When iron atoms behave like rare-earth elements - and why

Authors: Michael L. Baker (The University of Manchester; The University of Manchester at Harwell) , Myron S. Huzan (The University of Manchester; The University of Manchester at Harwell)
Co-authored by industrial partner: No

Type: Diamond Annual Review Highlight

State: Published (Approved)
Published: July 2021
Diamond Proposal Number(s): 21117 , 23982

Abstract: The clean energy revolution demands large quantities of rare-earth elements in applications ranging from wind turbines to electric car motors. However, rare-earth metals are toxic, and extraction is an energy-intensive and environmentally damaging process. Iron- doped lithium nitride has extraordinary magnetic properties, with single-ion magnetism that exceeds any other transition metal system and a magnetic coercivity field that surpasses even the largest values observed in rare-earth-based permanent magnets. However, unanswered questions concerning the fundamental geometric and electronic structure of the iron sites limit its impact. Researchers used a combination of element-sensitive X-ray techniques on Diamond Light Source’s Scanning Branch of beamline I20 to investigate the iron sites. They used K-edge X-ray Absorption Near Edge Structure (XANES) to quantify iron coordination geometry, Extended X-ray Absorption Fine Structure (EXAFS) to deduce the bond lengths around iron sites and Kβ X-ray Emission Spectroscopy (XES) to measure iron oxidation state as a function of dopant concentration. To directly access the electrons that contribute to the magnetism at iron sites, they used I10: Beamline for Advanced Dichroism Experiments (BLADE). The insights gained into the electronic structure will inform the preparation of improved bulk magnets that do not require rare-earth elements. The results of this study provide insights into how transition metals within host lattices could one day offer a viable alternative to rare-earth bulk magnets. It may also become possible to use the direction of magnetisation at the iron atoms to store binary information at the atomic scale, for future high-density information storage applications and advances in quantum computing.

Journal Keywords: Single-ion magnetism; Solid state; Magnetic anisotropy; Electronic structure; Transition metal dopant; X-ray spectroscopy

Subject Areas: Materials, Physics, Chemistry

Instruments: I10-Beamline for Advanced Dichroism , I20-Scanning-X-ray spectroscopy (XAS/XES)

Other Facilities: Stanford Synchrotron Radiation Lightsource

Added On: 26/11/2021 13:46

Discipline Tags:

Hard condensed matter - electronic properties Physics Chemistry Magnetism Materials Science Inorganic Chemistry

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) X-ray Emission Spectroscopy (XES) Extended X-ray Absorption Fine Structure (EXAFS) X-ray Absorption Near Edge Structure (XANES)