Epitaxial LnNiO3 (Ln = La, Pr, Nd, Sm) films from 4f–3d heterometallic complexes

A new approach to synthesis of epitaxial thin film of lanthanide nickelates, LnNiO3 (Ln = La, Pr, Nd, Sm), on single crystal surfaces using solutions of heterometallic complexes as precursors has been developed. The precursors of two types were selected: (1) the complexonates LnNi(DTPA)∙nH2O (H5DTPA — diethylenetriaminepentaacetic acid) and (2) complexes Ni(mosalen)Ln(piv)3 (H2mosalen — N,N′-ethylene-bis(3-metoxy-salicylaldiimin), Hpiv — pivalic acid). The use of heterometallic complexes as precursors allowed to deposit epitaxial films of rare earth nickelates with annealing at low temperature–low oxygen conditions. The LaNiO3 film deposited from LaNi(DTPA)∙nH2O precursor solution on (001)SrTiO3 substrate was successfully used as sublayer for highly textured KNbO3 film grown by MOCVD.