Evolution of ferromagnetic circular dichroism coincident with magnetization and anomalous Hall effect in Co-doped rutile TiO2

TL;DR

This study demonstrates that magnetic circular dichroism, magnetization, and anomalous Hall effect measurements in Co-doped rutile TiO2 all indicate a consistent, intrinsic ferromagnetic phase at higher carrier concentrations and Co content.

Contribution

It provides a comprehensive phase diagram linking ferromagnetism with carrier and Co levels, confirmed by multiple independent measurement techniques.

Findings

MCD, magnetization, and AHE phase diagrams match precisely.

Ferromagnetism is intrinsic and single-phase in Co-doped TiO2.

Higher carrier concentration and Co content induce ferromagnetism.

Abstract

Magnetic circular dichroism (MCD) of rutile Ti1-xCoxO2-d is systematically examined with various x and d to reveal a phase diagram for the appearance of ferromagnetism at higher carrier concentration and Co content. The phase diagram exactly matches with that determined from anomalous Hall effect (AHE). The magnetic field dependence of MCD also shows good coincidence with those of the magnetization and AHE. The coincidence of these independent measurements strongly suggests single and intrinsic ferromagnetic origin.