In the hexagonal perovskite RbCoCl_{3} 1D antiferromagnetic correlations emerge along Co^{2+} chains below 90 K. At lower temperature complex interchain interactions set in and give rise to (partial) 3D magnetic order. Below T_{N1} = 28 K the spins are aligned parallel to the caxis, but 1/3 of the chains are uncorrelated from their neighbors. Only below T_{N2} = 13 K the system achieves a fully ordered state.
RbCoCl_{3} is an excellent material to study the physics of Ising chains. The magnetic structures [1] build an important foundation for the accurate interpretation of the spin dynamics measured in each case [2].
This work was carried out in the groups of PD Dr. Karl Krämer (DCBP) and Prof. Dr. Christian Rüegg (PSI) using the facilities SINQ and SLS at PSI, ISIS (UK), and ILL (F).
References:

N. P. Hänni, D. Sheptyakov, M. Mena, E. Hirtenlechner, L. Keller, U. Stuhr, L.P. Regnault, M. Medarde, A. Cervellino, Ch. Rüegg, B. Normand, K. W. Krämer;
"Magnetic order in the quasionedimensional Ising system RbCoCl_{3}"
Phys. Rev. B, 2021, 103(9), 094424/113;
doi:10.1103/PhysRevB.103.094424 & arXiv:2102.01099.

M. Mena, N. Hänni, S. Ward, E. Hirtenlechner, R. Bewley, C. Hubig, U. Schollwöck, B. Normand, K. W. Krämer, D. F. McMorrow, Ch. Rüegg;
"Thermal control of spin excitations in the coupled Isingchain material RbCoCl_{3}"
Phys. Rev. Lett., 2020, 124(5), 257201/16;
doi:10.1103/PhysRevLett.124.257201 & arXiv:1811.07178.
