In situ study of the formation and decomposition processes, under high pressure, of an infinite-layer cuprate: Ca_0.5Sr_0.5CuO₂

The formation and decomposition processes of the Ca_0.5Sr_0.5CuO₂ high pressure phase with the so-called infinite-layer structure have been followed in-situ by energy dispersive X-ray diffraction using a synchrotron radiation source. The decomposition reaction of the infinite-layer phase is produced at 1200 °C to yield a mixture of phases including the n= 2 member of the Sr_n-1Cu_nO₂n-1 family and (Ca, Sr)₂CuO₃. This reaction implies a volume reduction and the most significant changes are observed in the a-b plane implying that the CuO₂ planes are partially condensed.