Changes in the magnetic domain structure of silicon steel caused by heating with a free-running ruby laser

Abstract

{100}-oriented epitaxial Pb(Zr 0:65 Ti 0:35 )O 3 films with various film thicknesses from 0.1 to 3 m were grown on (100) c SrRuO 3 == (100)SrTiO 3 and (100) c SrRuO 3 == (100)LaNiO 3 == (001)CaF 2 substrates. The out-of-plane/in-plane lattice parameter ratio of the films on the CaF 2 substrates was larger than that on the SrTiO 3 substrates up to 1.1 m film thickness, while (90 À ) ( was defined as the internal tilt angle) was almost 0 .Results of analysis of Raman spectra and piezoresponse images suggest that the 1.1-m-thick film grown on the (100) c SrRuO 3 == (100)LaNiO 3 == (001)CaF 2 substrate had tetragonal symmetry with a polar-axis orientation. Moreover, the saturation polarization values of the films measured from P-E hysteresis loops correspond to the two P s values estimated from the thermodynamic theory, assuming the change in the polar direction due to the symmetry change to tetragonal, and from the crystal distortion in tetragonal symmetry. This can be explained by the large compressive stress from the CaF 2 substrate having a large thermal expansion coefficient. #