MRAM Magnetization Control via In-Plane Magnetic Field
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Solution Overview
Problem
Magnetic random access memory (MRAM) devices with magnetic tunnel junction (MTJ) elements face challenges in achieving stable operations due to the changeability of magnetization direction, which affects the reliability and efficiency of data storage.
Innovation Solution
A nonvolatile memory device configuration that includes a magnetic memory element with a stacked body of a first ferromagnetic layer, a second ferromagnetic layer, and a nonmagnetic layer, where a magnetic field is applied to the second ferromagnetic layer, and a control unit changes the voltage between the layers to manipulate the magnetization direction, satisfying specific conditions to ensure stable operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the magnetization direction of the MTJ element is changed by applying voltage, then data storage capability is improved, but operational stability deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the voltage magnitude and duration during magnetization switching. By optimizing the voltage parameter (applying a specific voltage range for a controlled duration), the system achieves reliable magnetization switching while maintaining operational stability. The voltage is applied long enough to ensure complete switching but not so long as to cause instability, thus resolving the contradiction between data storage capability and operational stability.
2Ease of operation
If voltage is applied to change magnetization direction, then data writing is enabled, but switching time control becomes difficult
Solution Approach 1:
The patent employs periodic action by applying voltage in controlled pulses rather than continuously. The voltage is applied for a specific duration (the pulse width) and then terminated, allowing precise control over the switching time. This periodic voltage application enables the system to write data reliably while maintaining tight control over the switching time, resolving the contradiction between ease of operation and time loss control.
3Productivity
If magnetic field is applied to the second ferromagnetic layer, then magnetization switching is achieved, but reversal error rate increases
Solution Approach 1:
The patent implements feedback mechanisms to monitor and control the magnetization switching process. By detecting the actual switching behavior and adjusting the voltage parameters accordingly, the system ensures that switching occurs reliably without causing reversal errors. This feedback control allows high-speed switching while maintaining low error rates, resolving the contradiction between productivity and reliability.
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 proposed configuration enables stable and efficient manipulation of magnetization direction, enhancing the reliability and efficiency of data storage in MRAM devices by ensuring appropriate switching times and reducing reversal error rates.
Implementation Method 1
a magnetic field application unit configured to apply a magnetic field to the second ferromagnetic layer
Implementation Method 2
a data storage unit that uses a magnetic tunnel junction (MTJ) element that exhibits a tunneling magnetoresistive (TMR) effect
Data Source
AI summary
According to one embodiment, a nonvolatile memory device includes a memory unit and a control unit. The memory unit includes a magnetic memory element which includes: a first and second ferromagnetic layers; and a first nonmagnetic layer provided between the first and the second ferromagnetic layers. The memory unit includes a magnetic field application unit configured to apply a magnetic field to the second ferromagnetic layer, the magnetic field having a component in a first in-plane direction perpendicular to a stacking direction. The control unit is electrically connected to the magnetic memory element, and is configured to implement a setting operation of changing a voltage between the first and the second ferromagnetic layers from a first set voltage to a second set voltage. The magnetic field applied by the magnetic field application unit satisfies the condition ofΔH>(Hu+Hdx)(Hu+Hdx-Hext)(Hu+Hdx+Hext).(1)