The double perovskites with a total elemental content of LaNi0.5Mn0.5O3 and LaNi0.25Mn0.25O3 were synthesized by solid state methods, although the LaNi0.25Mn0.2503 material underwent phase separation into NiO, LaNiO3 and LaNi0.5Mn0.503. Auger Electron Spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) indicated substantial lanthanum surface segregation for the LaNio.5Mno.503 material, which formed an altered La(OH)3 layer 50-100 monolayers in thickness. The La(OH)3 could be removed by Ai' sputtering to achieve a surface of approximately stoichiometric concentration. Heating the La(OH)3-covered LaNi0.5Mn0.503 did not regenerate the double perovskite but rather produced an overlayer of La203. While the LaNi0.25Mn0.2503 material displayed extensive phase separation, the excess nickel appeared to prevent substantial lanthanum surface segregation. (C) 2014 Elsevier B.V. All rights reserved.