Antiperovskite Piezomagnetic Memory Cell for High-Density 3D Arrays
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Solution Overview
Problem
Current non-volatile memory (NVM) technologies face challenges such as high cost, low endurance, energy inefficiency, and limited scalability, with existing NVM cells requiring transistors for reading and writing, multiple electrodes, and being unsuitable for three-dimensional arrays due to low packing density and stackability issues.
Innovation Solution
A non-volatile memory cell utilizing a ferromagnetic storage layer with an antiperovskite piezomagnetic layer that changes its magnetic state in response to strain, allowing data to be written and read using only two electrodes through magneto-capacitance effects, and maintaining data integrity without exchange bias, enabling three-dimensional arrays with high packing density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If existing NVM technologies use transistors for reading and writing data, then data storage functionality is achieved, but device complexity increases and packing density decreases
Solution Approach 1:
The patent removes the transistor component from the memory cell structure entirely. The memory cell consists only of a ferromagnetic storage layer and an antiperovskite piezomagnetic layer, eliminating the need for transistors while maintaining read/write functionality through direct piezomagnetic coupling between the layers.
Solution Approach 2:
The antiperovskite piezomagnetic layer serves multiple functions: it acts as both the write mechanism (through strain-induced magnetisation changes) and the read mechanism (through magneto-capacitance effects). This multi-functionality eliminates the need for separate transistor-based control circuits.
2Device complexity
If existing NVM cells use multiple electrodes for reading and writing, then data access functionality is achieved, but device complexity increases and packing density decreases
Solution Approach 1:
The patent uses only two electrodes that serve both read and write functions. The same electrodes apply strain to the piezomagnetic layer for writing and measure magneto-capacitance changes for reading, eliminating the need for separate read and write electrode structures.
Solution Approach 2:
The patent combines the read and write operations into a single electrode structure. The top and bottom electrodes simultaneously enable strain application for writing and capacitance measurement for reading, merging multiple functions into a simplified two-electrode architecture.
3Productivity
If existing NVM technologies use materials with strong magnetic coupling, then writing efficiency is improved, but resistance to external magnetic fields and thermal fluctuations decreases
Solution Approach 1:
The patent changes the magnetic coupling parameter from strong exchange coupling to weak dipolar coupling. The antiperovskite piezomagnetic layer has a Neel temperature above operating temperature, creating a blocked magnetic state that provides weak, controllable dipolar coupling to the storage layer. This weak coupling enables efficient writing through strain control while providing strong resistance to external magnetic fields and thermal fluctuations.
Solution Approach 2:
The patent utilizes the phase transition of the antiperovskite piezomagnetic layer at the Neel temperature. By operating below this transition temperature, the material maintains a blocked magnetic state that provides stable, switchable magnetisation directions resistant to external perturbations while still allowing controlled switching through strain-induced effects.
4Ease of manufacture
If existing NVM cells are designed for two-dimensional arrays, then manufacturing is simplified, but packing density and scalability are limited
Solution Approach 1:
The patent transitions from two-dimensional to three-dimensional memory array architecture. The simplified two-electrode memory cell structure enables vertical stacking of multiple memory layers, achieving high-density three-dimensional arrays while maintaining ease of manufacture through the absence of complex transistor and multiple electrode structures.
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, low-power data storage with high resilience to thermal fluctuations and external magnetic fields, allowing for compact, high-density memory arrays without the need for transistors, improving performance and endurance compared to existing NVM technologies.
Implementation Method 1
a piezomagnetic layer comprised of an antiperovskite piezomagnetic material selectively having a first type of effect on the storage layer and a second type of effect on the storage layer dependent upon the strain in the piezomagnetic layer; a strain inducing layer for inducing a strain in the piezomagnetic layer
Implementation Method 2
The piezomagnetic layer forms the top plate of a planar capacitor and measuring its capacity is used to read the magnetic state of the storage layer (the magneto-capacitance effect)
Implementation Method 3
a strain inducing layer for inducing a strain in the piezomagnetic layer thereby to switch from the first type of effect to the second type of effect
Implementation Method 4
the first type of effect is one where a net magnetisation of the piezomagnetic layer is strong enough to overcome the coercive field in the storage layer and for the magnetisation of the storage layer to align with the magnetisation of the piezomagnetic layer through dipolar coupling
Data Source
AI summary
A non-volatile memory cell comprising: a storage layer comprised of a ferromagnetic or ferroelectric material in which data is recordable as a direction of magnetic or electric polarisation; a piezomagnetic layer comprised of an antiperovskite piezomagnetic material selectively having a first type of effect on the storage layer and a second type of effect on the storage layer dependent upon the magnetic state and strain in the piezomagnetic layer; and a strain inducing layer for inducing a strain in the piezomagnetic layer thereby to switch from the first type of effect to the second type of effect.