Magnetic Head Evaluation Device for Rise Time Measurement
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Solution Overview
Problem
Current methods for evaluating the characteristics of magnetic heads, particularly in terms of magnetization reversal and oscillation, are inadequate for determining the rise time of magnetic elements, which is crucial for improving recording density and efficiency in magnetic recording devices.
Innovation Solution
An evaluation method and device that supply alternating and direct currents to a magnetic head's coil and element, respectively, to detect the time required for a change in electrical resistance based on polarity reversal, allowing for the assessment of magnetization reversal and oscillation times using specific frequency components and circuit configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional evaluation methods are used for magnetic head characteristics, then the evaluation process is simple, but the measurement precision of rise time is insufficient
Solution Approach 1:
The evaluation device segments the measurement process into distinct functional modules: an AC signal supply unit for providing alternating current to the coil, a DC signal supply unit for providing direct current to the magnetic element, and a measurement unit for detecting resistance changes. This segmentation allows each module to be optimized for its specific function while maintaining overall system precision for rise time measurement.
Solution Approach 2:
The patent introduces an intermediary measurement approach by using electrical resistance change as a mediator to indirectly measure magnetization reversal time. Instead of directly measuring the magnetic property changes, the device measures the corresponding electrical resistance variation of the magnetic element, which provides more precise and detectable signals for rise time determination.
2Productivity
If conventional evaluation methods are used, then the device complexity is low, but the productivity of magnetic head evaluation is insufficient
Solution Approach 1:
The evaluation device enables continuous measurement by maintaining constant DC current flow through the magnetic element while superimposing AC signals on the coil. This continuous action allows for real-time detection of resistance changes throughout the magnetization reversal process, improving evaluation efficiency without requiring repeated discrete measurements.
Solution Approach 2:
The device employs periodic AC signal application to the coil at specific frequencies that resonate with or drive the magnetization reversal process. This periodic action creates repeatable, measurable resistance variations that enhance the speed and reliability of rise time detection, allowing for faster evaluation cycles.
3Measurement precision
If simple measurement methods are used, then the ease of operation is high, but the measurement precision of magnetization reversal time is insufficient
Solution Approach 1:
The measurement unit provides feedback by continuously monitoring the electrical resistance of the magnetic element and comparing it against reference values or expected patterns. This feedback mechanism automatically identifies the precise moment of magnetization reversal based on resistance change thresholds, achieving high measurement precision while reducing the need for complex manual analysis or interpretation by the operator.
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
Enables efficient evaluation of magnetic head characteristics, optimizing conditions for improved recording density and speed, thereby enhancing magnetic recording performance.
Implementation Method 1
supplying a first alternating current to a coil of a magnetic head
Implementation Method 2
detecting a time required for a change of an electrical resistance of the magnetic element
Data Source
AI summary
According to one embodiment, an evaluation method of a magnetic head is disclosed. The method can include acquiring an electrical signal obtained from a magnetic element when supplying a first alternating current to a coil of a magnetic head and supplying a second current to the magnetic element. The magnetic head includes a first magnetic pole, a second magnetic pole, and a coil. The magnetic element is provided between the first magnetic pole and the second magnetic pole, and includes a first magnetic layer. The method can include detecting a time required for a change of an electrical resistance of the magnetic element based on a time when a polarity of the first alternating current is reversed based on the electrical signal.