Lateral Spin Valve Reader with Large-Area Spin Injector
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Solution Overview
Problem
Magnetic data storage devices face challenges in increasing data density due to limitations in reducing the size and spacing of magnetic bits, which restricts the miniaturization of read sensors like GMR or TMR sensors sandwiched between magnetic shields.
Innovation Solution
The lateral spin valve reader design includes a channel layer with a spin injector and detector, featuring a large-area spin injector to increase spin-polarized current and decrease junction resistance, allowing for reduced shield spacing and enhanced bit detection signal amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional GMR or TMR sensors are sandwiched between magnetic shields to increase data density, then data storage capacity increases, but the spacing between shields cannot be reduced further due to sensor structure limitations
Solution Approach 1:
The patent transitions from a vertical sensor stack configuration to a lateral spin valve configuration where the spin injection structure and detector are positioned laterally at opposite ends of a channel layer. This dimensional change allows for reduced shield spacing while maintaining sensor functionality, as the lateral arrangement eliminates the need for thick vertical stacks between shields.
Solution Approach 2:
The patent changes the operational parameters by using spin-polarized current injection through a large-area spin injection structure, which fundamentally alters how the sensor operates compared to traditional TMR sensors. This parameter change enables the sensor to function with reduced dimensions and smaller shield spacing.
2Quantity of substance
If sensor size is decreased to increase data density, then more bits can be stored, but the amplitude of bit detection signal decreases
Solution Approach 1:
The patent merges the spin injection function with a large-area structure, combining the benefits of size reduction with enhanced signal amplitude. The large-area spin injection structure provides both the miniaturization needed for high density and the increased signal amplitude needed for precise detection.
Solution Approach 2:
The patent employs a composite structure consisting of a channel layer with specific spin-dependent scattering properties, a large-area spin injection structure, and a detector structure. This composite arrangement enables simultaneous achievement of small sensor footprint and large detection signal amplitude.
3Quantity of substance
If shield spacing is reduced to increase data density, then storage capacity increases, but total reader resistance increases
Solution Approach 1:
The patent changes the electrical parameters by implementing a lateral spin valve configuration with a large-area spin injection structure, which reduces the total reader resistance compared to traditional vertical configurations. This parameter change allows for reduced shield spacing without the penalty of excessive resistance.
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 design effectively decreases total reader resistance and increases the amplitude of the bit detection signal, enabling higher data density and efficient magnetic data storage by leveraging spin-polarized current and minimizing junction resistance.
Implementation Method 1
spin-dependent scattering in the channel layer
Implementation Method 2
a magnetoresistive (MR) sensor such as a Giant Magnetoresistive (GMR) sensor or a Tunnel Junction Magnetoresistive (TMR) sensor has traditionally been employed as the read transducer to read a magnetic signal from the magnetic media. The MR sensor has an electrical resistance that changes in response to an external magnetic field.
Data Source
AI summary
A lateral spin valve reader includes a channel layer having a first end that is proximate to a bearing surface and a second end that is away from the bearing surface. The lateral spin valve reader also includes a detector structure disposed over an upper surface of a first portion of the channel layer that is proximate to the first end of the channel layer. A spin injection structure disposed below a lower surface of a second portion of the channel layer is proximate to the second end of the channel layer. An area of overlap between the spin injection structure and the second portion of the channel layer is substantially larger than an area of overlap between the detector structure and the first portion of the channel layer.