Mixed-oxide nanostructures of the type xGd 2 O 3 -(1-x)α-Fe 2 O 3 (x=0.1, 0.3, 0.5 and 0.7) were synthesized by mechanochemical activation for ball milling times of 0, 2, 4, 8 and 12 hours. The systems were subsequently analyzed by M ӧ ssbauer spectroscopy, X-ray powder diffraction (XRPD), magnetic measurements and optical diffuse reflectance spectroscopy. The magnetic hyperfine field was studied as function of ball milling time for all sextets involved and found to be consistent with the formation of a limited solid solution in the systems investigated. The end-product was the gadolinium perovskite, represented by a doublet whose abundance was derived as function of the milling time. The XRPD patterns recorded for the equimolar composition were dominated by the diffraction peaks of GdFeO 3 after 12 hours of milling. The hysteresis loops were recorded at 300 and 5 K in an applied magnetic field of 5 T and were interpreted as a superposition of paramagnetic behavior of gadolinium oxide and weak ferromagnetic behavior of hematite and gadolinium perovskite. The Morin transition of hematite was inferred from zero-field-cooling-field-cooling (ZFC-FC) curves measured with a magnetic field of 200 Oe in the 5-300 K temperature range and was found to depend on the ball milling time. Optical diffuse reflectance spectra showed that the compounds were semiconductors with an optical band gap of 2.1 eV.
Iordanova, N., Dupuis, M. and Rosso, K.M. (2005) Charge Transport in Metal Oxides: A Theoretical Study of Hematite α-Fe2O3. Journal of Chemical Physics, 122, Article ID: 144305. https://doi.org/10.1063/1.1869492
Rozenberg, G.Kh., Dubrovinsky, L.S., Pasternak, M.P., Naaman, O., LeBihan, T. and Ahuja, R. (2002) High Pressure Structural Studies of Hematite Fe2O3. Physical Review B, 65, Article ID: 064112. https://doi.org/10.1103/PhysRevB.65.064112
Bergenmayer, W., Schweiger, H. and Wimmer, E. (2004) Ab Initio Thermodynamics of Oxide Surfaces: O2 on Fe2O3 (0001). Physical Review B, 69, Article ID: 195409. https://doi.org/10.1103/PhysRevB.69.195409
Zheng, Y., Cheng, Y., Wang, Y., Bao, F., Zhou, L., Wei, X., Zhang, Y. and Zheng, Q. (2006) Quasicubicαα-Fe2O3 Nanoparticles with Excellent Catalytic Performance. Journal of Physical Chemistry, 110, 3093-3097. https://doi.org/10.1021/jp056617q
Wu, C., Yin, P., Zhu, X., Yang, C.O. and Xie, Y. (2006) Synthesis of Hematite (α-Fe2O3) Nanorods: Diameter-Size and Shape Effects on Their Applications in Magnetism, Lithium Ion Battery, and Gas Sensors. Journal of Physical Chemistry B, 110, 17806-17812. https://doi.org/10.1021/jp0633906
Reddy, B.V., Rasouli, F., Hajaligol, M.R. and Khanna, S.N. (2004) Novel Mechanism for Oxidation of CO by Fe2O3 Clusters. Fuel, 83, 1537-1541. https://doi.org/10.1016/j.fuel.2003.12.015
Liu, J.Z. (1986) Morin Transition in Hematite Doped with Iridium Ions. Journal of Magnetism and Magnetic Materials, 54-57, 901-902. https://doi.org/10.1016/0304-8853(86)90305-7
Sanchez, C., Sieber, K.D. and Somorjai, G.A. (1988) The Photochemistry of Niobium Doped α-Fe2O3. Journal of Electroanalytical Chemistry, 252, 269-290. https://doi.org/10.1016/0022-0728(88)80216-X
Oliveira, L.C.A., Zaera, F., Lee, I., Lima, D.Q., Ramalho, T.C., Silva, A.C. and Fonseca, E.M.B. (2009) Nb-Doped Hematites for Decomposition of Isopropanol: Evidence of Surface Reactivity by In-Situ CO Adsorption. Applied Catalysis A, 368, 17-21. https://doi.org/10.1016/j.apcata.2009.08.001
Tilley, S.D., Cornuz, M., Sivula, K. and Gratzel, M. (2010) Light-Induced Water Splitting with Hematite: Improved Nanostructure and Iridium Oxide Catalysis. Angewandte Chemie, 49, 6405-6408. https://doi.org/10.1002/anie.201003110
Kleiman-Shwarsctein, A., Huda, M.N., Walsh, A., Yan, Y., Stucky, G.D., Hu, Y.S., Al-Jassim, M.M. and McFarland, E.W. (2010) Electrodeposited Aluminum-Doped α-Fe2O3 Photoelectrodes: Experiment and Theory. Chemistry of Materials, 22, 510-517. https://doi.org/10.1021/cm903135j
Glasscock, J.A., Barnes, P.R.F., Plumb, I.C. and Savvides, N. (2007) Enhancement of Photoelectrochemical Hydrogen Production from Hematite Thin Films by Introduction of Ti and Si. Journal of Physical Chemistry, 111, 16477-16488. https://doi.org/10.1021/jp074556l
