Epitaxial La0.7Sr0.3MnO3 thin films with two in-plane orientations on silicon substrates with yttria-stabilized zirconia and YBa2Cu3O7−δ as buffer layers

Abstract

Epitaxial La0.7Sr0.3MnO3 (LSMO) thin films were fabricated on silicon substrates by pulsed laser deposition utilizing yttria-stabilized zirconia (YSZ) and YBa2Cu3O7−δ (YBCO) films as buffer layers. Structural characterization showed that the epitaxial LSMO films were (001) oriented with two in-plane orientations and exhibited a columnar growth structure. In contrast, when LSMO was deposited directly on the YSZ∕Si substrate without the YBCO template layer, it was characterized as a mixture of randomly oriented polycrystalline grains and (001)-oriented grains, without the columnar growth structure. The role of the YBCO layer for achieving the c-axis-oriented epitaxial LSMO film by introducing the dual-in-plane orientation mechanism on the YSZ∕Si substrate has been analyzed. In addition, it was found that the LSMO film with the dual-in-plane orientations on the YBCO∕YSZ∕Si substrate exhibited a much lower resistivity compared to the LSMO film directly deposited on the YSZ∕Si substrate. This effect is attributed to the existence of the randomly oriented grains in the latter, which resulted in more significant electron scattering at the grain boundaries. The higher density of grain boundaries in the LSMO film on YSZ∕Si also led to a substantially higher magnetoresistance.