Single Crystal Growth of Pure Co³⁺ Oxidation State Material LaSrCoO₄

Successful growth of large high-quality LaSrCoO₄ single crystals was recently performed and reported by the crystal growth group from Max-Planck-Institute for Chemical Physics of Solids, lead by Alexander Christoph Komarek. In the emerging open access crystallography journal “Crystals” the autors write that obtaining large, impurity-free single crystals was only possible using the high O₂-pressure floating zone technique with pure oxygen at 150 bar in a ScIDre HKZ furnace. Growth speed of 2 mm/h reqiured stable conditions. Black shiny single crystals of ∼60 mm length were obtained. No impurity phase could be detected in XRD and magnetic susceptibility measurements, and there are almost no Co²⁺ impurities visible in the synchrotron X-ray absorbtion spectroscopy spectra.

So far, this is the first succesful attempt to grow sizeable single crystals with apparently big population of the Co³⁺ high-spin state, which are suitable for detailed inelastic neutron scattering experiments of pure Co³⁺ oxidation states. The recent measurements of the Max-Planck group of Alexander Komarek indicate a spin-glass transition in LaSrCoO₄, which is related to Co³⁺ ions in the high-spin state.