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Ti doped hematite α-Fe2-xTixO3 (x = 0.0, 0.0206 and 0.0344) samples are synthesized using solid-state ceramic route technique. Single phase and corundum (Al2O3) type structure is revealed from the X-ray diffraction (XRD) pattern. On substitution of Ti at Fe site, all Raman active modes are shifted to higher wave numbers. An additional feature of Eu (LO) mode at about 660 cm–1 is observed. The Eu mode frequency is decreased and pronounced systematically as a function of Ti doping, and it reaches a value of 658 cm-1 for x = 0.0344. The coercivity Hc (remanence Mr) for x = 0.0, 0.0206 and 0.0344 are determined to be 995 Oe (0.44 emu/mg), 1404 Oe (0.00019 emu/mg) and 2023 Oe (0.00016 emu/mg), respectively. The larger coercivity for Ti doped samples can be attributed to their enhanced shape and magneto-crystalline anisotropy. The observed isomer shift (δ) from room temperature Mössbauer data clearly shows the presence of ferric (Fe3+) and Ti4+ ions illustrating strong ferromagnetic ordering up to x = 0.0206 in α-Fe2-xTixO3 hematite and weak ferromagnetic ordering of α-Fe2-xTixO3 for x = 0.0344.


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Structural, vibrational and magnetic properties of Ti substituted bulk hematite: α-Fe2-xTixO3

Show Author's information Dinesh VARSHNEYa( )Arvind YOGIa,b
Materials Science Laboratory, School of Physics, Vigyan Bhawan, Devi Ahilya University, Khandwa Road Campus, Indore 452001, India
School of Physics, Indian Institute of Science Education and Research, Thiruvananthapuram 695016, India

Abstract

Ti doped hematite α-Fe2-xTixO3 (x = 0.0, 0.0206 and 0.0344) samples are synthesized using solid-state ceramic route technique. Single phase and corundum (Al2O3) type structure is revealed from the X-ray diffraction (XRD) pattern. On substitution of Ti at Fe site, all Raman active modes are shifted to higher wave numbers. An additional feature of Eu (LO) mode at about 660 cm–1 is observed. The Eu mode frequency is decreased and pronounced systematically as a function of Ti doping, and it reaches a value of 658 cm-1 for x = 0.0344. The coercivity Hc (remanence Mr) for x = 0.0, 0.0206 and 0.0344 are determined to be 995 Oe (0.44 emu/mg), 1404 Oe (0.00019 emu/mg) and 2023 Oe (0.00016 emu/mg), respectively. The larger coercivity for Ti doped samples can be attributed to their enhanced shape and magneto-crystalline anisotropy. The observed isomer shift (δ) from room temperature Mössbauer data clearly shows the presence of ferric (Fe3+) and Ti4+ ions illustrating strong ferromagnetic ordering up to x = 0.0206 in α-Fe2-xTixO3 hematite and weak ferromagnetic ordering of α-Fe2-xTixO3 for x = 0.0344.

Keywords:

