Hall effect in cobalt-doped TiO$_{2-\delta}$

TL;DR

This study investigates the Hall effect in cobalt-doped TiO₂₋δ thin films, revealing different behaviors at varying carrier concentrations and suggesting a structural phase change associated with anomalous Hall signals.

Contribution

It provides new insights into the Hall effect behavior and structural changes in cobalt-doped TiO₂₋δ films across different carrier concentrations.

Findings

Low carrier concentration films show linear Hall behavior.

High carrier concentration films exhibit anomalous Hall behavior.

Structural change from rutile TiO₂ to Magneli phases correlates with anomalies.

Abstract

We report Hall effect measurements on thin films of cobalt-doped TiO$_{2-\delta}$. Films with low carrier concentrations (10$^{18}$ - 10$^{19}$) yield a linear behavior in the Hall data while those having higher carrier concentrations (10$^{21}$ - 10$^{22}$) display anomalous behavior near zero field. In the entire range of carrier concentration, n-type conduction is observed. The appearance of the anomalous behavior is accompanied by a possible structural change from rutile TiO$_{2}$ to Ti$_[n}$O$_{2n-1}$ Magneli phase(s).