Rare Earth Oxides in Magnetic Technologies: The Hidden Backbone of the Energy Transition

Lithium, nickel, and cobalt often dominate conversations about critical materials, but some of the most important materials in the clean energy transition are far less visible. Rare earth oxides sit at the core of the permanent magnets used in electric vehicles, wind turbines, industrial automation, and robotics. Without these oxides, modern electrification would slow significantly.

This post explores the physical properties that make these oxides indispensable, the risks and constraints of global supply, and the research underway to diversify magnet materials.

Why Permanent Magnets Depend on Rare Earth Oxides

Permanent magnets derive much of their strength from rare earth elements such as neodymium, praseodymium, dysprosium, terbium, and samarium. These materials exhibit unique electron configurations that allow them to maintain strong magnetization under mechanical stress and elevated temperatures.

The two leading magnet families are:

Neodymium Iron Boron Magnets

Neodymium Iron Boron magnets deliver the highest magnetic energy density available and enable high efficiency motors in electric vehicles, industrial robotics, and wind turbine generators. A detailed technical overview of NdFeB structure and performance is available in a peer reviewed study¹.

Samarium Cobalt Magnets

Samarium Cobalt magnets offer exceptional thermal stability and corrosion resistance, which makes them essential in aerospace, defense, and high temperature industrial applications².

Rare earth oxides such as neodymium oxide, praseodymium oxide, dysprosium oxide, terbium oxide, and samarium oxide serve as high purity feedstocks during magnet alloying. Their consistency and particle morphology directly influence final magnetic performance.

The Material Science Behind High Performance

1. Grain boundary diffusion and coercivity

Oxides such as dysprosium oxide and terbium oxide are incorporated to increase coercivity and ensure stability at elevated temperatures. Their diffusion behavior at grain boundaries is well documented³.

2. Powder morphology and purity

Particle size distribution, surface area, and contamination levels heavily influence microstructure during sintering.

3. Controlled reduction from oxide to metal

Rare earth oxides must be reduced to their metallic state before alloying, and variations in reduction efficiency alter the final magnet structure and performance⁴.

Supply Chain Vulnerability and Global Risk

The rare earth oxide supply chain remains one of the most concentrated and strategically sensitive in the world. The United States Geological Survey notes that China controls a significant percentage of global rare earth separation and refining capacity⁵.

Key vulnerabilities include:

• Limited geographic diversification
• Environmental restrictions on solvent extraction processes
• Rapid demand growth from electric vehicles, wind turbines, and automation
• Scarcity of heavy rare earth elements such as dysprosium and terbium

A detailed examination of this supply chain is available through the United States Department of Energy⁶.

Recycling and Reuse: A Growing but Challenging Pathway

Recycling is gaining attention as a partial solution to rare earth supply constraints, but the technologies remain complex and are still scaling. One major pathway is hydrometallurgical recycling, in which spent magnets are dissolved and their rare earth elements are recovered through solvent extraction⁷. This process can produce high-purity outputs but requires sophisticated chemical handling and generates secondary waste streams that must be managed carefully.

Another developing approach is direct reuse and reprocessing, where magnets are demagnetized, milled, and reformed into new shapes without first being converted back into oxides⁸. This route preserves more of the original magnet’s structure and can be more energy efficient, but it is sensitive to contamination and variations in feedstock quality.

A recent study provides a comprehensive evaluation of these recycling pathways and their commercial potential⁹. Although both approaches show meaningful promise, recycling currently supplies only a small fraction of global rare earth demand, and significant advances in technology, collection infrastructure, and economic incentives will be needed for it to play a larger role in the supply chain.

Material Alternatives and Research Frontiers

Researchers are actively exploring material alternatives that could reduce long-term reliance on traditional rare earth elements. One area of growing interest is cerium-based magnet systems, which leverage cerium’s abundance and low cost. Although cerium does not match the magnetic strength of neodymium or samarium, ongoing research is testing its suitability in hybrid or partially substituted magnet formulations¹⁰.

Another promising direction involves advanced ferrites. These materials are already inexpensive, stable, and widely used, but improvements in microstructure control and grain engineering may enable ferrites to serve in applications that previously required rare earth magnets. While they cannot yet achieve the energy density of NdFeB, their scalability and cost advantages continue to attract research investment.

Finally, manganese-based magnetic materials are emerging as a frontier of exploratory work. Some manganese alloy systems show encouraging magnetic behavior, but none have yet matched the performance of established rare earth magnet families. As research progresses, combinations of manganese, iron, and other transition metals may offer pathways to rare-earth-lean or rare-earth-free alternatives.

The Path Forward for Rare Earth Materials

Rare earth oxides remain foundational to the clean energy transition. Their exceptional magnetic properties enable efficient motors, generators, sensors, and automation systems across modern sectors. At the same time, the supply chain for these materials is constrained by geographic concentration, environmental complexity, and rising global demand.

Long term stability will depend on diversified sourcing, continued improvements in recycling technologies, and ongoing research into alternative magnetic materials. As the transition to electrification accelerates, reliable access to high quality rare earth oxides will become even more critical.

Reade supports this shift by supplying specialty oxides, metals, and advanced materials sourced with rigorous quality standards. Our work with research teams, manufacturers, and emerging technology partners helps ensure that the materials behind next generation magnets are available, consistent, and ready for scaling. By strengthening the link between material science and practical supply, Reade contributes to a more resilient foundation for the energy systems of the future.

References

¹ H. Sepehri-Amin et al., “Significant Progress for Hot-Deformed Nd-Fe-B Magnets: A Review,” Materials 16(13), 4789 (2023).

² “Samarium Cobalt Magnets: Features and Applications,” Stanford Magnets Knowledge Base.

³ H. Sepehri-Amin, T. Ohkubo, K. Hono, “The mechanism of coercivity enhancement by the grain boundary diffusion process of Nd-Fe-B sintered magnets,” Acta Materialia 61(6), 1982–1990 (2013).

⁴ T. Larochelle, “Rare Earth Element Reduction to Metals,” in Rare Earth Metals and Minerals Industries (Springer, 2024).

⁵ U.S. Geological Survey, “Rare Earths,” Mineral Commodity Summaries 2024.

⁶ U.S. Department of Energy, Rare Earth Permanent Magnets: Supply Chain Deep Dive Assessment (2022).

⁷ H. Liu et al., “Hydrometallurgical Recovery of Rare Earth Elements from NdFeB Permanent Magnet Scrap: A Review,” Metals 10(6), 841 (2020).

⁸ V. Angelakeris et al., “Direct Reuse of Spent Nd–Fe–B Permanent Magnets,” Materials 18(13), 2946 (2025).

⁹ C. Deng et al., “The current status of recycling technology for waste NdFeB resources,” Journal of Material Cycles and Waste Management 27, 796–811 (2025).

¹⁰ K. P. Skokov, O. Gutfleisch, “Heavy rare-earth free, free rare-earth and rare-earth reduced magnets for energy applications,” Science 350(6263), 759–761 (2015).