Magnetic Tunnel Junction Temperature Rise Measurement
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Solution Overview
Problem
Current methods cannot effectively measure the temperature rise induced by bias current/bias voltage in magnetic tunnel junctions (MTJ) of tunnel magnetoresistive (TMR) sensors, which is crucial for determining stable and reliable reading performance, especially at higher operational temperatures.
Innovation Solution
A method involving the application of an external time-changing magnetic field to measure outer pin flip field values under varying temperature and bias current/bias voltage conditions, calculating correlations to determine the temperature rise, utilizing the sensitivity of outer pin flip field to temperature and its independence from magneto-resistance ratio for accurate measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If higher bias current/bias voltage is applied to improve MR sensor performance, then reading performance is improved, but temperature rise increases inducing high temperature noise
Solution Approach 1:
The patent changes the measurement parameter from direct temperature measurement to outer pin flip field measurement. By measuring the outer pin flip field (which is sensitive to temperature) instead of directly measuring temperature, the system can indirectly determine temperature rise caused by bias current/voltage and adjust operating parameters accordingly to maintain reliable reading performance.
2Ease of manufacture
If conductor's method is used to measure temperature rise, then measurement is simple, but it cannot be implemented for TMR sensor
Solution Approach 1:
The patent introduces an intermediary measurement approach by using outer pin flip field as a mediator to indicate temperature. Instead of directly measuring temperature (which requires different methods for TMR sensors), the outer pin flip field serves as an intermediary parameter that reflects temperature changes and can be measured using magnetic field measurement techniques compatible with TMR sensors.
3Measurement precision
If outer pin flip field measurement is used, then temperature measurement accuracy is improved, but measurement complexity increases
Solution Approach 1:
The patent replaces direct thermal measurement mechanisms with magnetic field measurement mechanisms. By substituting the measurement approach from thermal sensing to magnetic field sensing (measuring outer pin flip field), the system achieves accurate temperature indication without requiring complex thermal measurement equipment, leveraging the existing magnetic measurement capabilities of TMR sensor systems.
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 the determination of stable and reliable reading performance in TMR sensors by quantifying the temperature rise induced by bias current/bias voltage, facilitating optimal reader design for higher operational temperatures.
Implementation Method 1
tunnel magnetoresistive (TMR) sensor, which includes a magnetic tunnel junction (MTJ) where the tunneling magneto-resistance effect (TMR effect) occurs
Implementation Method 2
measuring different first outer pin flip field values under different temperature values; calculating the correlation between the temperature and the outer pin flip field according to the temperature values and the first outer pin flip field values
Data Source
AI summary
A method for measuring a temperature rise induced by bias current/bias voltage in a magnetic tunnel junction includes: (a) applying an external time-changing magnetic field to the magnetic tunnel junction; (b) measuring different first outer pin flip field values under different temperature values; (c) correlating the temperature values with the outer pin flip field values; (d) measuring different second outer pin flip field values under different bias current/bias voltage values; (e) correlating the different bias current/bias voltage-values with the measured different second outer pin flip field values; and (f) correlating temperature values and bias current/bias voltage values according to the results produced by (c) and (e). The method can determine what kind of TMR reader design provides more stable and reliable reading performance, especially under higher operational temperatures.