CoIr Microwave Oscillation Element with Cr Intermediate Layer
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Solution Overview
Problem
Conventional microwave assisted magnetic recording technologies face challenges in achieving stable high-frequency oscillation and efficient spin injection, particularly when using CoIr alloys in TMR/CPP-GMR elements, leading to low spin injection efficiency.
Innovation Solution
A microwave oscillation element is configured with a lamination structure comprising a CoIr oscillating layer, a Cr or Ru nonmagnetic intermediate layer, and a CoCr or CoRu polarizer layer, where each layer is strategically chosen to optimize spin asymmetry coefficients and crystal orientation, enhancing spin injection efficiency and oscillation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If CoIr alloy is used in TMR/CPP-GMR element, then oscillation frequency can be achieved, but spin injection efficiency becomes low
Solution Approach 1:
A nonmagnetic intermediate layer is introduced between the CoIr oscillating layer and the polarizer layer. This intermediate layer acts as a mediator that improves spin injection efficiency by facilitating spin transport while maintaining the high-frequency oscillation capability of the CoIr layer.
Solution Approach 2:
The invention uses a composite multilayer structure combining CoIr oscillating layer, nonmagnetic intermediate layer (Cr or Ru), and CoCr or CoRu polarizer layer. This composite structure leverages the advantageous properties of each material: CoIr for high-frequency oscillation, Cr/Ru for improved spin transport, and CoCr/CoRu for polarizer function with enhanced spin asymmetry.
2Ease of operation
If conventional microwave assisted magnetic recording is implemented, then data writing capability is achieved, but oscillation stability at high frequency is insufficient
Solution Approach 1:
The invention optimizes specific parameters including the thickness of each layer (CoIr: 3-20nm, nonmagnetic intermediate: 1-5nm, polarizer: 2-10nm), material composition (CoCr with 5-15at% Cr, CoRu with 4-14at% Ru), and magnetic field strength to achieve stable high-frequency oscillation for effective data writing.
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 significantly improves spin injection efficiency and oscillation efficiency, enabling high-frequency electromagnetic field generation that aligns with the magnetic resonant frequency of the recording medium, facilitating effective microwave assisted magnetic recording.
Implementation Method 1
When, in the spin wave excitation element, current is applied in a direction perpendicular to a surface of each layer of the multilayer, this applied current transfers an electron spin. Due to the transfer of the spin, a spin torque is generated
Implementation Method 2
a spin torque is generated, and due to the spin torque, a spin precession is excited on the magnetization free layer. In other words, due to spin polarized current injected from the magnetization pinned layer to the magnetization free layer by current flowing, the spin precession is excited on the magnetization free layer
Implementation Method 3
A high frequency electromagnetic field in a microwave region leaks from the oscillating layer in which the spin wave is excited, and a magnetization of a magnetic recording layer of a magnetic recording medium which is a writing object, receiving the electromagnetic field, fluctuates
Implementation Method 4
the polarizer layer and the reference layer are respectively magnetized in a perpendicular direction to an in-plane; and the oscillating layer has an easy magnetization axis in a horizontal direction to an in-plane
Data Source
AI summary
A microwave oscillation element of the present invention includes a lamination main part in which an oscillating layer that is a magnetization free layer and that generates a high frequency electromagnetic field by an excitation of a spin wave, a nonmagnetic intermediate layer, a polarizer layer, and a reference layer that is to be a base magnetic layer of a spin transfer due to application of current are layered in this order. The oscillating layer is made of CoIr, the polarizer layer is configured of CoCr or CoRu; and the nonmagnetic intermediate layer is configured of Cr or Ru. As a result, the efficiency of the spin injection is improved and the microwave oscillation element where the oscillation efficiency is excellent can be realized.