1304.5403 (S. Ghannadzadeh et al.)

Evolution of magnetic interactions in a pressure-induced Jahn-Teller
driven magnetic dimensionality switch    [PDF]

S. Ghannadzadeh, J. S. Möller, P. A. Goddard, T. Lancaster, F. Xiao, S. J. Blundell, A. Maisuradze, R. Khasanov, J. L. Manson, S. W. Tozer, D. Graf, J. A. Schlueter

We present the results of high-field magnetization and muon-spin relaxation measurements on the coordination polymer CuF_2(H_2O)_2(pyrazine) in pressures up to 22.5 kbar. We observe a transition from a quasi-two-dimensional to a quasi-one-dimensional antiferromagnetic phase at 9.1 kbar, driven by a rotation of the Jahn-Teller axis. Long-range antiferromagnetic ordering is seen in both regimes, as well as a phase separation in the critical pressure region. The magnetic dimensionality switching as pressure is increased is accompanied by a halving of the primary magnetic exchange energy J and a fivefold decrease in the ordering temperature T_N. J decreases gradually with pressure in the two-dimensional phase, and then increases in the one-dimensional regime. We relate both effects to the changes in the crystal structure with applied pressure.

View original: http://arxiv.org/abs/1304.5403