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Room Temperature Ferromagnetism and Band Gap Investigations in Mg Doped ZnO RF/DC Sputtered Films

Published online by Cambridge University Press:  27 February 2013

Sreekanth K. Mahadeva
Affiliation:
Department of Materials Science, Royal Institute of Technology, Stockholm, SE100 44Sweden Department of Physics, Amrita Vishwa Vidyapeetham University, Amritapuri Campus, Kollam 690 525, Kerala, India
Zhi-Yong Quan
Affiliation:
Department of Materials Science, Royal Institute of Technology, Stockholm, SE100 44Sweden Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Shanxi Normal University, Linfen 041004, China
J. C. Fan
Affiliation:
Department of Materials Science, Royal Institute of Technology, Stockholm, SE100 44Sweden
Hasan B Albargi
Affiliation:
Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK
Gillian A Gehring
Affiliation:
Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK
Anastasia Riazanova
Affiliation:
Department of Materials Science, Royal Institute of Technology, Stockholm, SE100 44Sweden
L. Belova
Affiliation:
Department of Materials Science, Royal Institute of Technology, Stockholm, SE100 44Sweden
K. V. Rao
Affiliation:
Department of Materials Science, Royal Institute of Technology, Stockholm, SE100 44Sweden
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Abstract

Mg@ZnO thin films were prepared by DC/RF magnetron co-sputtering in (N2+O2) ambient conditions using metallic Mg and Zn targets. We present a comprehensive study of the effects of film thickness, variation of O2 content in the working gas and annealing temperature on the structural, optical and magnetic properties. The band gap energy of the films is found to increase from 4.1 to 4.24 eV with the increase of O2 partial pressures from 5 to 20 % in the working gas. The films are found to be ferromagnetic at room temperature and the saturation magnetization increases initially with the film’s thickness reaching a maximum value of 14.6 emu/cm3 and then decreases to finally become diamagnetic beyond 95 nm thickness. Intrinsic strain seems to play an important role in the observed structural and magnetic properties of the Mg@ZnO films. On annealing, the as-obtained ‘mostly amorphous’ films in the temperature range 600 to 800°C become more crystalline and consequently the saturation magnetization values reduce.

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Articles
Copyright
Copyright © Materials Research Society 2013 

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References

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