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Here, we have explored the effect of magnetic rare-earth dopants substitutionally incorporated on the Ba sites of $$BaSnO_3$$ in terms of electronic transport, magnetism, and optical properties. We show that for $$Ba_{0.92}R_{0.08}SnO_3$$ thin films (where $R=$ La,Pr,Nd,Gd), there is a linear increase of mobility with carrier concentration across all doping schemes. La-doped films have the highest mobilities, followed by Pr- and Nd-doped films. Gd-doped samples have the largest ionic size mismatch with the Ba site and correspondingly the lowest carrier concentrations and electron mobilities. However, crystallinity does not appear to be a strong predictor of transport phenomena; our results suggestmore » that point defects more than grain boundaries are key ingredients in tuning the conduction of $$BaSnO_3$$ films grown by pulsed laser deposition. Pronounced, nonhysteretic x-ray magnetic dichroism signals are observed for Pr-, Nd-, and Gd-doped samples, indicating paramagnetism. Finally, we probe the optical constants for each of the $$BaSnO_3$$ doping schemes and note that there is little change in the transmittance across all samples. Together these results shed light on conduction mechanisms in $$BaSnO_3$$ doped with rare-earth cations.« less

BaSnO₃ is an excellent candidate system for developing a new class of perovskite-based dilute magnetic semiconductors. Here in this study, we show that BaSn_0.95Fe_0.05O₃ can be grown from a background pressure of ~2×10-3 mTorr to oxygen pressures of 300 mTorr with high crystallinity and excellent structural quality. When grown in vacuum, the films may be weakly ferromagnetic with a nonzero x-ray magnetic circular dichroism signal on the Fe L₃ edge. Growth with oxygen flow appears to suppress magnetic ordering. Even for very thick films grown in 100 mTorr O₂, the films are paramagnetic. Finally, the existence of ferromagnetism in vacuum-grownmore » BaSnO₃ may be attributed to the F-center exchange mechanism, which relies on the presence of oxygen vacancies to facilitate the ferromagnetism. However, other possible extrinsic contributions to the magnetic ordering, such as clusters of Fe₃O₄ and FeO or contamination can also explain the observed behavior.« less

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·smore » (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 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.« less

We demonstrate reversible control of magnetization and anisotropy in La_0.67Sr_0.33MnO₃ films through interfacial oxygen migration. Gd metal capping layers deposited onto La_0.67Sr_0.33MnO₃ leach oxygen from the film through a solid-state redox reaction to form porous Gd₂O₃. X-ray absorption and polarized neutron reflectometry measurements show Mn valence alterations consistent with high oxygen vacancy concentrations, resulting in suppressed magnetization and increased coercive fields. Effects of the oxygen migration are observed both at the interface and also throughout the majority of a 40 nm thick film, suggesting extensive diffusion of oxygen vacancies. After Gd-capped La_0.67Sr_0.33MnO₃ is exposed to atmospheric oxygen for a prolongedmore » period of time, oxygen diffuses through the Gd₂O₃ layer and the magnetization of the La_0.67Sr_0.33MnO₃ returns to the uncapped value. In conclusion, these findings showcase perovskite heterostructures as ideal candidates for developing functional interfaces through chemically-induced oxygen migration.« less