Magnetic Memory With Amorphous Underlying Layer
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Solution Overview
Problem
Current magnetic random access memory (MRAM) technologies face challenges in miniaturization and low electric current writing due to increased coercivity in magnetic storage layers and decreased spin-polarized electron injection with smaller element sizes, making it difficult to achieve both miniaturization and low electric current requirements.
Innovation Solution
A magnetic memory structure is developed with a conductive underlying layer having a polycrystalline and amorphous tantalum structure, where the thickness of the underlying layer is optimized to enhance coercivity and facilitate the formation of a magnetoresistive element with improved crystal structure and reduced resistance, allowing for efficient magnetization reversal and low electric current writing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the element size is reduced for miniaturization, then the integration density is improved, but the coercivity of the magnetic storage layer increases making write current difficult to reduce
Solution Approach 1:
The patent changes the magnetic anisotropy parameter by introducing a synthetic antiferromagnetic coupling between the storage layer and reference layer. This modifies the effective anisotropy field and reduces the coercivity of the storage layer, enabling miniaturization without requiring high write currents. The coupling strength and anisotropy can be tuned by adjusting layer thicknesses and material compositions.
Solution Approach 2:
The patent employs a composite magnetic tunnel junction structure with synthetic antiferromagnetic coupling, combining multiple magnetic layers (storage layer, reference layer, and coupling layers) to achieve the desired magnetic properties. This composite structure allows the small-volume element to maintain stable magnetization while having reduced coercivity for low-current writing.
2Volume of moving object
If the volume of the magnetic storage layer is decreased for miniaturization, then the element size is reduced, but the spin-polarized electron injection decreases making writing difficult
Solution Approach 1:
The patent introduces a nonmagnetic spacer layer as an intermediary that mediates the spin transport between the storage layer and the polarizing layer. This spacer enables efficient spin diffusion over the reduced distance in miniaturized structures, maintaining adequate spin-polarized electron injection even when the magnetic layer volume is decreased.
Solution Approach 2:
The patent optimizes the thickness and material parameters of the storage layer and surrounding layers to maintain sufficient spin polarization. By carefully controlling the layer thicknesses and using appropriate material compositions, the spin injection efficiency is preserved despite the reduced volume of the magnetic storage layer.
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 optimized structure enables high MRAM characteristics with sufficient coercivity and miniaturization, achieving both low electric current and effective information storage, addressing the limitations of existing MRAM technologies.
Implementation Method 1
The MRAM is a device which performs a memory operation by storing '1' or '0' information in a memory cell by using a magnetoresistive effect
Implementation Method 2
a write (spin injection write) scheme using spin angular momentum movement in which the magnetization direction in the storage layer is reversed by passing a spin polarization current through the MTJ element itself
Data Source
AI summary
According to one embodiment, a magnetic memory is disclosed. The magnetic memory includes an underlying structure having conductivity provided on the substrate and including a first layer with a polycrystalline structure and a second layer with an amorphous structure, and a magnetoresistive element provide on the underlying layer. The magnetoresistive element includes a first magnetic layer provided on the underlying layer, a non-magnetic layer provided on the first magnetic layer, and a second magnetic layer provided on the non-magnetic layer.