Magnetic Tape SFD Control for Thermal Stability

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Solution Overview

Problem

Magnetic recording media containing ε-iron oxide powder deteriorate in electromagnetic conversion characteristics when used under varying temperature conditions, such as room temperature and higher temperatures, necessitating a solution to maintain performance across different temperatures.

Innovation Solution

A magnetic recording medium with a non-magnetic support and a magnetic layer containing ε-iron oxide powder, where the vertical switching field distribution (SFD) is controlled between 0.20 and 3.00 at 25°C, and the inclination of SFD is between 0.003°C⁻¹ and 0.080°C⁻¹, incorporating elements like cobalt, gallium, or titanium to enhance stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If a magnetic recording medium containing ε-iron oxide powder is used under varying temperature conditions, then power consumption in data centers can be reduced by relaxing temperature control, but electromagnetic conversion characteristics deteriorate

Engineering Contradiction:
Improvepower consumptionVSAvoidelectromagnetic conversion characteristics
Core Design Contradiction:
Use of energy by stationary objectVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the vertical switching field distribution (SFD) to be 0.20 or more and 3.00 or less at 25°C, and controlling the inclination of SFD to be within 0.003°C⁻¹ to 0.080°C⁻¹. These parameter optimizations enable the magnetic recording medium to maintain stable electromagnetic conversion characteristics across temperature variations from 10°C to 40°C, allowing data centers to relax temperature control while preserving performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by incorporating ε-iron oxide powder with specific compositional characteristics into the magnetic layer. The ε-iron oxide powder contains iron and oxygen in specific ratios and may include substituent elements, creating a composite magnetic material that exhibits enhanced thermal stability and maintained electromagnetic conversion characteristics under varying temperature conditions

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If temperature control conditions are relaxed to save power, then operating costs decrease, but performance consistency across temperature conditions deteriorates

Engineering Contradiction:
Improvetemperature condition flexibilityVSAvoidperformance consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent optimizes parameters by controlling the vertical SFD within 0.20 to 3.00 at 25°C and the inclination of SFD within 0.003°C⁻¹ to 0.080°C⁻¹. These parameter settings enable the magnetic recording medium to adapt to temperature variations from 10°C to 40°C while maintaining consistent performance, achieving both temperature flexibility and performance reliability

Inventive Principle:
Principle #35Parameter changes

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 controlled SFD and inclination of SFD in the magnetic recording medium effectively suppress deterioration in electromagnetic conversion characteristics, ensuring consistent performance across different temperature conditions.

Implementation Method 1

a magnetic layer containing a ferromagnetic powder, in which the ferromagnetic powder is an ε-iron oxide powder

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 2

a vertical switching field distribution SFD of the magnetic recording medium is 0.20 or more and 3.00 or less at a measurement temperature of 25° C., and an inclination of SFD obtained from SFD at a measurement temperature of 10° C., SFD at a measurement temperature of 25° C., and SFD at a measurement temperature of 40° C. is 0.003° C.−1 or more and 0.080° C.−1 or less

Methodology Applied
Scientific EffectMagnetic hysteresis: Magnetic Hysteresis

Data Source

PatentUS11894032B2Magnetic recording medium having characterized vertical SFD, magnetic tape cartridge, and magnetic recording reproducing device
Publication Date: 2024.02.06 FUJIFILM CORP

AI summary

Provided are: a magnetic recording medium including a non-magnetic support and a magnetic layer containing a ferromagnetic powder, in which the ferromagnetic powder is an ε-iron oxide powder, a vertical switching field distribution SFD of the magnetic recording medium is 0.20 or more and 3.00 or less at a measurement temperature of 25° C., and an inclination of SFD obtained from SFD at a measurement temperature of 10° C., SFD at a measurement temperature of 25° C., and SFD at a measurement temperature of 40° C. is 0.003° C.−1 or more and 0.080° C.−1 or less; a magnetic tape cartridge including the magnetic recording medium which is a magnetic tape; and a magnetic recording and reproducing device including the magnetic recording medium.