

Implementation Method 3

achieving large perpendicular magnetic anisotropy

Methodology Applied

Scientific EffectPerpendicular magnetic anisotropy: Anisotropy

Data Source

PatentUS11805703B2Magnetic tunnel junctions with voltage tunable interlayer coupling for memory and sensor applications

Publication Date: 2023.10.31 THE ARIZONA BOARD OF REGENTS ON BEHALF OF THE UNIV OF ARIZONA

AI summary

Various examples are provided for magnetic tunnel junctions and applications thereof. In one example, a magnetic tunnel junction (MTJ) device includes a first ferromagnetic (FM) layer; a gadolinium oxide (GdOX) tunnel barrier disposed on the first ferromagnetic layer; and a second FM layer disposed on the GdOX tunnel barrier. In another example, a perpendicular MTJ (pMTJ) device includes a first layer including a magnetic material; a tunnel barrier disposed on the first layer to form the pMTJ; and a second layer including the magnetic material, the second layer disposed on the tunnel barrier.