Enhancement of multiferroic properties of Pb(Fe_(1/2)Nb_(1/2))O_3 thin films on SrRuO_3 buffered SrTiO_3 substrates

摘要

We report multiferroic properties of Pb(Fe_(1/2)Nb_(1/2))O_3 (or PFN) epitaxial thin layers grown on (001), (110), and (111) SrTiO_3 substrates with and without a SrRuO_3 (SRO) buffer. Our findings are as follows: (ⅰ) the constraint stress on (001) substrates is more than ten times larger than those on (110) and (111); (ⅱ) this large constraint stress induces higher piezoelectric constants, magnetic permeability and magnetization for (001) PFN compared with (110) and (111) layers; (ⅲ) epitaxy distorts the structure of (001) PFN causing the films to be weakly ferromagnetic, whereas (110) films are antiferromagnetic; and (ⅳ) a significant increase of the coercivity of (001) layers occurs due to clamping by a SRO buffer layer.