Perovskite Spin-Orbit Torque Memory Devices

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Solution Overview

Problem

Current magnetic switching devices face challenges in achieving high spin-orbit torque efficiency at room temperature, particularly in using semiconductors, heavy metals, and topological insulators, which limits their applications in spintronics due to inefficient spin-orbit torque generation.

Innovation Solution

The development of magnetic switching devices utilizing single-crystalline films of epitaxially grown 4d or 5d transition metal perovskites with strong spin-orbit coupling, where a perpendicular spin-polarized current is generated in a layer of electrically conductive perovskite and directed into a ferromagnetic material, producing a spin-orbit torque that switches the magnetic moment efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional materials (semiconductors, heavy metals, topological insulators) are used for magnetic switching, then device structure is relatively simple, but spin-orbit torque generation efficiency is low

Engineering Contradiction:
Improvespin-orbit torque generation efficiencyVSAvoiddevice structure complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The invention employs a composite structure consisting of a ferromagnetic layer coupled with a perovskite layer containing 4d or 5d transition metal atoms. This composite material approach leverages the strong spin-orbit coupling inherent in 4d/5d transition metals to generate high spin-orbit torque efficiency, while the perovskite crystal structure provides a systematic framework for achieving this performance.

Inventive Principle:
Principle #40Composite materials

2Temperature

If room temperature operation is achieved, then device applicability is improved, but spin-orbit torque efficiency typically decreases

Engineering Contradiction:
Improveoperating temperatureVSAvoidspin-orbit torque efficiency
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The invention utilizes the unique electronic structure parameters of 4d and 5d transition metal atoms within the perovskite lattice, specifically their strong spin-orbit coupling characteristics. By selecting specific transition metals (Ru, Rh, Pd, Ag, Mo, Tc, Ru, Ir, Pt, Au) and controlling their oxidation states and local coordination environments, the material maintains high spin-orbit torque efficiency at room temperature through intrinsic electronic structure properties.

Inventive Principle:
Principle #35Parameter changes

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 enables high-efficiency spin-orbit torque generation even at room temperature, enhancing the performance of magnetic memory devices and logic applications by leveraging the spin-Hall effect in transition metal perovskites like SrIrO3, which demonstrates a large spin-torque ratio and efficient spin current transmission.

Implementation Method 1

passing a charge current through the layer of electrically conductive, epitaxial, single-crystalline 4d or 5d transition metal perovskite generates a perpendicular spin polarized current in the layer of electrically conductive, epitaxial, single-crystalline 4d or 5d transition metal perovskite and directed into the layer of ferromagnetic material, producing a spin-orbit torque

Methodology Applied
Scientific EffectSpin-Hall effect: Hall Effect

Data Source

PatentEP3646324B1Magnetic memory devices based on 4d and 5d transition metal perovskites
Publication Date: 2024.09.11 WISCONSIN ALUMNI RES FOUND
  • EP3646324B1 patent drawingFigure 1A
  • EP3646324B1 patent drawingFigure 1B~1C
  • EP3646324B1 patent drawingFigure 1D~1F

AI summary

Magnetic switching devices, including magnetic memory devices, are provided. The devices use high-quality crystalline films of 4d or 5d transition metal perovskite having a strong spinorbit coupling (SOC) to produce spin-orbit torque in adjacent ferromagnetic materials via a strong spin-Hall effect.