magnetic materials, X-ray diffraction (XRD), Raman spectra, Mössbauer spectroscopy
Received: 10 May 2014 Revised: 20 June 2014 Accepted: 22 June 2014 Published: 30 November 2014 Issue date: December 2014
References(38)
[1]
Saragovi C, Arpe J, Sileo E, et al. Changes in the structural and magnetic properties of Ni-substituted hematite prepared from metal oxinates. Phys Chem Miner 2004, 31:625-632.
[2]
Van Van San E, De Grave E, Vandenberghe RE, et al. Study of Al-substituted hematites, prepared from thermal treatment of lepidocrocite. Phys Chem Miner 2001, 28:488-497.
[3]
Zysler RD, Fiorani D, Testa AM, et al. Size dependence of the spin-flop transition in hematite nanoparticles. Phys Rev B 2003, 68:212408.
[4]
Dang M-Z, Rancourt DG, Dutrizac JE, et al. Interplay of surface conditions, particle size, stoichiometry, cell parameters, and magnetism in synthetic hematite-like materials. Hyperfine Interact 1998, 117:271-319.
[5]
Bruzzone CL, Ingalls R. Mössbauer-effect study of the Morin transition and atomic positions in hematite under pressure. Phys Rev B 1983, 28:2430.
[6]
Hofmann M, Campbell SJ, Kaczmarek WA, et al. Mechanochemical transformation of α-Fe2O3 to Fe3-xO4—Microstructural investigation. J Alloys Compd 2003, 348:278-284.
[7]
Bersani D, Lottici PP, Montenero A. Micro-Raman investigation of iron oxide films and powders produced by sol–gel syntheses. J Raman Spectrosc 1999, 30:355-360.10.1002/(SICI)1097-4555(199905)30:5<355::AID-JRS398>3.0.CO;2-C
[8]
Shim S-H, Duffy TS. Raman spectroscopy of Fe2O3 to 62 GPa. Am Mineral 2001, 87:318-326.
[9]
Beattie IR, Gibson TR. The single-crystal Raman spectra of nearly opaque materials. Iron (III) oxide and chromium (III) oxide. J Chem Soc A 1970:980-986.
[10]
McCarty KF. Inelastic light scattering in α-Fe2O3: Phonon vs magnon scattering. Solid State Commun 1988, 68:799-802.
[11]
McCarty KF, Boehme DR. A Raman study of the systems Fe3−xCrxO4 and Fe2−xCrxO3. J Solid State Chem 1989, 79:19-27.
[12]
Zhao Y, Dunnill CW, Zhu Y, et al. Low-temperature magnetic properties of hematite nanorods. Chem Mater 2007, 19:916-921.
[13]
Bødker F, Hansen MF, Koch CB, et al. Magnetic properties of hematite nanoparticles. Phys Rev B 2000, 61:6826.
[14]
Rath C, Sahu KK, Kulkarmi SD, et al. Microstructure-dependent coercivity in monodispersed hematite particles. Appl Phys Lett 1999, 75:4171.
[15]
Gregg KA, Perera SC, Lawes G, et al. Controlled synthesis of MnP nanorods: Effect of shape anisotropy on magnetization. Chem Mater 2006, 18:879-886.
[16]
Hill AH, Jiao F, Bruce PG, et al. Neutron diffraction study of mesoporous and bulk hematite, α-Fe2O3. Chem Mater 2008, 20:4891-4899.
[17]
Ayub I, Berry FJ, Bilsborrow RL, et al. Influence of zinc doping on the structural and magnetic properties of α-Fe2O3. J Solid State Chem 2001, 156:408-414.
[18]
He T, Luo H-L, Li S. Effect of cobalt on the morin transition of hematite. J Magn Magn Mater 1988, 71:323-328.
[19]
Barrero CA, Arpe J, Sileo E, et al. Ni- and Zn-doped hematite obtained by combustion of mixed metal oxinates. Physica B 2004, 354:27-34.
[20]
Morrish AH. Canted Antiferromagnetism: Hematite. Singapore:World Scientific Publishing Company, 1994.
[21]
Stewart SJ, Borzi RA, Cabanillas ED, et al. Effects of milling-induced disorder on the lattice parameters and magnetic properties of hematite. J Magn Magn Mater 2003, 260:447-454.
[22]
Sileo EE, Daroca DP, Barrero CA, et al. Influence of the genesis on the structural and hyperfine properties of Cr-substituted hematites. Chem Geol 2007, 238:84-93.
[23]
Ericsson T, Krisnhamurthy A, Srivastava BK. Morin-transition in Ti-substituted hematite: A Mössbauer study. Phys Scr 1986, 33:88.
[24]
Yogi A, Varshney D. Cu doping effect of hematite (α-Fe2-xCuxO3): Effect on the structural and magnetic properties. Mat Sci Semicon Proc 2014, 21:38-44.
[25]
Yogi A, Varshney D. Magnetic and structural properties of pure and Cr-doped hematite: α-Fe2-xCrxO3 (0 ≤ x ≤ 1). J Adv Ceram 2013, 2:360-369.
[26]
Varshney D, Yogi A. Influence of Cr and Mn substitution on the structural and spectroscopic properties of doped hematite: α-Fe2-xMxO3 (0.0 < x < 0.50). J Mol Struct 2013 1052:105-111.10.1016/j.molstruc.2013.08.052
[27]
Varshney D, Yogi A. Structural, electrical and magnetoresistance of titanium-doped iron (II,III) oxide (Fe3O4) thin films deposited on strontium titanate, alumina, silicon, and float glass. Mat Sci Semicon Proc 2014, 26:33-40.
[28]
Varshney D, Yogi A. Structural and transport properties of stoichiometric and Cu2+-doped magnetite: Fe3-xCuxO4. Mater Chem Phys 2010, 123:434-438.
[29]
Varshney D, Yogi A. Structural and electrical conductivity of Mn doped hematite (α-Fe2O3) phase. J Mol Struct 2011, 995:157-162.
[30]
Varshney D, Yogi A. Structural and transport properties of stoichiometric Mn2+-doped magnetite: Fe3−xMnxO4. Mater Chem Phys 2011, 128:489-494.
[31]
Jiang Z, Liu Q, Barrón V, et al. Magnetic discrimination between Al-substituted hematites synthesized by hydrothermal and thermal dehydration methods and its geological significance. J Geophys Res: Sol Ea 2012, 117, .
[32]
Jiang Z, Rochette P, Liu Q, et al. Pressure demagnetization of synthetic Al substituted hematite and its implications for planetary studies. Phys Earth Planet In 2013, 224:1-10.
[33]
Lee MH, Park JH, Han HS, et al. Nanostructured Ti-doped hematite (α-Fe2O3) photoanodes for efficient photoelectrochemical water oxidation. Int J Hydrogen Energ 2013, .
[34]
Kumari S, Singh AP, Sonal, et al. Spray pyrolytically deposited nanoporous Ti4+ doped hematite thin films for efficient photo electrochemical splitting of water. Int J Hydrogen Energ 2010, 35:3985-3990.
[35]
Lian X, Yang X, Liu S, et al. Enhanced photoelectron-chemical performance of Ti-doped hematite thin films prepared by the sol–gel method. Appl Surf Sci 2012, 258:2307-2311.
[36]
Kleiman-Shwarsctein A, Hu Y-S, Stucky GD, et al. NiFe-oxide electrocatalysts for the oxygen evolution reaction on Ti doped hematite photoelectrodes. Electrochem Commun 2009, 11:1150-1153.
[37]
Ruebenbauer K, Birchall T. A computer programme for the evaluation of Mössbauer data. Hyperfine Interact 1979, 7:125-133.
[38]
Li L, Chu Y, Liu Y. Synthesis and characterization of ring-like α-Fe2O3. Nanotechnology 2007, 18:105603.
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Publication history

Received: 10 May 2014
Revised: 20 June 2014
Accepted: 22 June 2014
Published: 30 November 2014
Issue date: December 2014

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© The author(s) 2014

Acknowledgements

Authors are thankful to UGC-DAE CSR, Indore for providing characterization facilities.

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