Magnetic excitations in a two a dimensional J1/J1’ rectangular lattice coupled by oxalate and fluoride bridges

We wish to study the first in a new series of recently synthesised compounds exhibiting low dimensionsal magnetism in which 3d transition metal ions are exchange coupled via oxalate and fluoride bridges. In this particular structure the Fe or Co ions lie at the corners of a rectangular lattice within a layer that is exchange decoupled from neighbouring layer. While the essential exchange coupiing is two dimensional the system does exhibit long range three dimensonal antiferromagnetic order, though the structure adopted is different for Fe and Co. We propose to study the spin wave excitations below the ordering transition and also signatures of the two dimensional correlations close to and above the transition. We would also like to look for low lying single ion exictations that might lead to local anisotropy influencing the long range order stabiised via dipolar interlay coupling.