Co distribution in ferromagnetic rutile Co-doped TiO$_2$ thin films grown by laser ablation on silicon substrates

TL;DR

This study demonstrates the successful fabrication of ferromagnetic Co-doped TiO$_2$ thin films on silicon substrates with Curie temperatures above 400 K, showing potential for spintronic applications.

Contribution

It provides a simple pulsed laser deposition method to produce ferromagnetic Co-doped TiO$_2$ films with high Curie temperatures on silicon substrates.

Findings

Films are ferromagnetic above room temperature.

Co atoms are mostly near the surface but ferromagnetism originates from the matrix.

Curie temperature exceeds 400 K.

Abstract

Pure rutile Co-doped TiO$_2$ films were fabricated successfully by the conventional pulsed laser deposition technique on silicon substrates from a ceramic target. Under the right fabrication conditions, Co concentration in the films could be almost the same as in the synthesized target, and films under various conditions all are ferromagnetic well above room temperature. Even though Rutherford backscattering spectroscopy measurements show that Co atoms seem to be mostly localized near the surface of the films and less exist in deeper levels, other experimental evidences show that the ferromagnetism does not come from Co segregations but from the Co-doped TiO$_2$ matrix. Rutile Ti$_1-x$Co$_x$O$_2$ thin films grown by a very simple technique on low-price silicon substrates showing Curie temperature (TC) above 400 K appear to be very attractive to applications.