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Vol. 6 No. 4 (2014)

Spin-dependent Transport Properties of CrO2 Micro Rod

https://doi.org/10.1007/s40820-014-0010-8
Zhen Wang
Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, People’s Republic of China
Li Xi
Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, People’s Republic of China
Yikai Yang
Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, People’s Republic of China
Yue Li
Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, People’s Republic of China
Xuemeng Han
Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, People’s Republic of China
Yalu Zuo
Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, People’s Republic of China
Jianbo Wang
Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, People’s Republic of China

Corresponding Author: Li Xi

xili@lzu.edu.cn

Nano-Micro Letters, Vol. 6 No. 4 (2014), Article Number: 365-371

Abstract

The CrO2 micro rod powder was synthesized by decomposing the CrO3 flakes at a specific temperature to yield precursor and annealing such a precursor in a sealed glass tube. The magneto-transport properties have been measured by a direct current four-probe method using a Cu/CrO2 rods/colloidal silver liquid electrode sandwich device. The largest magnetoresistance (MR) around ~72 % was observed at 77 K with applied current of 0.05 μA. The non-linear I–V curve indicates a tunneling type transport properties and the tunneling barrier height is around 2.2 ± 0.04 eV at 77 K, which is obtained with fitting the non-linear I–V curves using Simmons’ equation. A mixing of Cr oxides on the surface of CrO2 rod observed by X-ray photoemission spectroscopy provides a tunneling barrier rather than a single phase of Cr2O3 insulating barrier. The MR shows strong bias voltage dependence and is ascribed to the two-step tunneling process.

Keywords

CrO2 rod Low-field magnetoresistance Tunneling barrier Bias voltage dependence
Wang, Zhen, Li Xi, Yikai Yang, Yue Li, Xuemeng Han, Yalu Zuo, and Jianbo Wang. 2014. “Spin-Dependent Transport Properties of CrO2 Micro Rod”. Nano-Micro Letters 6 (4):365-71. https://doi.org/10.1007/s40820-014-0010-8.
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