Unusual ferromagnetism in high purity ZnO sintered ceramics

Journal Article · Sat Jan 15 00:00:00 EST 2011 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2010.09.040· OSTI ID:22209974

Das, J.; Pradhan, S. K. ^[1]; Mishra, D. K. ^[2]; Sahu, D. R. ^[3]; Sarangi, S.; Varma, S. ^[4]; Nayak, B. B. ^[2]; Huang, Jow-Lay ^[5]

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1. Institute of Materials Science, Planetarium Building, Acharya Vihar, Bhubaneswar, Orissa 751013 (India)
2. Advanced Materials Technology Department, Institute of Minerals and Materials Technology, (CSIR) Bhubaneswar 751013 (India)
3. School of Physics and DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg (South Africa)
4. Institute of Physics, Sachivalaya Marg, Bhubaneswar 751004 (India)
5. Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)

We report our novel result regarding the observation of unusual but clean ferromagnetic (FM) signature at room temperature (RT) in high pure (99.999%) ZnO bulk ceramics processed by slow step sintering schedule (SSSS). All the sintered samples showed ferromagnetic signature at room temperature. However, sample sintered at 850 {sup o}C showed more prominent M-H loop and saturation magnetization with respect to samples sintered at 500 {sup o}C and 1300 {sup o}C. Observation of FM behavior in sintered ceramics may be attributed to the presence of defects like cation (Zn)/anion (O) vacancies and interstitials created during the processing of sample. It is anticipated that SSSS promotes enhanced physical bulk as well as surface densification and at the same time confined the outgassing of free oxygen and Zn from the bulk which are acting as suitable defect sites inside the sintered grains and grain boundary junctions. Our micro-Raman and X-ray photoelectron studies revealed the existence of these defects which are believed to be the origin of the unconventional ferromagnetism (FM) of ZnO bulk ceramic at room temperature.

• OSTI ID: 22209974
• Journal Information: Materials Research Bulletin, Vol. 46, Issue 1; Other Information: Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CERAMICS
DEFECTS
FERROMAGNETISM
GRAIN BOUNDARIES
INTERSTITIALS
MAGNETIC PROPERTIES
MAGNETIZATION
PHOTOELECTRON SPECTROSCOPY
RAMAN SPECTROSCOPY
SEMICONDUCTOR MATERIALS
ZINC OXIDES