Toroidal Magnetic Logic Element Reducing Power Consumption
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Solution Overview
Problem
Current magnetic logic elements with non-closed magnetic multilayers suffer from non-uniformity and inconsistency of magnetic and electrical properties, high operating current, and increased power consumption due to demagnetization fields and shape anisotropy, which affect the uniformity and consistency of magnetic and electrical properties.
Innovation Solution
A toroidal closed magnetic multilayered cell is used to eliminate demagnetization fields and reduce shape anisotropy, employing spin-polarized current and current-induced Oersted field for low power-consumption logic operations, with input signal lines penetrating the magnetic multilayers to create a circular magnetic field for controlling magnetization states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a non-closed magnetic multilayered cell structure (square, rectangle, circle, ellipse) is used, then the device complexity is reduced and manufacturing is easier, but demagnetization fields and shape anisotropy increase leading to higher reversal field and power consumption
Solution Approach 1:
The patent applies a toroidal (doughnut-shaped) closed magnetic multilayered cell structure that eliminates demagnetization fields at the edges by forming a continuous closed loop. This curved closed geometry replaces the non-closed square/rectangular structures, reducing shape anisotropy and the reversal field required for magnetization switching, thereby lowering the operating current and power consumption while maintaining manufacturability through standard semiconductor fabrication processes
2Device complexity
If input signal lines are disposed on the magnetic multilayers, then the device structure is simplified, but the effective magnetic field acting on the magnetic multilayered cell becomes small requiring large operation current
Solution Approach 1:
The patent positions the input signal lines in a different spatial arrangement relative to the magnetic multilayers, with signal lines disposed above and below the magnetic multilayered cell structure. This three-dimensional configuration allows the current paths to generate stronger effective magnetic fields through the magnetic layers via the Oersted field effect, increasing coupling efficiency and reducing the magnitude of operation current needed compared to planar on-top configurations
3Ease of manufacture
If a non-closed magnetic multilayered cell is used, then the manufacturing process is simpler, but vortex magnetic domains are produced affecting the uniformity and consistency of magnetic and electrical properties
Solution Approach 1:
The closed toroidal geometry eliminates free edges and corners where vortex magnetic domains typically nucleate in non-closed structures. The continuous closed-loop configuration enforces uniform magnetization circulation around the torus, preventing vortex formation and ensuring consistent magnetic and electrical properties across all cells in the array, while still allowing standard fabrication processes to be used
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 toroidal structure reduces demagnetization fields and shape anisotropy, leading to lower current and power consumption, while ensuring stability and consistency of magnetic and electrical properties, facilitating efficient logic operations.
Implementation Method 1
the switch of the magnetic moment of respective magnetic layers in the closed magnetic multilayered logic element is carried out by the spin-polarized current based on the spin torque & spin-transfer switching effect
Implementation Method 2
the switch of the magnetic moment of respective magnetic layers in the closed magnetic multilayered logic element is carried out by the spin-polarized current based on the spin torque & spin-transfer switching effect together with the current-induced Oersted field driving
Implementation Method 3
a closed magnetic multilayered logic element with no demagnetization fields and weak shape anisotropy by adopting a toroidal closed magnetic multilayered cell to eliminate the demagnetization field of the magnetic multilayers itself
Implementation Method 4
Since the end of 1980s when Baibich et al observed the giant magnetoresistance (GMR) effect in a magnetic multilayered system
Data Source
AI summary
A magnetic logic element with toroidal magnetic multilayers (5,6,8,9). The magnetic logic element comprises a toroidal closed section which is fabricated by etching a unit of magnetic multilayers (5,6,8,9) deposited on a substrate. Optionally, the magnetic logic element may also comprise a metal core (10) in the closed toroidal section. Said magnetic multilayers (5,6,8,9) unit is arranged on the input signal lines A, B, C and an output signal line O, and then is made into a closed toroidal. Subsequently, on the toroidal magnetic multilayered unit (5,6,8,9), the input signal lines A′, B′, C′ and an output signal line O′ are fabricated by etching. This magnetic logic element can reduce the demagnetization field and the shape anisotropy effectively, leading to the decrease of the reversal field of magnetic free layer. Furthermore, this magnetic logic element has stable working performance and long operation life of the device.