Hexagonal MgXM1-XO Laminate for Spin Polarization
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Solution Overview
Problem
In devices using spin-polarized conduction electrons, achieving high-efficiency generation of spin-polarized conduction electrons is challenging due to low spin polarizability in ferromagnetic metals, which is often limited by interactions with localized spin, especially at high electron densities.
Innovation Solution
A laminate structure is developed, comprising a foundation layer with a wurtzite structure and a MgXM1-XO film with a hexagonal structure, where M is a 3d transition metal element, and 0<X<1, allowing for efficient generation of spin-polarized conduction electrons by optimizing lattice constants and film thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ferromagnetic metals such as Fe and Co are used to achieve high electron density, then conductance is improved, but spin polarizability deteriorates due to interactions with localized spin
Solution Approach 1:
The invention changes the crystal structure parameter from cubic (rock-salt) to hexagonal, which fundamentally alters the electronic band structure and spin-orbit coupling characteristics. This structural parameter change enables high spin polarizability while maintaining moderate electron density, resolving the contradiction between conductance and spin polarizability in ferromagnetic materials
Solution Approach 2:
The invention uses composite material design by combining MgO with 3d transition metal elements (Fe, Co, Ni, Mn, Cr) to form MgM1-XO compounds with hexagonal structure. This composite approach allows tuning of both electronic and magnetic properties, achieving high spin polarizability while controlling electron density through compositional parameters
2Quantity of substance
If high electron density is achieved in ferromagnetic metals, then conductance is improved, but mobility deteriorates
Solution Approach 1:
The hexagonal crystal structure change fundamentally modifies the electron effective mass and scattering mechanisms. The anisotropic hexagonal lattice provides different electron mobility characteristics compared to cubic structures, enabling improved mobility at moderate electron densities by altering the electronic band structure and reducing electron-phonon scattering
3Length of stationary object
If a wurtzite structure foundation layer is used, then lattice constants a and b are increased, but the formation of hexagonal MgXM1-XO film requires precise thickness control
Solution Approach 1:
The invention utilizes thin film technology to grow MgXM1-XO layers with precise thickness control (60 nm or smaller). The thin film approach allows exploitation of interface effects and strain engineering while maintaining the hexagonal structure, resolving the contradiction between achieving large lattice constants and controlling film thickness for phase stability
Data Source
AI summary
The present invention relates to a laminate that includes: a foundation layer (12) that is a crystal having a wurtzite structure; and a MgXM1-XO film (14) having a hexagonal film formed on the foundation layer, where M is a 3d transition metal element, and 0<X<1. The present invention also relates to a crystal that is MgXM1-XO having a hexagonal structure, where M is a 3d transition metal element, and 0<X<1.