Voltage-Controlled Magnetoelectric Logic Device for Low Power Computing
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Solution Overview
Problem
Existing magnetoelectric magnetic tunneling junction (MEMTJ) devices require multiple field effect transistors for operation, are sensitive to insulator thickness variability, and lack concatenability, leading to high power dissipation and reliability issues.
Innovation Solution
A stand-alone voltage-controlled magnetic device with a semiconductor configuration that eliminates the need for auxiliary FETs, includes an input electrode, antiferromagnetic layer, free magnets, and permanent magnets, allowing for concatenation and reduced static power dissipation by using electric fields to control magnetic fields and resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple field effect transistors are used to drive the next stage in existing MEMTJ devices, then the devices can perform logic functions, but the area, delay, and energy overheads increase significantly
Solution Approach 1:
The patent combines the logic function and the driving function into a single MEMTJ device. The magnetoelectric effect directly controls the resistance state, which naturally provides the driving capability for the next stage without requiring separate FETs. This merging eliminates the need for multiple auxiliary transistors, reducing area overhead while maintaining logic functionality.
Solution Approach 2:
The MEMTJ device is designed to perform multiple functions simultaneously: it acts as both the logic element and the driver for subsequent stages. The device's ability to switch between high and low resistance states under electric field control enables it to fulfill both computational and signal driving roles, eliminating the need for dedicated driver transistors.
2Productivity
If multiple field effect transistors are used to reset devices at the beginning of each clock cycle, then the devices can operate in sequence, but the static power dissipation increases
Solution Approach 1:
The MEMTJ device automatically resets its state through the magnetoelectric effect without requiring external reset circuits. The antiferromagnetic layer's magnetization can be switched by applying a voltage pulse, and the device naturally returns to a defined state, eliminating the need for continuous reset operations by auxiliary FETs that consume static power.
3Adaptability or versatility
If the output voltage is determined by voltage division between the FET and the MTJ, then the logic function can be achieved, but the device becomes very sensitive to insulator thickness variability
Solution Approach 1:
The patent replaces the voltage division mechanism (which depends on precise physical dimensions of insulators and FET characteristics) with a magnetoelectric control mechanism. The output state is determined by the magnetization direction controlled by electric field, not by passive voltage division, thereby eliminating sensitivity to insulator thickness variations.
4Adaptability or versatility
If current-driven magnetic devices are used, then the logic functions can be implemented, but high current densities cause reliability issues and static power dissipation
Solution Approach 1:
The patent substitutes current-driven magnetic switching with voltage-controlled magnetoelectric switching. Instead of using high current densities to switch magnetization (as in spin-transfer torque devices), the invention uses electric fields to induce magnetization changes in the antiferromagnetic layer, which then control the MTJ resistance. This voltage-controlled mechanism operates at much lower current densities, improving reliability and reducing static power dissipation.
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 solution enables efficient logic operations with reduced static power dissipation, nonlinearity, gain, and concatenability, preventing feedback and performing complete Boolean operations without the need for additional devices or complex clocking schemes.
Implementation Method 1
the layer of antiferromagnetic material produces an effective magnetic field in response to the application of an electric field
Implementation Method 2
the second free magnet is magnetically coupled to the first free magnet
Implementation Method 3
a permanent magnet in contact with a second isolation layer
Data Source
AI summary
Embodiments of the present invention relate generally to logic devices, and more particularly, to magnetoelectric magnetic tunneling junction computational devices. Aspects of the disclosed technology include a stand-alone voltage-controlled magnetoelectric device that satisfies essential requirements for general logic applications, including nonlinearity, gain, concatenability, feedback prevention, and a complete set of Boolean operations based on the majority gate and inverter. Aspects of the present disclosed technology can eliminate the need for any auxiliary FETs to preset or complicated clocking schemes and prevents the racing condition.