Orbital Hall Spin Current Generation With Minimal Heavy Metal
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Solution Overview
Problem
Current Spin Hall Effect devices rely heavily on heavy metals to generate spin current, which is undesirable and inefficient, as they seek to reduce the dependence on these metals by utilizing ordinary metals to produce spin current through the conversion of orbital current from the Orbital Hall Effect.
Innovation Solution
The conversion of out-of-plane orbital current from ordinary metals to spin current using thin layers of heavy metal, significantly reducing the amount of heavy metal required, as ordinary metals like Copper and Aluminum are used to generate orbital current, which is then converted into spin current via spin-orbital coupling in devices such as magnetoresistive sensors and magnetic tunnel junctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heavy metals are used to generate spin current through the Spin Hall Effect, then spin current generation efficiency is improved, but dependence on heavy metals increases and material cost increases
Solution Approach 1:
The device is segmented into distinct functional layers: an ordinary metal layer that generates orbital current via the Orbital Hall Effect, and a thin heavy metal layer that converts orbital current to spin current. This segmentation allows the bulk material to be ordinary metal while using minimal heavy metal only where needed for spin-orbit coupling, thereby reducing overall heavy metal dependence while maintaining spin current generation efficiency
Solution Approach 2:
The invention introduces orbital current as an intermediary between charge current and spin current. The ordinary metal layer converts charge current to orbital current through the Orbital Hall Effect, and this orbital current then serves as the intermediary that the thin heavy metal layer converts into spin current via spin-orbit coupling. This intermediary mechanism reduces the need for heavy metals in the charge-to-spin conversion process
2Reliability
If heavy metals are used to provide spin current, then spin-orbital coupling strength is improved, but material availability and cost are worsened
Solution Approach 1:
The heavy metal layer is applied locally only at the interface where spin-orbit coupling is required, rather than using heavy metals throughout the entire structure. This local quality approach concentrates the spin-orbital coupling function in a thin interfacial layer, maintaining strong coupling where needed while using abundant ordinary metals for the bulk structure, thereby improving material availability without sacrificing coupling strength
Solution Approach 2:
The device employs a composite structure combining ordinary metal and heavy metal layers, each performing its optimal function. The ordinary metal provides abundant charge carrier supply and orbital current generation, while the thin heavy metal layer provides the necessary spin-orbit coupling. This composite material approach leverages the strengths of both material classes while mitigating their individual weaknesses regarding availability and cost
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 substantially reduces the need for heavy metals while maintaining effective spin current generation, enabling efficient magnetic field sensing and data storage applications by utilizing ordinary metals to produce orbital current and converting it into spin current with minimal heavy metal usage.
Implementation Method 1
spin current is generated by conversion of out-of-plane orbital current arising from the Orbital Hall Effect (OHE) in ordinary metals
Implementation Method 2
The Spin Hall Effect (SHE) has been exploited for electrically-manipulating electron spin in a variety of spintronics applications. Spin current involves an alignment of intrinsic electron spin
Data Source
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AI summary
Devices for sensing and manipulating magnetic fields based on spin current interactions independent of the Spin Hall Effect (SHE) in heavy metal. Spin current is generated in ordinary metals by conversion of out-of-plane orbital current arising from the Orbital Hall Effect (OHE). The conversion from orbital current to spin current takes place in a thin layer of heavy metal (several atomic layers thick), thereby substantially reducing heavy metal requirements by replacing heavy metal with ordinary metal. Device applications include magnetoresistive sensors for detecting and measuring magnetic fields, and magnetic tunnel junction data storage units.