Perovskite Nitride Magnetic Memory Cells for Lower Switching Power
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Solution Overview
Problem
Existing MRAM technologies face challenges such as high power consumption, limited thermal stability, and scalability due to high switching current densities, thermal instability, sensitivity to external magnetic fields, and low ON/OFF ratios.
Innovation Solution
A magnetic device with a tri-layer structure comprising perovskite-based nitride materials for the spacer layer and metallic antiperovskite nitride materials for the electrode layers, which maintains high spin polarization and lattice stability, allowing for high magnetoresistance and improved thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spin-transfer torque switching (STT-MRAM) is used, then non-volatile memory functionality is achieved, but power consumption increases due to high switching current densities
Solution Approach 1:
The patent changes the material parameters of the magnetic electrodes by using ferrimagnetic materials with compensated magnetisation, which fundamentally alters the switching mechanism and reduces the required switching current density compared to conventional ferromagnetic materials
Solution Approach 2:
The invention employs composite material structures including ferrimagnetic electrode layers combined with specific spacer layers (Ru, Ir, Rh) and capping layers, creating a multi-layer composite system that optimizes both the switching efficiency and reduces power consumption
2Reliability
If conventional magnetic electrode materials are used, then magnetic switching is achieved, but thermal stability is limited at high temperatures
Solution Approach 1:
The patent utilizes the temperature-independent nature of ferrimagnetic materials with compensated magnetisation, where the opposing magnetic moments of different sublattices cancel each other out, providing inherent thermal stability and maintaining magnetic switching capability at elevated temperatures
Solution Approach 2:
The invention employs readily available transition metal elements (Fe, Co, Ni, Mn) in specific stoichiometric ratios to create stable ferrimagnetic compounds that provide long-term thermal stability without requiring exotic or expensive materials
3Productivity
If existing magnetic device structures are used, then memory operation is achieved, but scalability is limited due to low ON/OFF ratios
Solution Approach 1:
The patent introduces local quality variations through specific interface engineering between magnetic electrode layers and spacer layers, creating localized spin scattering centers that enhance the magnetoresistance effect and improve ON/OFF ratio at the nanoscale
Solution Approach 2:
The invention uses intermediary spacer layers (Ru, Ir, Rh) with specific atomic and electronic structures that mediate the interaction between magnetic electrodes, enhancing spin-dependent scattering and improving the ON/OFF ratio without requiring extreme manufacturing precision
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 device achieves high magnetoresistance, thermal stability, and scalability, making it suitable for non-volatile memory applications with low sensitivity to external magnetic fields and reduced power consumption.
Implementation Method 1
the relative (net) magnetisation orientation of the first and second magnetic electrode layers (i.e. relative to each other) is switchable between a parallel and antiparallel (net magnetisation) state to control a spin-polarised current through the device
Implementation Method 2
The all-perovskite structure provides high mechanical stability and good lattice match between the individual layers which promotes high quality interfaces and endurance. Meanwhile, the all-nitride nature of the tri-layer provides a less abrupt change in the lattice constituents at the interfaces between electrode layers and the spacer layer. The resulting low lattice disorder at the electrode-spacer interfaces ensures low scattering and high spin coherence which contributes to maintaining a high spin polarization of the current across the interfaces. This, combined with efficient k-filtering in the spacer layer, can provide high GMR or TMR.
Implementation Method 3
The spacer layer can be a conductive spacer, in which case the device can operate as a spin valve, or a tunnel barrier in which case the device can operate as a magnetic tunnel junction (MTJ).
Data Source
AI summary
The invention provides a magnetic device and memory cell, and relates to the field of magnetic devices for memory including perovskite-based electrode materials, comprising: a spacer layer; a first magnetic electrode layer located on one side of the spacer layer; and a second magnetic electrode layer located on the other side of the spacer layer; the spacer layer comprises a perovskite nitride material or perovskite oxynitride material; the first magnetic electrode layer and the second magnetic electrode layer respectively comprises a metallic antiperovskite nitride material; the relative net magnetization orientation of the first magnetic electrode layer and the second magnetic electrode layer is switchable between a parallel net magnetization state or an antiparallel net magnetization state to control a spin-polarised current therethrough; the memory cell is applied to a memory or storage device, comprising the magnetic device, wherein the data is recordable as a parallel or antiparallel net magnetization state of the first magnetic electrode layer and the second magnetic electrode layer of the magnetic device, to solve the problems of high power consumption, poor thermal stability and limited scalability of existing magnetic devices.