Gd-doped BaSnO₃: A transparent conducting oxide with localized magnetic moments

We have synthesized transparent, conducting, paramagnetic stannate thin films via rare-earth doping of BaSnO₃. Gd³⁺ (4f⁷) substitution on the Ba²⁺ 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_0.96Gd_0.04SnO₃ thin films on (001) SrTiO₃ substrates, and compared with Ba_0.96La_0.04SnO₃ and undoped BaSnO₃ 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 60 cm²/V·s (n = 2.5 × 10²⁰cm⁻³) and 30 cm²/V·s (n = 1 × 10²⁰cm⁻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 BaSnO₃ films have a strong magnetic moment of ∼7 μ_B/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