Gd-doped BaSnO_3: A transparent conducting oxide with localized magnetic moments

摘要

We have synthesized transparent, conducting, paramagnetic stannate thin films via rare-earth doping of BaSnO_3. Gd~(3+) (4f~7) substitution on the Ba~(2+) site results in optical transparency in the visible regime, low resistivities, and high electron mobilities, along with a significant magnetic moment. Pulsed laser deposition was used to stabilize epitaxial Ba_(0.96)Gd_(0.04)SnO_3 thin films on (001) SrTiO_3 substrates, and compared with Ba_(0.96)La_(0.04)SnO_3 and undoped BaSnO_3 thin films. Gd as well as La doping schemes result in electron mobilities at room temperature that exceed those of conventional complex oxides, with values as high as 60cm~2/V·s (n = 2.5 × 10~(20)cm~(-3)) and 30cm~2/V·s (n = 1 × 10~(20)cm~(-3)) for La and Gd doping, respectively. The resistivity shows little temperature dependence across a broad temperature range, indicating that in both types of films the transport is not dominated by phonon scattering. Gd-doped BaSnO_3 films have a strong magnetic moment of ～7 μB/Gd ion. Such an optically transparent conductor with localized magnetic moments may unlock opportunities for multifunctional devices in the design of next-generation displays and photovoltaics.