Workshop "NMR, µSR, Mössbauer spectroscopies in the study of Fe-based and other unconventional high-Tc superconductors"
Non-collinear magnetism and spin dynamics in La2O2Fe2OSe2 - a µSR, NMR and Mössbauer study
Sirko Kamusella, TU Dresden, Germany
We present a detailed local probe study of the magnetic order in the oxychalcogenide La2O2Fe2OSe2. This system can be regarded as an insulating reference system of the Fe arsenide and chalcogenide superconductors. Moreover the new class of titanium based superconductors shares the octahedral coordination of a transition metal atoms with La2O2Fe2OSe2. From the combination of the local probe techniques we identify a non-collinear magnetic structure similar to Sr2F2Fe2OS2. The analysis of the magnetic order parameter yields an ordering temperature TN = 90.1 K and a critical exponent of ß = 0.133, which is close to the 2D Ising universality class as reported in the related oxychalcogenide family.