HDD Magnetic Head Shields With (100) Texture for Low Hc and High Bs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic heads in hard disk drives (HDDs) face a challenge in achieving high saturated magnetic flux density (Bs) while maintaining low magnetic coercivity (Hc) to prevent early magnetic saturation, which is typically addressed by using materials with high Bs and low Hc, but these materials suffer from undesirable magnetic saturation issues.
Innovation Solution
The use of a textured layer to induce nucleation and growth of body-centered cubic (BCC) ferromagnetic materials with high Bs and low Hc, achieved through a structure comprising an amorphous layer, a (100) orientation enabling layer, and a texture transfer layer to disrupt underlying crystal seeding effects and ensure a (100) orientation, thereby enhancing magnetic moment and reducing magnetic saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If materials with high saturated magnetic flux density (Bs) and low magnetic coercivity (Hc) are used in shields, then reading and writing accuracy is improved, but magnetic saturation occurs earlier due to low magnetic moments
Solution Approach 1:
The patent changes the crystallographic orientation parameter from random or (110) to (100) orientation in the ferromagnetic shield layers. This parameter change results in increased magnetic moment and reduced magnetic saturation, while maintaining the desired low Hc and high Bs properties for improved reading and writing accuracy.
Solution Approach 2:
The patent employs composite material structures combining specific ferromagnetic materials (such as CoFe, FeCo) with carefully designed buffer layers and texture transfer layers. This composite approach enables the achievement of (100) orientation and optimizes the balance between magnetic moment, coercivity, and saturated flux density to prevent early saturation while maintaining high accuracy.
2Reliability
If low magnetic coercivity (Hc) is achieved through material selection, then magnetic saturation is prevented, but the magnetic moment remains insufficient for optimal performance
Solution Approach 1:
The patent utilizes parameter changes in crystallographic orientation, specifically transitioning to (100) orientation, which fundamentally alters the magnetic properties to increase magnetic moment while maintaining low Hc. This resolves the contradiction by changing the orientation parameter rather than simply adjusting material composition.
Solution Approach 2:
The patent replaces conventional material composition adjustments with a texture-induced mechanism where (100) orientation enabling layers and texture transfer layers create specific crystallographic orientations. This substitution of approach increases magnetic moment through orientation control rather than relying solely on material selection.
3Reliability
If textured layers are introduced to induce (100) orientation and increase magnetic moment, then magnetic saturation is minimized, but device structure becomes more complex
Solution Approach 1:
The patent segments the shield structure into distinct functional layers: (100) orientation enabling layers (such as RuAl, CrMo) and texture transfer layers (such as NiAl, IrAl, CoAl, RhAl, RuAl). This segmentation allows each layer to perform its specific function of orientation induction or transfer, achieving (100) orientation and increased magnetic moment while maintaining manageable structural complexity through modular design.
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 allows for increased magnetic moments in HDD shields and ferromagnetic layers, minimizing magnetic saturation while maintaining low coercivity, thus improving the performance and reliability of magnetic recording devices.
Implementation Method 1
A textured layer can be used to induce nucleation and growth of an interfacial nature such that body centered cubic (BCC) ferromagnetic materials with high Bs and low Hc are obtained
Implementation Method 2
a (100) orientation enabling layer disposed on the amorphous layer; and a texture transfer layer configured to transfer a (100) orientation to a layer disposed thereon
Data Source
AI summary
Magnetic moments can be increased in hard disk drive (HDD) shields and ferromagnetic layers to minimize magnetic saturation while still maintaining low magnetic coercivity (Hc) and high saturated magnetic flux (Bs). A textured layer can be used to induce nucleation and growth of an interfacial nature such that body centered cubic (BCC) ferromagnetic materials with high Bs and low Hc are obtained while also increasing the magnetic moment. The textured layer will cause the ferromagnetic material to grow with low Hc regardless of the crystallographic orientation.