AIP Publishing LLC
AIP Publishing LLC
  • pubs.aip.org
  • AIP
  • AIP China
  • University Science Books
  • Resources
    • Researchers
    • Librarians
    • Publishing Partners
    • Topical Portfolios
    • Commercial Partners
  • Publications

    Find the Right Journal

    Explore the AIP Publishing collection by title, topic, impact, citations, and more.
    Browse Journals

    Latest Content

    Read about the newest discoveries and developments in the physical sciences.
    See What's New

    Publications

    • Journals
    • Books
    • Physics Today
    • AIP Conference Proceedings
    • Scilight
    • Find the Right Journal
    • Latest Content
  • About
    • About Us
    • News and Announcements
    • Careers
    • Events
    • Leadership
    • Contact
  • pubs.aip.org
  • AIP
  • AIP China
  • University Science Books

Three’s Company: New Alloy Sets Magnetism Benchmark

  • February 13, 2018
  • Applied Physics Letters
  • News
Share:

Preliminary atomic moment results for new iron-cobalt-manganese thin film blow past decades-old record by potentially 50 percent. 

WASHINGTON, D.C., February 13, 2018 — ­The burgeoning field of spintronics leverages electron spins — as opposed to their charge — to enhance solid-state devices like hard drives and cell phone components by prolonging battery life. Spintronic developments, however, are increasingly running up against a barrier known as the Slater-Pauling limit, the maximum for how tightly a material can pack its magnetization. Now, a new thin film is poised to break through this decades-old benchmark. 

A team of researchers from Montana State University and Lawrence Berkeley National Laboratory announces this week in Applied Physics Letters, from AIP Publishing, that they constructed a stable thin film made from iron, cobalt and manganese that boasts an average atomic moment potentially 50 percent greater than the Slater-Pauling limit. Made with a technique known as molecular beam epitaxy (MBE), the ternary body-centered cubic (bcc) alloy features a magnetization density of 3.25 Bohr magnetons per atom, besting the previously considered maximum of 2.45. 

“What we have is a potential breakthrough in one of the most important parameters of magnetic materials,” said Yves Idzerda, an author on the paper from Montana State University. “Large magnetic moments are like the strength of steel — the bigger the better.” 

The Slater-Pauling curve describes magnetization density for alloys. For decades, iron-cobalt (FeCo) binary alloys have reigned supreme, posting a maximum average atomic moment of 2.45 Bohr magnetons per atom and defining the current limit for stable alloy magnetization density. Previously, researchers mixed FeCo alloys with high-magnetic-moment transition metals, like manganese. When these ternary alloys are made, however, they lose much of their bcc structure, a key component to their high magnetism. 

Instead, this team turned to MBE, a meticulous technique akin to draping a substrate with beads of individual metal atoms, one layer at a time, to create a 10-20 nanometer film of Fe9Co62Mn29. Roughly 60 percent of the available compositions kept the bcc structure as a thin film, compared to only 25 percent in bulk. 

To better understand the alloy’s composition and structure, the group used X-ray absorption spectroscopy and reflection high-energy-electron diffraction. The X-ray magnetic circular dichroism results showed that the new material yielded an average atomic moment of 3.25 Bohr magnetons per atom. When tested with a more standard vibrating sample magnetometry, even though this magnetization density dropped, it was still significantly above the Slater-Pauling limit — 2.72. 

Idzerda said this discrepancy will provide areas of future research, adding that the interface between manganese and the substrate within the crystal might account for the gap. 

“I have guarded optimism for this because the technique we used is a little bit nonstandard and we have to convince the community of this material’s performance,” Idzerda said. 

Idzerda and his team will now investigate the robustness of iron-cobalt-manganese alloys, and more efficient fabrication techniques. They also plan to explore how molecular beam epitaxy might lead to other highly magnetic thin films, potentially mixing together four or more transition metals. 

###

For More Information:
Julia Majors
media@aip.org
301-209-3090
@AIPPhysicsNews

Article Title

Large moments in bcc FexCoyMnz ternary alloy thin films

Authors

Ryan Snow, Harsh Bhatkar, Alpha T. N'Diaye, Elke Arenholz and Yves Idzerda

Author Affiliations

Montana State University, Lawrence Berkeley National Laboratory


Applied Physics Letters

Applied Physics Letters features concise, rapid reports on significant new findings in applied physics. The journal covers new experimental and theoretical research on applications of physics phenomena related to all branches of science, engineering, and modern technology.
Share:
  • First 3-D Imaging of Excited Quantum Dots
  • New Turbulent Transport Modeling Shows Multiscale Fluctuations in Heated Plasma

Keep Up With AIP Publishing

Sign up for the AIP newsletter to receive the latest news and information from AIP Publishing.
Sign Up

AIP PUBLISHING

1305 Walt Whitman Road,
Suite 110
Melville, NY 11747
(516) 576-2200

Resources

  • Researchers
  • Librarians
  • Publishing Partners
  • Commercial Partners

About

  • About Us
  • Careers 
  • Leadership

Support

  • Contact Us
  • Terms Of Use
  • Privacy Policy

© 2025 AIP Publishing LLC
  • 𝕏