Competing magnetic interactions in the extended Kagome system YBaCo4O7

TL;DR

This paper investigates the magnetic properties of YBaCo4O7, a geometrically frustrated magnet with a Kagome structure, revealing diffuse scattering, long-range order below 110K, and a temperature-dependent spin reorientation.

Contribution

It provides the first detailed neutron diffraction study of YBaCo4O7, uncovering its unique magnetic ordering and spin reorientation phenomena.

Findings

Diffuse magnetic scattering observed over a broad temperature range

Long-range magnetic order established below 110K

Spin reorientation occurs above 30K

Abstract

YBaCo4O7 belongs to a new class of geometrically frustrated magnets like the pyrochlores, in which Co-spins occupy corners of tetrahedra. The structure can be viewed as an alternating stacking of Kagome and triangular layers. Exactly half of the triangular units of the Kagome plane are capped by Co ions to form columns running perpendicular to the Kagome sheets. Neutron powder diffraction reveals a broad temperature range of diffuse magnetic scattering, followed by long range magnetic ordering below 110K. A unique low-temperature magnetic structure simultaneously satisfies an S=0 arrangement in the uncapped triangular units and antiferromagnetic coupling along the columns. A spin reorientation above 30K tracks the relative strengths of the in-plane and out-of-plane interactions.