Bipolar Conduction and Giant Positive Magnetoresistance in Doped Metallic Titanium Oxide Heterostructures

Abstract

Empowering conventional materials with unexpected magnetoelectric properties is appealing to the multi‐functionalization of existing devices and the exploration of future electronics. Recently, owing to its unique effect in modulating a matter's properties, ultra‐small dopants, for example, H, D, and Li, attract enormous attention in creating emergent functionalities, such as superconductivity, and metal–insulator transition. Here, an observation of bipolar conduction accompanied by a giant positive magnetoresistance in D‐doped metallic Ti oxide (TiOxDy) films is reported. To overcome the challenges in intercalating the D into a crystalline oxide, a series of TiOxDy is formed by sequentially doping Ti with D and surface/interface oxidation. Intriguingly, while the electron mobility of the TiOxDy increases by an order of magnitude larger after doping, the emergent holes also exhibit high mobility. Moreover, the bipolar conduction induces a giant magnetoresistance up to 900% at 6 T, which is ≈6 times higher than its conventional phase. This study paves a way to empower conventional materials in existing electronics and induce novel electronic phases.

Carbon Nanostructures Decorated with Titania: Morphological Control and Applications

“…Another emerging area of application lies in electronics and memory devices [114,237,238]. A recent report noted that the doping of titania with hydrogen, deuterium, and lithium led to bipolar conduction and a giant positive magnetoresistance, thus significantly expanding the properties of the materials [239]. Doping with cerium enhanced the magnetic properties of semiconductors from UV-light irradiation, thanks to the ferromagnetic orientation of spin densities near oxygen vacancies in Ce-doped titania, as opposed to the anti-ferromagnetic orientations of those found in undoped titania [240].…”