Nonmagnetic Doping Effect on the Magneto-Transport Properties of Mn Doped ZnO Dilute Magnetic Semiconductors
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Nonmagnetic Doping Effect on the Magneto-Transport Properties of Mn Doped ZnO Dilute Magnetic Semiconductors Govind Mundada1, Srikanth Manchiraju1, T. Kehl1, Sandhya Pulugam1, R. J. Patel2, P. Kahol1, and K. Ghosh1 1. Physics, Astronomy and Materials Science, Missouri State University, Springfield, MO 2. Center for Applied Science and Engineering, Missouri State University, Springfield, MO ABSTRACT In this paper we report nonmagnetic elements (Al and Cu) doping effect on the structural and magneto-transport properties of ZnMnO dilute magnetic semiconductors. Mn doped Zn0.85Mn0.15O (ZnMnO), Al doped Zn0.80Al0.05Mn0.15O (ZnMnAlO), and Cu doped Zn0.85Cu0.05Mn0.15O (ZnMnCuO) thin films were grown on single sapphire crystal using pulsed laser deposition (PLD) technique. X-Ray Diffraction (XRD) and Raman Spectroscopy indicate an orientation growth along the c-axis. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) measurements reveal surface microstructure of all the films. Magnetotransport properties quantify the carrier concentrations and mobilities at room temperature in all the films. INTRODUCTION Dilute Magnetic Semiconductors (DMS) are a rare group of promising materials that utilize both electronic charge, a characteristic of semiconductor materials, and electronic spin, a characteristic of magnetic materials1. This combination of charge and spin degrees of freedom in a single substance leads to a unique interplay of magnetic, optical, and electronic functionalities. They are the key materials in spintronic (spin+electronic) devices, which utilize both charge and spin degrees of freedom. Recently, DMS have received much attention due to their potential use in novel spintronic devices, electro-optic switches, and quantum-based logic and memory for high-speed computation. The success of spintronics requires a high degree of spin polarization and DMS offers 100% spin polarization2. Spin polarized devices are smaller and consume less electricity. It has been found that doping metal oxides such as ZnO, SnO2, and TiO2 with magnetic ions such as Fe, Co, and Mn produces DMS which exhibit Ferro Magnetism (FM) above room temperature. Zinc Oxide (ZnO), a short wavelength transparent opto-electronic material, is an interesting prospect for spintronics due to its unique combination of magnetic, electrical, and optical properties. The magnetic nature of Mn doped ZnO is controversial; some groups claim the presence of high Curie temperature FM in these films, while other groups claim the absence of FM3. Thus in recent years, much attention has been focused on Mn doped ZnO in order to understand the origin of ferromagnetism. ZnxMn1-xO is predominantly useful for magneto resistive random access memory (MRAM) device applications due to its wide band-gap and transparency to visible light4. Additionally, ZnO doped with manganese or non magnetic metals (Al, Cu) is a DMS which shows strong exchange interaction between s-p band carriers and localized d electrons. In this work, we report magneto-transpor
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