Synthesis And Physical Properties Of The New Iridium Oxyfluoride Sr2ir(O, F)(6-Delta) Using A Topochemical Reaction Method

We report the synthesis of a new layered iridium oxyfluoride, Sr2Ir(O, F)(6-delta), using a topochemical fluorination method. The c axis is elongated compared to that in the mother compound Sr2IrO4, because the fluorine layer is inserted into the rock-salt layer while tetragonal symmetry is preserved. Resistivity measurements for the compound show nonmetallic behavior similar to that of Sr2IrO4. In magnetization measurements, suppression of antiferromagnetic order and paramagnetic behavior was observed after topochemical fluorination. Meanwhile, muon spin relaxation (mu SR) experiments suggest the development of antiferromagnetic spin correlation between Ir spins. Furthermore, fluorine content was estimated at 1.5 the chemical composition of the fluorinated product being Sr(2)IrO(x)F(1.5 )with x = 3.25, assuming Ir4+. Suppression of magnetic order in Sr2Ir(O, F)(6-delta) is attributed to antiferromagnetic instability between IrO2 layers by elongation of the c axis due to fluorine intercalation.