Synthesis method comparison of compositionally complex rare earth‐based Ruddlesden–Popper n = 1 T′‐type cuprates

The multicomponent approach has been successfully expanded to the Ruddlesden–Popper structure with the synthesis of two different high‐entropy cuprate compositions: (La0.2Nd0.2Gd0.2Tb0.2Dy0.2)2CuO4 and (La0.2Pr0.2Nd0.2Sm0.2Eu0.2)2CuO4. The effect of synthesis method is explored using both solid‐state reaction and polymeric steric entrapment (PSE) methods. It is found that PSE leads to more randomly distributed cation species, providing an advantageous method of synthesis for the growing field of high entropy oxides. In situ high‐temperature x‐ray diffraction tracks the amorphous to crystalline phase transformation in (La0.2Nd0.2Gd0.2Tb0.2Dy0.2)2CuO4 powder, synthesized using the PSE method. Using the High‐Temperature XRD data, a method for gaining information on the kinetic behavior is also applied. Magnetometry of both compositions indicates ferrimagnetic behavior at low temperatures.