Abstract
In-situ diffuse neutron scattering experiments revealed that when electric current is passed through single crystals of rutile TiO2 under conditions conducive to flash sintering, it induces the formation of parallel planes of oxygen vacancies. Specifically, a current perpendicular to the c-axis generates planes normal to the (132) reciprocal lattice vector, whereas currents aligned with the c-axis form planes normal to the (132) and to the (225) vector. The concentration of defects increases with incresing current. The structural modifications are linked to the appearance of signatures of interacting Ti3+ moments in magnetic susceptibility, signifying a structural collapse around the vacancy planes. Electrical conductivity measurements of the modified material reveal several electronic transitions between semiconducting states (via a metal-like intermediate state) with the smallest gap being 27 meV. Pristine TiO2 can be restored by heating followed by slow cooling in air. Our work suggests a novel paradigm for achieving switching of electrical conductivity related to the flash phenomenon.
| Original language | English |
|---|---|
| Article number | 101546 |
| Journal | Materials Today Physics |
| Volume | 48 |
| DOIs | |
| State | Published - Nov 2024 |
Funding
The authors would like to thank Bekki Mills and Elijah Stevens for help with the design and implementation of the new in-situ sample environment at the Spallation Neutron Source at Oak Ridge National Laboratory. Work at the University of Colorado was supported by U.S. Department of Energy, Office of Basic Energy Sciences, Office of Science, under Contract No. DE-SC0024117. Research at ORNL's SNS was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy (DOE). T.S. was supported by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education for the DOE under contract number DE-SC0014664. A.P. Y. Z. and G.C. acknowledge support by the National Science Foundation via Grant No. DMR 2204811. The authors would like to thank Bekki Mills and Elijah Stevens for help with the design and implementation of the new in-situ sample environment at the Spallation Neutron Source at Oak Ridge National Laboratory. Work at the University of Colorado was supported by U.S. Department of Energy, Office of Basic Energy Sciences, Office of Science, under Contract No. DE-SC0024117. Research at ORNL’s SNS was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy (DOE). T.S. was supported by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education for the DOE under contract number DE-SC0014664. A.P., Y. Z., and G.C. acknowledge support by the National Science Foundation via Grant No. DMR 2204811.
Keywords
- Diffuse scattering
- Flash sintering
- Memristor
- Neuromorphic computing
- Resistive switching