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Neutrons – Ferromagnetic topological material

Researchers performed single-crystal neutron diffraction using the HB-3A four circle diffractometer to confirm the first intrinsic ferromagnetic topological insulator. Credit: Genevieve Martin/ORNL, U.S. Dept. of Energy

A UCLA-led team that discovered the first intrinsic ferromagnetic topological insulator – a quantum material that could revolutionize next-generation electronics – used neutrons at Oak Ridge National Laboratory to help verify their finding.

Topological insulators act as insulators on the inside while allowing electrons to flow across their surfaces. Their less-studied ferromagnetic counterparts are thought to hold useful properties for quantum technology. The researchers discovered the first intrinsic ferromagnetic topological insulator – consisting of manganese, bismuth and tellurium atoms – by stacking ferromagnetic molecular layers.

To confirm the material’s intrinsic nature, the team used the High Flux Isotope Reactor at ORNL.

“Neutron diffraction's high contrast can distinguish magnetic manganese atoms from others,” said ORNL’s Huibo Cao, co-author on the study published in Science Advances. “It is well-suited for the new two-dimensional material and its magnetism.” 

“Using neutron diffraction, we concluded the atomic arrangement in each layer and confirmed the ferromagnetic order to support this discovery,” added ORNL co-author Lei Ding.