Magnetoresistive Sensor Non-Magnetic Conducting Layer Shielding
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Solution Overview
Problem
Conventional magnetoresistive (MR) sensors face efficiency and resolution issues due to signal field shunting and longitudinal bias field leakage, leading to unstable magnetization and reduced performance, especially as areal density increases.
Innovation Solution
Incorporating non-magnetic conducting layers between the shielding layers and the MR element, embedded within the shielding layers to maintain a narrower read gap and prevent signal and bias field shunting, while increasing the longitudinal bias field stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If magnetic shielding layers are placed close to the MR element to provide strong shielding, then shielding effectiveness is improved, but signal field shunting increases and reduces sensor efficiency
Solution Approach 1:
A non-magnetic conducting layer is introduced as an intermediary between the magnetic shielding layer and the MR element. This intermediate layer prevents direct magnetic interaction while allowing electrical connection, thereby blocking signal field shunting to the shielding layer and improving sensor efficiency without compromising shielding effectiveness.
2Reliability
If the distance between the MR element and shielding layers is increased to prevent signal field shunting, then sensor efficiency is improved, but the read gap increases and resolution power decreases
Solution Approach 1:
The non-magnetic conducting layer serves as a mediator that enables the MR element to be positioned closer to the shielding layer (maintaining narrow read gap for high resolution) while preventing signal field shunting (maintaining high sensor efficiency). The intermediate layer blocks the harmful magnetic coupling without requiring increased separation distance.
3Stability of the object's composition
If longitudinal bias field strength is increased to stabilize magnetization direction, then magnetization stability is improved, but bias field leakage to shielding layers increases and weakens the effective bias
Solution Approach 1:
The non-magnetic conducting layer acts as a barrier that prevents longitudinal bias field leakage to the magnetic shielding layers. By blocking the magnetic flux path to the shielding layer, it ensures that the full strength of the bias field is applied to the MR element, improving both magnetization stability and bias field effectiveness simultaneously.
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 enhances the resolution power and signal-to-noise ratio, stabilizes the magnetization direction, and increases the total sensor area, improving reading performance and reliability.
Implementation Method 1
a first shielding layer, a second shielding layer, a MR element and a pair of hard magnet layers sandwiched therebetween
Implementation Method 2
MR sensor is used as a kind of popular read sensor because of its better capability to read data from disk surface
Implementation Method 3
The hard magnet layers 603 provides a longitudinal bias field to the MR element 650 for stabilizing a free layer of the MR element 650
Implementation Method 4
The non-magnetic insulating layer 605 electrically insulates the first shielding layer 601 from the second shielding layer 602
Data Source
AI summary
A MR sensor comprises a first shielding layer, a second shielding layer, a MR element and a pair of hard magnet layers sandwiched therebetween, and a non-magnetic insulating layer formed at a side of the MR element far from an air bearing surface of a slider. The MR sensor further comprises a first non-magnetic conducting layer formed between the first shielding layer and the MR element, and the first non-magnetic conducting layer is embedded in the first shielding layer and kept separate from the ABS. The MR sensor of the invention can obtain a narrower read gap to increase the resolution power and improve the reading performance, and obtain a strong longitudinal bias field to stabilize the MR sensor so as to increase the total sensor area and, in turn, get an improved reliability and performance. The present invention also discloses a magnetic head, a HGA and a disk drive unit.