Lead-free BFN ceramics doped by chromium, lithium or manganese Dariusz Bochenek, Przemysław Niemiec and Małgorzata Adamczyk Eur. Phys. J. B, 88 10 (2015) 278 Published online: 26 October 2015 DOI: 10.1140/epjb/e2015-60461-2