Magnetic structure and spin fluctuations in the colossal magnetoresistance ferrimagnet <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">Mn</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">Si</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">Te</mml:mi><mml:mn>6</mml:mn></mml:msub></mml:math>

Abstract

Characterizing the magnetic structure is crucial to understand the extraordinary colossal magnetoresistance of ferrimagnetic Mn${}_{3}$Si${}_{2}$Te${}_{6}$. This material exhibits orders of magnitude reduction in resistivity when a magnetic polarization is avoided. Using single-crystal neutron diffraction, the authors reveal here the field evolution of the spin configuration. Prominent magnetic diffuse scattering is present and decays slowly well above the transition. The spin correlation lengths agree well with the electrical resistivity, underscoring the role of magnetic fluctuations contributing to the magnetoresistivity near the transition.

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