Magnetic Memory Device With Temperature-Dependent Saturation Magnetization
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Solution Overview
Problem
Magnetic memory devices face challenges in improving memory cell retention characteristics, particularly in preventing deterioration of the storage layer during standby states due to unnecessary bias magnetic fields.
Innovation Solution
The magnetic memory device incorporates a magnetic layer with a saturation magnetization that changes based on temperature, generating a leakage magnetic field only during write operations, thus avoiding unnecessary bias magnetic fields in standby or read states, and utilizing a spin orbit torque for writing data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a bias magnetic field is applied to assist write operations, then write operation efficiency is improved, but memory cell retention characteristics deteriorate due to unnecessary bias magnetic fields during standby states
Solution Approach 1:
The magnetic layer's saturation magnetization is made temperature-dependent, allowing it to dynamically change between a first value during standby/read states and a second value during write operations. This dynamic property enables the system to adapt its magnetic characteristics based on operational state, reducing harmful bias fields during standby while maintaining write efficiency.
Solution Approach 2:
The invention changes the saturation magnetization parameter of the magnetic layer based on temperature variations. During write operations, the temperature increases causing saturation magnetization to change from a first value to a second value, enabling efficient writing. During standby, the temperature returns to normal and saturation magnetization returns to the first value, preventing deterioration of retention characteristics.
2Reliability
If the magnetic layer has high saturation magnetization during standby state, then data retention is improved, but write operation load increases
Solution Approach 1:
The magnetic layer exhibits dynamic saturation magnetization that changes with temperature. During standby, it maintains high saturation magnetization (first value) for data retention. During write operations, temperature-induced changes reduce the saturation magnetization to a second value, lowering the write operation load required to switch magnetic states.
Solution Approach 2:
The saturation magnetization parameter is designed to change with temperature: maintaining a first value during standby for reliable data retention, and transitioning to a second value during write operations to reduce the energy and current required for magnetic switching, thereby reducing write operation load.
3Ease of operation
If the magnetic layer generates leakage magnetic field continuously, then write operation assistance is maintained, but device complexity increases to manage unnecessary bias fields
Solution Approach 1:
The magnetic layer automatically generates the required leakage magnetic field during write operations through temperature-induced changes in saturation magnetization, without requiring external control mechanisms. During standby states, the temperature returns to normal and the leakage magnetic field disappears naturally, eliminating the need for additional components to manage or suppress unnecessary bias fields.
Solution Approach 2:
The leakage magnetic field is generated on-demand through temperature-dependent parameter changes in the magnetic layer. During write operations, the temperature increase causes saturation magnetization to change, automatically generating the necessary leakage magnetic field for write assistance. During standby, the parameter returns to its original state and the leakage magnetic field vanishes without requiring additional device complexity for management.
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 configuration enhances data retention by preventing magnetic field-induced deterioration during standby and read operations while simplifying the device structure and reducing write operation load.
Implementation Method 1
a saturation magnetization that changes according to a temperature of the magnetic layer
Implementation Method 2
generating a leakage magnetic field only during write operations
Implementation Method 3
utilizing a spin orbit torque for writing data
Implementation Method 4
Magnetic memory devices using a magnetoresistance effect element as a storage element
Data Source
AI summary
A magnetic memory device includes first, second, and third conductor layers, and a memory cell that is coupled to the first, second, and third conductor layers. The memory cell includes a fourth conductor layer and a magnetoresistance effect element. The fourth conductor layer includes first, second, and third portions coupled to the first, second, and third conductor layers, respectively. The third portion is between the first and second portions. The magnetoresistance effect element is coupled between a third conductor and the fourth conductor layer. The fourth conductor layer includes a magnetic layer and a non-magnetic layer that is between the magnetic layer and the magnetoresistance effect element. The magnetic layer has a first saturation magnetization during a standby state or a read state of the memory cell, and has a second saturation magnetization larger than the first saturation magnetization during a write state of the memory cell.