CIP Spin Hall Sensor Layout for Higher Magnetic Signal Output
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Solution Overview
Problem
Existing SOT devices with current-perpendicular-to-plane (CPP) configurations suffer from canted spin currents, limiting the utilization of the full potential of large spin Hall angles, leading to inefficient signal output in magnetic sensors and read heads.
Innovation Solution
Implementing current-in-plane (CIP) spin orbit torque (SOT) devices with topological materials (TM) layers, such as BiSb or YPtBi, where current flows in-plane, enabling perpendicular spin currents and utilizing the full potential of large spin Hall angles for efficient spin-to-charge conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current-perpendicular-to-plane (CPP) SOT devices are used, then the device structure is simple, but the spin current becomes canted and the signal output is limited
Solution Approach 1:
The patent inverts the conventional current application direction from perpendicular-to-plane (CPP) to in-plane (CIP). By applying current in-plane to the topological material layer, the spin current is generated perpendicular to the magnetization direction without canting, fully utilizing the spin Hall effect to achieve saturated signal output while maintaining device simplicity
Solution Approach 2:
The patent changes the current direction parameter from perpendicular-to-plane to in-plane, and selects topological materials with large spin Hall angles (greater than 0.5) to maximize the spin Hall effect. This parameter change enables the spin current to align properly with the magnetization direction, eliminating canting and achieving full signal potential
2Use of energy by moving object
If topological materials with large spin Hall angles are used, then spin-to-charge conversion efficiency is improved, but device fabrication complexity increases
Solution Approach 1:
The patent employs composite material structures combining topological material layers (such as (BixSb1-x)2Te3 with x=0.2-0.4) with conventional magnetic tunnel junction layers. This composite approach leverages the large spin Hall angle of topological materials for efficient spin-to-charge conversion while using well-established fabrication processes for the remaining device structure, balancing performance improvement with manufacturing feasibility
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 CIP SOT devices achieve fast magnetic switching and improved signal output by fully utilizing the spin Hall angle, enhancing the efficiency of magnetic sensors and read heads.
Implementation Method 1
TM layers are narrow band gap topological insulators with both giant spin Hall effect and high surface electrical conductivity
Implementation Method 2
Current is configured to flow in-plane into the TM layer... enabling perpendicular spin currents and utilizing the full potential of large spin Hall angles
Data Source
AI summary
The present disclosure generally relates to a magnetic recording device comprising a current-in-plane (CIP) spin orbit torque (SOT) device. The SOT device comprises a topological material (TM) layer and one or more free layers. The TM layer may be recessed from the MFS, and may comprise BiSb or YPtBi. Current is configured to flow in-plane into the TM layer. In one embodiment, one or more free layers are disposed on a same surface of the TM layer. In another embodiment, one or more free layers are disposed on opposite surfaces of the TM layer. In embodiments, comprising two or more free layers, voltage outputs read from at least two of the two or more free layers are opposite, and the two free layers have opposite polarities. In another embodiment, the SOT device comprises four free layers arranged in a bridge configuration.