X-ray photoemission study of polycrystalline Mg(1-x)Al(x)B(2)
  Polycrystalline Mg(1-x)Al(x)B(2) (x = 0, 0.1, 0.4, 0.5, 0.6, 1) samples have been prepared by a conventional solid state reaction. The Mg 2p, Al 2p and B 1s core level binding energies have been studied using X-ray photoemission spectroscopy (XPS). It is found that Mg 2p, Al 2p and B 1s core level binding energies increase with the Al content in Mg(1-x)Al(x)B(2) when x = 0.5, and the maxima in the binding energies of Mg 2p and Al 2p are observed in sample Mg(0.5)Al(0.5)B(2). In contrast to the Mg 2p and Al 2p core levels, the B 1s binding energy shows a minimum when x = 0.5. 
Fa-Min Liu, C. Dong, J. Q. Li, T. M. Wang