Phase Stability and Magnetic Properties of Compositionally Complex = 2 Ruddlesden-Popper Perovskites.

Four new compositionally complex perovskites with multiple (four or more) cations on the B site of the perovskites have been studied. The materials have the general formula LaSr(M)O (M = Ti, Mn, Fe, Co, and Ni) and have been synthesized via conventional solid-state synthesis. The compounds are the first reported examples of compositionally complex = 2 Ruddlesden-Popper perovskites. The structure and properties of the materials have been determined using powder X-ray diffraction, neutron diffraction, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and magnetometry. The materials are isostructural and adopt the archetypal 4/ space group with the following unit cell parameters: ∼ 3.84 Å, and ∼ 20.1 Å. The measured compositions from energy dispersive X-ray spectroscopy were LaSrTiMnFeCoNiO, LaSrMnFeCoNiO, LaSrMnFeCoNiO, and LaSrMnFeCoNiO. No magnetic contribution is observed in the neutron diffraction data, and magnetometry indicates a spin glass transition at low temperatures.