Electrical domain fixing in Cu- and Mn-doped (K0.5Na0.5)0.2(Sr0.75Ba 0.25)0.9Nb2O6 (KNSBN) crystals is presented. The relation between the applied field and the revealed grating in single and multidomain crystals is investigated. In multidomain Mn-doped KNSBN, a revealing efficiency of over 233% is obtained. The mechanism of domain fixing in single and multidomain crystal is discussed. �� 2000 American Institute of Physics.