Electrical and magnetic properties of RE-doped ZnO thin films (RE = Gd, Nd)

被引：70

作者：

Ungureanu, Mariana ^{[1
]}

Schmidt, Heidemarie ^{[1
]}

Xu, Qingyu ^{[1
]}

von Wenckstern, Holger ^{[1
]}

Spemann, Daniel ^{[1
]}

Hochmuth, Holger ^{[1
]}

Lorenz, Michael ^{[1
]}

Grundmann, Marius ^{[1
]}

机构：

[1] Univ Leipzig, Fac Phys & Geowissensch, Inst Expt Phys 2, D-04103 Leipzig, Germany

来源：

SUPERLATTICES AND MICROSTRUCTURES | 2007年 / 42卷 / 1-6期

关键词：

diluted magnetic semiconductors; ZnO; magnetoresistance;

D O I：

10.1016/j.spmi.2007.04.022

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

Due to the small magnetic moments observed for 3d transition metals in ZnO [M. Diaconu, H. Schmidt, H. Hochmuth, M. Lorenz, G. Benndorf, J. Lenzner, D. Spernann, A. Setzer, K.W Nielsen, P. Esquinazi, M. Grundmann, Thin Solid Films 486 (2005) 117], there is still space for optimizing ZnO-based diluted magnetic semiconductors for spintronics applications. Motivated by the observation of magnetic moments as high as 4000 mu(B)/Gd atom in GaN:Gd [S. Dhar, O. Brandt, M. Ramsteiner, V.F. Sapega, K.H. Ploog, Phys. Rev. Lett. 96 (2005) 037205], we investigated ZnO films doped with 0.01, 0.1 or I at.% rare earth (RE) metals. The films, with thicknesses between 20 nm and 1 mu m, have been grown by pulsed laser deposition on a-plane sapphire or fused silica substrates. The homogenous incorporation of the RE ions in ZnO was investigated by combined Rutherford backscattering and particle induced X-ray emission measurements. Hall measurements revealed an unexpected dependence of the electron concentration on film thickness, proving a non-uniform distribution of electrically active defects. Magnetotransport measurements at different temperatures were performed to study the magnetoresistance and the presence of the anomalous Hall effect. Large negative magnetoresistance was obtained at 5 K, while no anomalous Hall effect was observed. These results indicate that there are no exchange interactions between the RE ions. (c) 2007 Elsevier Ltd. All rights reserved.

引用

页码：231 / 235

页数：5

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