Similarly, it has not been reported that volume change due to a small amount of Ru vacancy causing subtle change of the Ru-O-Ru bond angle can induce a significant change of spin configuration in SRO [1, 26]. The orthorhombic-to-tetragonal structural transition temperature T OT as a function of the SRO film thickness did not show a correlation with the ferromagnetic transition temperature [31]. Previously, the difference of RRR and T c has been explained
by oxygen vacancy, Ru vacancy, and surface difference. However, the SRO100 film and the SRO111 film have nearly the same lattice parameters and unit cell Navitoclax volumes because the volume difference between the two films is within the error bar of HRXRD. So, the vacancies could not explain the different RRR and T c between the two films. Since the films are as thick as approximately 100 unit cells, which is enough to neglect surface dependence, surface effects on its physical properties
must be excluded. Figure 5a shows the structural change of perovskite oxide as the tolerance Salubrinal molecular weight factor decreases from 1.0. As t = (r A + r O)/√2(r B + r O) decreases due to the insufficient radius of the A site ion inside the cube consisting of eight BO6 octahedra, Selleck Forskolin the octahedra rotate and tilt to prepare more suitable (smaller) space for smaller A site ions. The tolerance factor has a direct relation with the B-O-B buckling angle and thus electron transfer interaction between d electron in the B site and O 2p states. Thus, the tolerance factor in the perovskite was the most dominant factor to determine electric and/or magnetic properties in
most manganese oxides and nickelates [10–12]. Figure 5 Schematic diagram of structural change in terms of octahedral distortion, C1GALT1 hollow inscribed sphere, and its surrounding eight octahedra. (a) Perovskite oxide as the tolerance factor decreases from approximately 1, (b) the SRO100 film, and (c) the SRO111 film with bulk SRO. The Ru nn-distance in the film depended critically on the type of substrate orientation. Figure 5b,c shows the different effects of strain on the nearest neighbor distance between the adjacent Ru ions (≡Ru nn-distance) depending on the substrate surface orientation. The lattice of the SRO100 film is simply elongated along the c-axis direction while those along the two in-plane lattices shrank. The result is that the Ru nn-distance along the c-axis becomes larger than that of the bulk SRO (3.950 Å > 3.923 Å, approximately 0.69%) and that along two in-plane axes becomes smaller (3.905 Å < 3.923 Å, approximately -0.46%) due to the coherent growth through the epitaxial strain. If we grow SRO on top of STO (111) substrate, SRO will receive compressive strain. The deformation of SRO occurs in the following way: A Ru pseudocube of SRO consisting of eight Ru ions at each corner will transform to a rhombohedron.