Magnetic Storage Write Head Nanoparticle Core-Shell Structure
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Solution Overview
Problem
The fundamental limit of data storage density in magnetic data storage devices is reached due to the superparamagnetic limit, where nanoparticles below a critical size cannot maintain permanent magnetization, and reducing their size further increases read-back noise or requires higher anisotropy and write fields, which are already maximized.
Innovation Solution
A write head with a magnetic structure comprising a matrix material and embedded magnetic nanoparticles, where each nanoparticle has a core covered with a shell layer of different material, reducing core contact and allowing higher nanoparticle volume fractions without agglomeration, thereby enhancing magnetic moment and storage density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If smaller magnetic nanoparticles are used to increase storage density, then storage capacity improves, but the nanoparticles become superparamagnetic and cannot maintain permanent magnetization
Solution Approach 1:
The patent uses composite materials by combining magnetic nanoparticles with a matrix material to form a magnetic structure. The matrix material provides structural support and stability, allowing the use of smaller magnetic particles without losing magnetization stability. This composite approach enables higher storage density while maintaining permanent magnetization.
2Quantity of substance
If higher nanoparticle volume fractions are used to increase storage density, then storage capacity improves, but nanoparticle agglomeration occurs reducing performance
Solution Approach 1:
The matrix material acts as an intermediary between magnetic nanoparticles, preventing direct contact and agglomeration. This intermediary substance allows higher nanoparticle volume fractions to be packed without the particles clumping together, maintaining both high storage density and uniform distribution.
3Stability of the object's composition
If higher anisotropy magnetic materials are used to maintain magnetization at smaller sizes, then magnetization stability improves, but higher write fields are required which are already maximized
Solution Approach 1:
The patent changes the physical parameters of the magnetic system by using the matrix material to modify the effective anisotropy and magnetic properties of the nanoparticle ensemble. This allows achieving magnetization stability without requiring individual particles to have extremely high anisotropy, thereby avoiding the need for excessively high write fields.
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 enables the use of smaller magnetic nanoparticles with higher anisotropy, increasing data storage capacity and overcoming the superparamagnetic limit by enhancing the magnetic field strength, thus improving storage density beyond current limitations.
Implementation Method 1
a write head operable to generate a magnetic field that impinges on a selected portion of the magnetic material of the data storage medium adjacent the write head, so as to affect the magnetisation direction
Implementation Method 2
the shell layers of the nanoparticles substantially prevent contact between cores of adjacent nanoparticles
Implementation Method 3
allowing higher nanoparticle volume fractions without agglomeration, thereby enhancing magnetic moment and storage density
Data Source
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AI summary
The present invention relates to an electromagnetic data storage device comprising a data storage medium including a magnetic material, and a write head including an electromagnetic element operable to generate a magnetic field that impinges on a selected portion of the magnetic material of the data storage medium adjacent the write head, so as to affect the magnetisation direction of the selected portion of magnetic material. The electromagnetic element includes a magnetic structure including a matrix material, and a plurality of magnetic nanoparticles held in the matrix material.