Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954
Structural, Magnetic Properties of Wide Band Gap Oxide Semiconductors46 B. Balaraju1, M. Kuppan1, S. Harinath Babu2, S. Kaleemulla1,a, N. Madhusudhana Rao1, C. Krishnamoorthi1, Girish M. Joshi3, G. Venugopal Rao4, K. Subbaravamma5, I. Omkaram6, D. Sreekantha Reddy7 1 – Thin films Laboratory, Centre for Crystal Growth, VIT University, Vellore-632014, Tamilnadu, India 2 – Department of Physics, Annamacharya Institute of Technology and Sciences, New Boyanapalli, Rajampet-516 126 andhra Pradesh, India 3 – Polymer Nanocomposite Labrotory, Centre for Crystal Growth, VIT University, Vellore-632014, Tamilnadu, India 4 – Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, Tamilnadu, India 5 – Department of Physics, AMET University, Kanthur, Chennai-603112, Tamilnadu, India 6 – Department of Electronics and Radio Engineering, KyungHee University, Yongin-si, Gyeonggi-do 446-701, Republic of Korea 7 – Department of Physics and Sungkyukwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwan – 440746, Republic of Korea a – skaleemulla@gmail.com DOI 10.2412/mmse.95.56.253 provided by Seo4U.link
Keywords: iron oxide, oxide semiconductors, particle geometry, magnetic measurements.
ABSTRACT. Iron oxide (Fe2O3), Manganese oxide (MnO2) and Nickel oxide (NiO) nanopowder samples were prepared using mechanical grinding method and subjected to their structural and magnetic properties. Microstructures, crystallite size of the nanoparticles were studied using X-ray diffractometer (XRD). Magnetic measurements were carried out using vibrating sample magnetometer low temperature (100 K). From the magnetic studies, it was found that the magnetic moment increased with increase of applied field in iron oxide and saturation was not observed even at high magnetic fields. The magnetic studies of NiO revealed ferromagnetic behaviour whereas MnO2 undergoes paramagnetic behaviour.
Introduction. In recent years dilute magnetic oxide semiconductors are finding much interest due to their important properties such as optical transmittance, electrical conductivity and ferromagnetism. Due to these reasons much focus is being put on wide band gap metal oxide semiconductors such as indium oxide, tin oxide, zinc oxide, titanium oxide, copper oxide etc. These oxide materials are so important because they possess high carrier density, wide bang gap, ease of preparation, low cost and high Curie temperature. Among the other oxides, α-Fe2O3 also one of the most important material as it finds in many potential applications. It can form four different polymorphs such as alpha, beta, gamma and epsilon [1]. If the Fe2O3 nanoparticles were prepared of the order of single domain, they exhibit interesting properties such as superparamagnetism and large coerciviy. These nanoparticles find potential applications such as gas sensors, catalyst, photovoltaics, high density magnetic storage devices, bio separation, magnetic resonance imaging agent etc.[2-5]. Moreover efforts were put for the synthesis of nanoparticles using different physical and chemical methods. The literature survey indicates that different synthesis methods such as sputtering, decomposition, hydrothermal, solvothermal, sol-gel and electrochemical processes [6-9] were applied for the synthesis of
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