Magnetic state of a GdBaCo$_{1.86}$O$_{5.0}$ single crystal

Single crystals of double-layered cobaltites with the general formula GdBaCo$_{2-x}$O$_{5.5-\delta}$ have been studied. It has been shown that a large number of vacancies in the cobalt and oxygen sublattices of GdBaCo$_{1.86}$O$_{5.0}$ affect their magnetic state. The comparison of the magnetic properties of the GdBaCo$_{1.86}$O$_{5.0}$ and GdBaCo$_{1.86}$O$_{5.32}$ single crystals has shown that a decrease in the concentration of oxygen ions at the same number of Co ions results in the breaking of Co-O-Co exchange bonds and the implementation of a magnetically ordered state at lower temperatures compared to GdBaCo$_{1.86}$O$_{5.32}$.