Spin Element Stabilization via Pulse Current Density Control

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Solution Overview

Problem

Spin elements used for data recording face instability in resistance values between low-resistance and high-resistance states, leading to fluctuations in data recording thresholds, which reduces data reliability over time.

Innovation Solution

Applying a pulse current with specific current density and pulse width under controlled temperature conditions to stabilize resistance values, involving a current-carrying part with a ferromagnetic material, and optimizing the spin-orbit torque wiring and magnetic recording layer configurations to ensure consistent resistance states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spin element is used for data recording, then data storage capability is achieved, but resistance values fluctuate between low-resistance and high-resistance states leading to data instability

Engineering Contradiction:

Improvedata stabilityVSAvoidresistance value stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies a preliminary stabilization process by flowing a first current through the spin element before normal operation, and then flowing a second current after manufacturing. This preliminary action stabilizes the resistance values in both low-resistance and high-resistance states, ensuring data reliability from the outset and preventing fluctuations during actual data recording operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by controlling current density and pulse width during the stabilization process. By applying specific current parameters (first current and second current with defined densities and pulse widths), the resistance states are adjusted and stabilized, transforming the element from an unstable state to a reliable operational state.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If multiple writing operations are performed on a spin element, then data recording capacity increases, but resistance values become unstable causing threshold fluctuations

Engineering Contradiction:

Improvewriting operation capacityVSAvoidresistance threshold consistency

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The stabilization currents are applied in advance before the spin element undergoes multiple writing operations. This preliminary stabilization ensures that even after numerous write cycles, the resistance thresholds remain consistent and reliable, maintaining data integrity throughout the element's operational life.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies cushioning by pre-stabilizing the resistance states against future degradation. The first and second currents create a protective effect that cushions the spin element against resistance fluctuations that would normally occur during repeated writing operations, ensuring long-term reliability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 method effectively stabilizes resistance values in spin elements, enhancing data reliability by maintaining consistent low- and high-resistance states over multiple write cycles, thereby improving product reliability and data integrity.

Implementation Method 1

spin-orbit-torque type magnetoresistance effect elements using spin-orbit torque (SOT), and domain wall type magnetic recording elements using the movement of a magnetic domain wall have attracted attention among spin elements using a change in magnetoresistance

Methodology Applied

Scientific EffectSpin-orbit torque:

Implementation Method 2

SOT is induced by the pure spin currents generated by a spin-orbit interaction or the Rashba effect at an interface of different kinds of materials

Methodology Applied

Scientific EffectRashba effect:

Implementation Method 3

Giant magnetoresistance (GMR) elements formed of a multi-layer film of a ferromagnetic layer and a non-magnetic layer, and tunnel magnetoresistance (TMR) elements using an insulating layer (tunnel barrier layer or barrier layer) as a non-magnetic layer have been known as an element using a change in resistance value (change in magnetoresistance) based on a change of a relative angle formed by the magnetization of two ferromagnetic layers

Methodology Applied

Scientific EffectGiant magnetoresistance:

Implementation Method 4

tunnel magnetoresistance (TMR) elements using an insulating layer (tunnel barrier layer or barrier layer) as a non-magnetic layer

Methodology Applied

Scientific EffectTunnel magnetoresistance:

Data Source

PatentEP3761384B1Stabilization method for spin elements and production method for spin elements

Publication Date: 2023.08.02 TDK CORP

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AI summary

In the method for stabilizing a spin element according to an aspect of the invention, the spin element includes a current-carrying part extending in a first direction, and an element part laminated on one surface of the current-carrying part and including a ferromagnetic material, in the case where the environmental temperature is a predetermined temperature, a pulse current having a current density of 1.0×107 A/cm2 or more and 1.0×109 A/cm2 or less and a pulse width within a predetermined range is applied at least a predetermined number of times in the first direction of the current-carrying part at intervals of a predetermined waiting time.