Magnetic Structure of YBaCo4O7 with Kagome- and Triangular-Lattices

TL;DR

This study investigates the magnetic structure of YBaCo4O7 with kagome and triangular lattices using neutron diffraction, revealing structural transitions and short-range magnetic order influenced by geometrical frustration.

Contribution

It provides detailed insights into the magnetic ordering and structural transitions of YBaCo4O7, highlighting the effects of geometrical frustration on magnetic behavior.

Findings

Structural transitions at ~70 K and ~105 K.

Magnetic order appears below 105 K but remains short-range.

Distinct magnetic diffuse reflections from kagome and triangular lattices.

Abstract

Neutron diffraction studies have been carried out in the temperature(T) range between 10 K and 130 K on a single crystal of YBaCo4O7, which has the stacking of kagome and triangular lattices of CoO4 tetrahedra along the c-axis. Structural transitions have been found at two temperatures Tc1~70 K and Tc2~105 K. With decreasing T, magnetic order appears along with the transition at Tc2, but it does not grow to an ideal long-range order even at the lowest T studied (~10 K). Two groups of magnetic diffuse reflections, which originate from the Co-moments of the kagome and triangular lattices, are observed separately in the reciprocal space. With further decreasing T, the growth rates of the intensities of these two are enhanced by another transition at Tc1. These magnetic behaviors seem to be related to the release of the geometrical frustration. At 10 K, the patterns of the magnetic short-range order have been determined for both sites of the kagome and triangular lattices.