TMR Read Head Side Shields Using Nanocrystalline Particles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current tunnel magnetoresistance (TMR) read heads face challenges in reducing the difference between the lateral separation distance (MT50) and free layer track width (FLTW) to enhance interference immunity and signal-to-noise ratio, with state-of-the-art designs showing a difference of 6.5 nm or more.
Innovation Solution
Incorporating nanocrystalline ferromagnetic particles embedded in a non-magnetic dielectric material matrix as side shields within the TMR read head, which reduces the magnetic flux density and exchange interaction, thereby narrowing the MT50 and FLTW difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional side shields are used in TMR read heads, then the structure is simple and easy to manufacture, but the difference between MT50 and FLTW is large (6.5 nm or more), resulting in poor interference immunity and low signal-to-noise ratio
Solution Approach 1:
The side shields are constructed using composite materials consisting of nanocrystalline ferromagnetic particles (such as cobalt, iron, or their alloys) embedded in a non-magnetic dielectric matrix material. This composite structure reduces the magnetic flux density and exchange interaction, thereby narrowing the MT50 and FLTW difference to less than 6.5 nm, which improves interference immunity and signal-to-noise ratio while maintaining manufacturability
Solution Approach 2:
The side shields exhibit local quality variations through the distribution of nanocrystalline ferromagnetic particles within the non-magnetic dielectric matrix. This local magnetic property distribution allows for reduced magnetic flux density at critical locations, enabling better control of the magnetic field profile and achieving smaller MT50-FLTW difference without requiring complete structural redesign
2Reliability
If nanocrystalline ferromagnetic particles are used in side shields, then interference immunity and signal-to-noise ratio are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The invention changes the physical and chemical parameters of the side shield material by using nanocrystalline ferromagnetic particles with controlled size, shape, and distribution within the non-magnetic dielectric matrix. This parameter change reduces the magnetic flux density and exchange interaction, improving interference immunity and signal-to-noise ratio. The manufacturing complexity is managed through established deposition techniques such as sputtering or chemical vapor deposition that can control these parameters
3Reliability
If nanocrystalline ferromagnetic particles are used in side shields, then signal-to-noise ratio is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The invention changes the physical and chemical parameters of the side shield material by using nanocrystalline ferromagnetic particles with controlled size, shape, and distribution within the non-magnetic dielectric matrix. This parameter change reduces the magnetic flux density and exchange interaction, improving interference immunity and signal-to-noise ratio. The manufacturing complexity is managed through established deposition techniques such as sputtering or chemical vapor deposition that can control these parameters
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 use of nanocrystalline ferromagnetic particles in a non-magnetic dielectric matrix side shields in TMR read heads achieves a reduced MT50 and FLTW difference, improving interference immunity and signal-to-noise ratio, with MT50 greater than FLTW by less than 6.5 nm, enhancing reading performance.
Implementation Method 1
Incorporating nanocrystalline ferromagnetic particles embedded in a non-magnetic dielectric material matrix as side shields within the TMR read head, which reduces the magnetic flux density and exchange interaction
Implementation Method 2
Incorporating nanocrystalline ferromagnetic particles embedded in a non-magnetic dielectric material matrix as side shields within the TMR read head, which reduces the magnetic flux density and exchange interaction
Implementation Method 3
a tunnel magnetoresistance reading head including side shields containing nanocrystalline ferromagnetic particles
Data Source
AI summary
A tunnel magnetoresistance (TMR) read head includes a first magnetic shield, a read sensor stripe located over the first magnetic shield, a second magnetic shield located over the sensor layer stack, an electrical isolation dielectric layer located on sidewalls of the read sensor stripe, and a pair of side shields located on the electrical isolation dielectric layer between the first magnetic shield and the second magnetic shield. The read sensor stripe includes a sensor layer stack containing a pinned layer stack, a non-magnetic electrically insulating barrier layer, and a ferromagnetic free layer. The side shields include nanocrystalline ferromagnetic particles, such as Fe, Co or CoFe, embedded in a non-magnetic dielectric material matrix, such as hafnium oxide.