Dresden 2006 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 4: New materials

HL 4.8: Vortrag

Montag, 27. März 2006, 12:00–12:15, BEY 154

Ferromagnetism and magnetic anisotropy in Co-implanted TiO₂ — •N. Akdogan¹, B. Rameev^2,3, L. Dorosinsky⁴, H. Sozeri⁴, R. Khaibullin³, B. Aktas ², L. Tagirov^3,5, A. Nefedov¹, A. Westphalen¹, and H. Zabel¹ — ¹Institute of Experimental Physics IV, Ruhr-University Bochum, D-44780 Bochum, Germany — ²Gebze Institute of Technology, 41400 Gebze-Kocaeli, Turkey — ³Kazan Physical-Technical Institute of RAS, 420029 Kazan, Russia — ⁴TUBITAK-UME, PK 54, 41470 Gebze-Kocaeli, Turkey — ⁵Kazan State University, 420008 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 these materials.

Magnetic anisotropy of cobalt implanted single-crystalline rutile has been studied by means of MOKE and SQUID techniques. We observed for the first time strong angular dependence of the remanent magnetization and coercive field in the plane of the implanted surface: twofold anisotropy for the (100)- and fourfold anisotropy for the (001)-substrate samples. Possible origins of ferromagnetism and anisotropies in single-crystalline TiO₂ samples after Co-ion implantation are discussed.

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".