Abstract
Single crystals of are investigated with neutron scattering measurements from the viewpoint of geometrical frustration. Magnetic diffuse scattering was distributed along the first Brillouin zone boundary of the fcc structure. The results show that the frustration occurs between the antiferromagnetically coupled third-neighbor spins, rather than between the similarly coupled first-neighbor spins. In addition, another type of diffuse scattering was found around some nuclear Bragg peak positions. This indicates that the first-neighbor exchange interaction in the 90° configuration is ferromagnetic rather than antiferromagnetic. Energy spectra were investigated at several points. The unusual magnetic behavior originates from the geometrical frustration and a unique property of the first-neighbor interaction.
- Received 19 June 2002
DOI:https://doi.org/10.1103/PhysRevB.68.024412
©2003 American Physical Society