Dresden 2006 – wissenschaftliches Programm

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MA: Magnetismus

MA 4: Magnetic Materials I

MA 4.1: Vortrag

Montag, 27. März 2006, 10:15–10:30, HSZ 401

Observation of two ferromagnetic phases in Co-doped rutile TiO₂ — •A. Nefedov¹, N. Akdogan¹, A Westphalen¹, R. Khaibullin², L. Tagirov², and H. Zabel¹ — ¹Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany — ²Kazan Physical-Technical Institute of RAS, 420029 Kazan, Russia

Oxide based diluted magnetic semiconductors have recently attracted considerable attention because of reports of room temperature ferromagnetism in several systems and their projected potential for spintronic devices. However, subsequent reports have raised concerns about the initially suggested intrinsic nature of ferromagnetism in this material.

The magnetic properties of Co-doped TiO₂ synthesized by ion implantation with different implantation doses have been studied using MOKE, SQUID and XRMS methods. We observe paramagnetic behaviour for low dose doped sample, but obtain clear ferromagnetic behaviour for intermediate and high dose doped samples. The drastical change of the hysteresis loop shape at the transition from the intermediate to high Coimplantation doses, demonstrating a presence of 2 ferromagnetic phases in Co-doped rutile TiO₂, has been observed. Origin of these 2 phases will be discussed during the talk.

This work was partially supported by DFG through SFB 491 and by RFBR through grant no. 04-02-97505. N Akdogan acknowledges a fellowship through the Max-Planck Research School "SurMat".