Alumina-Textured Magnetic Recording Medium for Low-Friction Stability
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Solution Overview
Problem
Magnetic recording media used in data centers face issues with deteriorating travelling stability and increased friction, leading to servo signal errors and stick-slip phenomena, which affect electromagnetic conversion characteristics.
Innovation Solution
A magnetic recording medium with a specific layer structure, including a magnetic layer and a base layer, where the magnetic layer incorporates alumina particles with controlled surface roughness, arithmetic average roughness, power spectrum density, and protrusion height, resulting in a smooth surface and reduced friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the total thickness of the magnetic recording medium is reduced to increase recording capacity, then the length per cartridge increases and recording capacity improves, but the surface condition changes during repeated recording/reproduction and travelling stability deteriorates
Solution Approach 1:
The invention changes the surface roughness parameters of the magnetic recording medium to resolve the contradiction. Specifically, it controls the arithmetic average roughness Ra to be 0.3 nm or less and the maximum height of protrusions to be 1.5 nm or less, which maintains surface smoothness even in thin media, preventing deterioration during repeated use while enabling high recording capacity
Solution Approach 2:
The invention uses a composite structure with a base layer and a magnetic layer containing specific particles (such as γ-Fe2O3, Co, Ni, or their alloys) dispersed in a binder resin. This composite material design allows the magnetic layer to maintain structural integrity and surface smoothness despite reduced overall thickness, thereby maintaining travelling stability while increasing recording capacity
2Productivity
If data tracks are narrowed to increase capacity, then recording density improves, but servo signals are erroneously read due to increased friction
Solution Approach 1:
The invention changes the surface roughness parameters to maintain smooth surfaces that reduce friction. By controlling Ra to 0.3 nm or less and maximum protrusion height to 1.5 nm or less, the friction between the magnetic head and medium is reduced, preventing stick-slip phenomena that would cause servo signal errors, thereby enabling reliable reading even with narrowed data tracks
3Reliability
If the surface is made smooth to improve electromagnetic conversion characteristics, then electromagnetic conversion characteristics improve, but friction may increase during travelling
Solution Approach 1:
The invention optimizes surface roughness parameters to simultaneously improve electromagnetic conversion characteristics and control friction. By setting Ra to 0.3 nm or less and maximum protrusion height to 1.5 nm or less, the surface is sufficiently smooth for good electromagnetic coupling while preventing excessive friction that would cause stick-slip phenomena during travelling
Data Source
AI summary
It is a main object to provide a magnetic recording medium having excellent electromagnetic conversion characteristics.The present technology provides a magnetic recording medium having a layer structure, including: a magnetic layer and a base layer, in which the magnetic layer includes an alumina particle, a surface roughness Rab (a measurement range: 236 μm×177 μm) is 1.70 nm or less, an arithmetic average roughness Ra (a measurement range: 40 μm×40 μm) is 1.79 nm or less, or a power spectrum density (PSD) value at a spatial wavelength of 5 μm or less is 3.77 nm2 or less, and an average height of a protrusion formed by the alumina particle is 0.0067 μm or less.