Music, S., Ilakovac, V., Ristic, M. and Popovic, S. (1992) Formation of Oxide Phases in the System Fe2O3-Gd2O3. Journal of Materials Science, 27, 1011-1015. https://doi.org/10.1007/BF01197655
Music, S., Popovic, S., Czako-Nagy, I. and Gashi, F. (1993) Formation of Oxide Phases in the System Fe2O3-Gd2O3 Part II. Journal of Materials Science, 12, 869-873. https://doi.org/10.1007/BF00278001
Salikhov, S.V., Toleukhanova, S.K., Bordyuzhin, I.G. and Savchenko, A.G. (2019) Phase Composition and Magnetic Properties of Fe2O3-FeO-Gd2O3 Powders after High-Energy Ball Milling and Thermal Treatment. Bulletin of the Russian Academy of Sciences: Physics, 83, 1275-1281. https://doi.org/10.3103/S1062873819100186
Bandyopadhyay, A., Sharma, S., Nath, M., Karmakar, A., Kumari, K. and Sutradhar S. (2021) Dielectric Study and Magnetic Property Analysis of Gd2O3 Nanorods/Nanowire in Combination with Monte Carlo Simulation. Journal of Alloys and Compounds, 882, Article ID: 160720. https://doi.org/10.1016/j.jallcom.2021.160720
Patel, S.K.S., Dhak, P., Kim, M.K., Lee, J.H., Kim, M. and Kim, S.K. (2016) Structural and Magnetic Properties of Co-Doped Gd2O3 Nanorods. Journal of Magnetism and Magnetic Materials, 403, 155-160. https://doi.org/10.1016/j.jmmm.2015.11.093
Osaka, T., Takahashi, H., Sagayama, H., Yamasaki, Y. and Ishiwata, S. (2017) High-Pressure Synthesis of an Unusual Antiferromagnetic Metal CaCoO3 with GdFeO3-Type Perovskite Structure. Physical Review B, 95, Article ID: 224440. https://doi.org/10.1103/PhysRevB.95.224440
Paul, R., Sen, P. and Das, I. (2016) Effect of Morphology on the Magnetic Properties of Gd2O3 Nanotubes. Physica E, 80, 149-154. https://doi.org/10.1016/j.physe.2016.01.038
Ruffo, A., Mozzati, M.C., Albini, B., Galinetto, P. and Bini, M. (2020) Role of Non-Magnetic Dopants (Ca, Mg) in GdFeO3 Perovskite Nanoparticles Obtained by Different Synthetic Methods: Structural, Morphological and Magnetic Properties. Journal of Materials Science: Materials in Electronics, 31, 18263-18277. https://doi.org/10.1007/s10854-020-04374-8
Shah, J. and Kotnala, R.K. (2012) Room Temperature Magnetoelectric Coupling Enhancement in Mg-Substituted Polycrystalline GdFeO3. Scripta Materialia, 67, 316-319. https://doi.org/10.1016/j.scriptamat.2012.05.003
Wu, A., Wang, Z., Wang, B., Ban, X., Jiang, L., Xu, J., Yuan, S. and Cao, S. (2014) Crystal Growth and Magnetic Properties of GdFeO3 Crystals by Floating Zone Method. Solid State Communications, 185, 14-17. https://doi.org/10.1016/j.ssc.2014.01.011
Vandana, C.S. and Rudramadevi, B.H. (2019) Structural, Magnetic and Dielectric Properties of Cobalt Doped GdFeO3 Orthoferrites. Materials Research Express, 6, Article ID: 126126. https://doi.org/10.1088/2053-1591/ab768f
Paul, P., Prajapat, C.L., Rajarajan, A.K. and Chandrasekhar Rao, T.V. (2018) Low Temperature Magnetic Properties of GdFeO3. AIP Conference Proceedings, 1942, Article ID: 130029. https://doi.org/10.1063/1.5029099
Zhu, X.H., Xiao, X.B., Chen, X.R. and Liu, B.G. (2017) Electronic Structure, Magnetism and Optical Properties of Orthorhombic GdFeO3 from First Principles. RSC Advances, 7, 4054. https://doi.org/10.1039/C6RA25259A
Sorescu, M., Diamandescu, L., Sofronie, M., Pratt, C. and Jubeck, J. (2022) Mechanochemical Synthesis and Mӧssbauer Characterization of Neodymium Oxide-Hematite Magnetic Ceramic Nanoparticles: Phase Sequence and Recoilless Fraction. Materials Chemistry and Physics, 277, Article ID: 125511. https://doi.org/10.1016/j.matchemphys.2021.125511
Stroh, C., Tolea, F., Valeanu, M., Diamandescu, L., Xu, T. and Sorescu, M. (2015) Ruthenium Oxide-Hematite Magnetic Ceramics Nanostructures. Ceramics International, 41, 14367-14375. https://doi.org/10.1016/j.ceramint.2015.07.070
Tauc, J., Grigorovici, R. and Vancu, A. (1966) Optical Properties and Electronic Structure of Amorphous Germanium. Physica Status Solidi, 15, 627. https://doi.org/10.1002/pssb.19660150224
Mallick, P. and Dash, B.N. (2013) X-Ray Diffraction and UV-Visible Characterizations of α-Fe2O3 Nanoparticles Annealed at Different Temperature. Nanoscience and Nanotechnology, 3, 130-134.
Hussain, Z. (2021) Optical Band Gap, Oxidation Polarizability, Optical Basicity and Electronegativity Measurements of Silicate Glasses Using Ellipsometer and Abbe Refractometer. New Journal of Glass and Ceramics, 11, 1-33. https://doi.org/10.4236/njgc.2021.111001