SrEr2O4 has been characterised by low-temperature powder neutron diffraction, as well as single crystal specific heat and magnetisation measurements. Magnetisation measurements show that the magnetic system is highly anisotropic at temperature above ordering. A magnetic field of 280 kOe applied at T=1.6 K does not overcome the anisotropic magnetisation and fails to fully saturate the system. Long range antiferromagnetic ordering develops below TN=0.75 K, identified by magnetic Bragg reflections with propagation vector k=0 and a lambda anomaly in the specific heat. The magnetic structure consists of ferromagnetic chains running along the \textit{c} axis, two adjacent chains being stacked antiferromagnetically. The moments point along the \textit{c} direction, but only one of the two crystallographically in-equivalent Er sites has a sizeable ordered magnetic moment, 4.5 μB at 0.55 K. The magnetic properties of SrEr2O4 are discussed in terms of the interplay between the low-dimensionality, competing exchange interactions, dipolar interactions and low lying crystal field levels.
@article{arxiv.0808.2675,
title = {Low-temperature magnetic ordering in SrEr$_2$O$_4$},
author = {O. A. Petrenko and G. Balakrishnan and N. R. Wilson and S. de Brion and E. Suard and L. C. Chapon},
journal= {arXiv preprint arXiv:0808.2675},
year = {2008}
}