Boron-Based and High-Entropy Magnetic Materials

OVERVIEW

This invention presents a method for fabricating high magnetic anisotropy materials using metallic high entropy alloys and borides to create advanced magnetic recording media materials and permanent magnets without the use of rare-earth elements. The process involves sputtering multiple targets of metals or alloys onto substrates, followed by rapid thermal annealing to form crystalline phases of high entropy alloys which consist of several elements in high concentrations. Such high entropy alloys offer a new and exciting platform to explore novel materials properties. The formation of certain crystal structures during annealing results in a high magneto-crystalline anisotropy which enhances their magnetic properties. By incorporating boron into certain high entropy alloys, their magnetic properties are further enhanced through the stabilization of more complex atomic arrangements. This method allows for certain rare-earth-free high entropy alloys to exhibit high magnetic anisotropy, making them viable alternatives to rare-earth-based magnets.

BACKGROUND

The invention addresses critical issues in magnetic recording and permanent magnet technologies, including both their reliance on rare-earth elements and stringent requirements for optimized physical properties. Traditional permanent magnets like NdFeB and SmCo are dependent on rare-earth metals, making them vulnerable to supply chain risks and market volatility, while also suffering from mechanical and corrosion resistance limitations. By using high entropy materials, including high entropy alloys and borides, this invention provides a method to achieve novel rare-earth-free materials with high magnetic anisotropy and tunable physical properties, including improved mechanical properties and corrosion resistance. This advancement is crucial for industries which rely on high energy density magnets, including magnetic recording, permanent magnets, automotive, electronics, and renewable energy sectors.

Benefit

• Reduces reliance on expensive rare-earth elements, lowering production costs.
• Provides high magneto-crystalline anisotropy and stability, comparable to or potentially surpassing traditional rare-earth magnets.
• Exhibits excellent mechanical properties and corrosion resistance, ensuring longer-lasting performance.
• Suitable for mass production using industry-compatible methods, facilitating widespread adoption.
• Applicable to a wide range of industries, enhancing various technological applications.

Market Application

• Suitable for magnetic recording media such as heat-assisted magnetic recording and consumer electronic devices where the materials properties need to be optimized for multiple performance metrics.
• Enhances performance in nanomagnetic and spintronic devices such as magnetic random access memory, logic devices and magnetic field sensors where strong magnetic anisotropy is essential in ultrasmall nanomagnets.
• Provides robust, cost-effective solutions for industrial applications requiring strong magnetic materials.
• Enhances performance and durability of hybrid/electric vehicle motors and components.
• Boosts efficiency and reliability of wind turbines, power storage systems, and magnetically levitated train technologies with superior permanent magnets.

Publications

W. B. Beeson, D. Bista, H.R. Zhang, S. Krylyuk, A. Davydov, G. Yin, and Kai Liu, “Single-Phase L10-Ordered High Entropy Thin Films with High Magnetic Anisotropy”, Advanced Science, 11, 2308574 (2024); DOI:10.1002/advs.202308574.

D. Bista, W. B. Beeson, T. Sengupta, J. Jackson, S. N. Khanna, Kai Liu, and Gen Yin, “Fast ab initio design of high-entropy magnetic thin films”, Physical Review Materials, submitted; arXiv: 2404.18283.

W. B. Beeson, D. Bista, H. R. Zhang, S. Krylyuk, D. Bhattacharya, N. Naushin, R. Kukreja, A. V. Davydov, G. Yin, and Kai Liu, “Single Phase L10-Ordered High Entropy Thin Films with High Magnetic Anisotropy”, invited, 2024 IEEE 35th Magnetic Recording Conference (TMRC), pp. 64-65 (2024).