Short-range Magnetic Ordering in the Geometrically Frustrated Layered Compound YBaCo4O7 with an Extended Kagom\'e Structure

摘要

Structural and magnetic properties of the geometrically frustrated layeredcompound YBaCo4O7 have been studied by magnetization and neutron diffraction. Alayered type crystal structure, with alternating tetrahedral layers of Kagom\'eand triangular types, along the c axis (hexagonal symmetry, space group P63mc)has been found. The oxygen content of the present compound was determined byiodometric titration to be 7.00{\pm}0.01. Presence of a short-rangeantiferromagnetic ordering (below TN ~ 110 K) has been concluded from theappearance of an addition broad magnetic peak (at Q ~ 1.35 {\AA}-1) in theneutron diffraction pattern. A staggered chiral type (\sqrt{3}\mult \sqrt{3} )spin structure in the Kagom\'e layers has been found. Presence of a significantmagneto-structural coupling is concluded from the changes in lattice parametersacross the magnetic ordering temperature TN ~ 110 K.