Frustration of magnetic and ferroelectric long-range order in Bi(2)Mn(4/3)Ni(2/3)O(6). by Claridge, J, Hughes, H, Bridges, C, Allix, M, Suchomel, MR, Niu, H, Kuang, X, Rosseinsky, M, Bellido, N, Grebille, D, Perez, O, Simon, C, Pelloquin, D, Blundell, S, Lancaster, T, Baker, P, Pratt, F, Halasyamani, P