Magnetic Film With Pt Buffer Layer for FePt Vertical Magnetization
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Solution Overview
Problem
Conventional magnetic films using MgO substrates are prone to deformation due to water exposure, leading to instability in magnetic recording and increased manufacturing costs, while substrates like silicon or glass struggle to achieve vertical magnetization with FePt alloys, resulting in high material usage and costs.
Innovation Solution
A magnetic film with a platinum layer having a (001) plane orientation and island-shaped iron-platinum crystallites with a 50 atomic % composition, where the crystallites have a (001) plane orientation parallel to the platinum layer, and a platinum concentration gradient, allowing for efficient vertical magnetic anisotropy and reduced material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MgO substrate is used for magnetic film, then vertical magnetization can be achieved, but substrate deformation occurs due to water exposure leading to recording instability
Solution Approach 1:
A buffer layer is introduced between the MgO substrate and the FePt magnetic layer to prevent water from reaching the MgO substrate. This intermediary layer protects the substrate from water-induced deformation while preserving the vertical magnetization capability, thereby resolving the contradiction between achieving vertical magnetization and maintaining substrate dimensional stability.
Solution Approach 2:
The patent uses a thin buffer layer that can be easily deposited and removed if necessary. This disposable-like layer provides temporary protection against water exposure during the operational lifetime of the magnetic film, preventing substrate deformation without complicating the overall structure.
2Stability of the object's composition
If protective film is added to prevent water exposure, then substrate deformation is prevented, but manufacturing cost increases and recording head gap increases
Solution Approach 1:
The buffer layer serves multiple functions simultaneously: it acts as a water barrier to prevent substrate deformation, provides a suitable interface for FePt layer deposition, and maintains the vertical magnetic anisotropy. This multi-functionality eliminates the need for separate protective films, reducing manufacturing complexity and cost while preventing substrate deformation.
3Ease of manufacture
If silicon or glass substrate is used, then manufacturing cost is reduced, but vertical magnetization cannot be achieved with FePt alloy
Solution Approach 1:
The patent changes the crystallographic orientation parameter of the FePt layer by controlling it to grow with (001) orientation on the MgO substrate. This parameter change enables vertical magnetization on cost-effective substrates, resolving the contradiction between manufacturing cost and vertical magnetization capability.
4Reliability
If FePt crystalline amount is increased to ensure recording capacity, then recording density is maintained, but manufacturing cost increases
Solution Approach 1:
The patent creates local quality enhancement at the interface between the buffer layer and FePt magnetic layer, where vertical magnetic anisotropy is maximized. This localized improvement in magnetic properties allows for reduced overall FePt material usage while maintaining recording capacity, resolving the contradiction between recording reliability and material quantity.
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 magnetic film achieves a high coercive force with reduced material requirements, lowering manufacturing costs and maintaining recording density stability, while allowing for efficient vertical magnetization without the need for excessive FePt crystalline material.
Implementation Method 1
efficient vertical magnetic anisotropy and reduced material usage
Implementation Method 2
island-shaped iron-platinum crystallites with a 50 atomic % composition, where the crystallites have a (001) plane orientation parallel to the platinum layer
Data Source
AI summary
A magnetic film comprises a platinum layer having a (001) plane orientation and an island-shaped iron-platinum crystalline arranged on the platinum layer and having a (001) plane orientation parallel to the (001) plane orientation of the platinum layer, wherein the island-shaped iron-platinum crystalline has a composition region consisting of 50 atomic % of each of iron and platinum and exhibits a perpendicular magnetic anisotropy having a high coercive force in a direction perpendicular to the surface of the platinum layer.