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High-temperature weak ferromagnetism in a low-density free-electron gas
D P Young1, D Hall1, M E Torelli1
1NHMFL, Florida State University, Tallahassee, Florida 32306, USA.
Nature
|April 19, 2018
Summary
Researchers experimentally investigated the magnetic properties of a low-density electron gas. Findings suggest the ground state is ferromagnetically polarized, with a high magnetic ordering temperature in electron-doped calcium hexaboride (CaB6).
Area of Science:
- Condensed Matter Physics
- Materials Science
Background:
- The magnetic ground state of low-density 3D free-electron gases has been theoretically debated for 70 years.
- Experimental investigation of this phenomenon has been lacking.
Purpose of the Study:
- To experimentally determine the magnetic properties of the ground state in a low-density electron gas.
- To investigate electron-doped calcium hexaboride (CaB6) as a potential system for studying itinerant ferromagnetism.
Main Methods:
- Measurements of magnetic properties on electron-doped calcium hexaboride (CaB6).
- Characterization of the electron gas density and magnetic ordering temperature.
Main Results:
- Evidence for ferromagnetic polarization in the ground state of the electron gas at a density of 7×1019 electrons cm-3.
- A saturation magnetic moment of 0.07 µB per electron was observed.
- An unexpectedly high magnetic ordering temperature of 600 K was determined for this itinerant ferromagnet.
Conclusions:
- The study provides the first experimental evidence for ferromagnetic polarization in a low-density free-electron gas.
- Electron-doped CaB6 exhibits properties of an itinerant ferromagnet with a high ordering temperature near the Fermi temperature.
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