Quantum Memory Spin Transfer Torque Magnetic Junction

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Solution Overview

Problem

Conventional quantum computing devices face challenges in developing fast magnetic memories that can operate effectively at very low temperatures, such as sub-ten Kelvin, due to issues with resistance and programming speed in existing magnetic tunneling junctions.

Innovation Solution

The development of quantum computing device magnetic memories with magnetic storage cells featuring magnetic junctions comprising a reference layer, a nonmagnetic spacer layer, and a free layer, configured to allow the free layer to be switched between stable magnetic states with a nonzero initial spin transfer torque even in the absence of thermal fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional magnetic tunneling junctions are used in quantum computing device memories, then the memory can be integrated with quantum processors, but the resistance becomes too high and programming speed becomes too slow at low temperatures

Engineering Contradiction:

Improveprogramming speedVSAvoidoperational reliability at low temperature

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent changes the fundamental switching mechanism from thermal-assisted tunneling to spin transfer torque switching. This parameter change enables the magnetic junction to operate effectively at low temperatures by eliminating dependence on thermal fluctuations, thereby resolving the contradiction between programming speed and operational reliability at low temperatures

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the conventional magnetic tunneling junction mechanism with a spin transfer torque magnetic junction. This substitution introduces a new physical mechanism that uses spin-polarized current to directly switch magnetic moments, overcoming the limitations of conventional approaches at low temperatures and achieving both high speed and reliability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Temperature

If the magnetic memory operates at very low temperatures (sub-ten Kelvin), then the quantum processor can maintain qubit coherence, but conventional magnetic devices cannot program fast enough

Engineering Contradiction:

Improveoperating temperatureVSAvoidprogramming speed

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The patent fundamentally changes the switching mechanism from thermal-dependent to spin-dependent, enabling fast programming at very low temperatures. The spin transfer torque effect remains effective at sub-ten Kelvin temperatures, allowing the system to maintain both low operating temperature for quantum coherence and high programming speed

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent designs the magnetic junction with specific layer configurations (reference layer, nonmagnetic spacer, free layer) that are pre-engineered to enable spin transfer torque switching. This preliminary design ensures that the switching mechanism is inherently suitable for low-temperature operation, eliminating the need for thermal assistance during programming

Inventive Principle:

Principle #10Preliminary action

3Quantity of substance

If conventional magnetic memories are used, then storage capacity can be achieved, but the write currents are too high and switching speed is too slow for quantum computing applications

Engineering Contradiction:

Improvestorage capacityVSAvoidwrite current

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent replaces conventional magnetic switching with spin transfer torque switching, which uses spin-polarized current to exert torque on magnetic moments. This substitution dramatically reduces the write current required for switching while maintaining storage capacity, making the memory suitable for quantum computing applications where low power consumption is critical

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This configuration enables rapid programming and operation of magnetic memories at low temperatures, reducing write currents and enhancing switching speed, making them suitable for quantum computing applications.

Implementation Method 1

The magnetic junctions are configured such that the free layer has a nonzero initial writing spin transfer torque in an absence of thermal fluctuations

Methodology Applied

Scientific EffectSpin transfer torque:

Data Source

PatentUS9460397B2Quantum computing device spin transfer torque magnetic memory

Publication Date: 2016.10.04 SAMSUNG ELECTRONICS CO LTD

AI summary

A quantum computing device magnetic memory is described. The quantum computing device magnetic memory is coupled with a quantum processor including at least one quantum device corresponding to at least one qubit. The quantum computing device magnetic memory includes magnetic storage cells coupled with the quantum device(s) and bit lines coupled to the magnetic storage cells. Each of the magnetic storage cells includes at least one magnetic junction. The magnetic junction(s) include a reference layer, a nonmagnetic spacer layer, and a free layer. The nonmagnetic spacer layer is between the reference layer and the free layer. The magnetic junction(s) are configured to allow the free layer to be switched between stable magnetic states. The magnetic junction(s) are configured such that the free layer has a nonzero initial writing spin transfer torque in an absence of thermal fluctuations.