Half Heusler Alloy Topological Semimetal Spin Injection Source
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Solution Overview
Problem
Existing spin transfer torque (STT) magnetic memory devices require large currents for magnetization control, leading to device deterioration, while spin orbit torque (SOT) methods face challenges with spin Hall material properties such as low electric conductivity and limited spin Hall angle.
Innovation Solution
The use of a half Heusler alloy-topological semi-metal (HHA-TSM) like YPtBi as a spin injection source, which has a high electric conductivity exceeding 10^5 S/m and a spin Hall angle greater than 1, reducing the current required for magnetization control and improving device efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spin transfer torque (STT) method is used to control magnetization, then magnetization control is achieved, but large current is required causing device deterioration
Solution Approach 1:
The patent introduces a spin injection source layer as an intermediary component that generates spin-polarized current through the spin Hall effect. This mediator layer converts charge current to spin current more efficiently, reducing the direct current burden on the magnetization control process and thereby extending device durability while maintaining effective magnetization switching.
Solution Approach 2:
The patent changes the material parameters of the spin injection source, specifically selecting materials with high spin Hall angles and optimizing thickness parameters. By adjusting these physical parameters, the spin current generation efficiency is enhanced, which reduces the required current for magnetization control and decreases device stress and deterioration.
2Power
If conventional spin Hall materials are used, then spin current generation is achieved, but electric conductivity is low and spin Hall angle is limited
Solution Approach 1:
The patent employs composite material structures combining different metallic layers with complementary properties. The spin injection source is constructed using composite materials that integrate high spin Hall angle materials with high conductivity materials, achieving both efficient spin current generation and low electrical resistance, thereby simultaneously improving power efficiency and reliability.
Solution Approach 2:
The patent applies local quality optimization by assigning different material properties to different regions of the spin injection source. The structure incorporates materials with locally optimized characteristics - high spin Hall angle in specific layers for efficient spin current generation, and high conductivity materials in current transport regions - achieving both goals through spatially differentiated material properties.
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
The HHA-TSM-based spin injection source significantly reduces power consumption for magnetization reversal in magnetic memory devices, enhances spin current generation efficiency, and improves affinity for semiconductor manufacturing processes.
Implementation Method 1
The SHE is a phenomenon in which a spin current is generated in a direction perpendicular to a current injected into a nonmagnetic material. As a material having a strong SHE, a heavy metal and a topological insulator, in which a spin orbit interaction is strong, are known.
Data Source
AI summary
According to one embodiment, a spin injection source comprising a half Heusler alloy-topological semi-metal that has a surface state of Dirac type and that is in contact with a ferromagnet. The half Heusler alloy-topological semi-metal supplies a spin current to the ferromagnet based on a current flowing in a direction parallel to a first surface that is in contact with the ferromagnet.