Features of Synthesis and Magnetic Characteristics of Yttrium Orthoferrite Produced by Gel Combustion
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HESIS AND PROPERTIES OF INORGANIC COMPOUNDS
Features of Synthesis and Magnetic Characteristics of Yttrium Orthoferrite Produced by Gel Combustion V. A. Ketskoa, *, M. N. Smirnovaa, M. A. Kop’evaa, G. E. Nikiforovaa, A. A. Geras’kinb, and K. I. Yanushkevichc aKurnakov
Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow, 119991 Russia b MIREA Russian Technological University, Moscow, 119454 Russia c Brovka Materials Science Applied Research Center, National Academy of Belarus, Minsk, 220072 Belarus *e-mail: [email protected] Received April 9, 2020; revised April 17, 2020; accepted April 27, 2020
Abstract—The effect of an organic fuel on the combustion mode, features of combustion, and the phase composition of the end product of the synthesis of yttrium orthoferrite was studied. It was shown that the production of YFeO3 requires a fuel that favors the formation of a single polymer metal-containing complex determining the gel structure and ensures the combustion in an intense self-sustaining mode. Yttrium orthoferrite was synthesized by gel combustion using a mixture of citric acid and ammonium nitrate as a fuel. The unit cell parameters of orthorhombic (space group Pnma) yttrium orthoferrite were found to be a = 5.594(2) Å, b = 7.604(3) Å, c = 5.282(1) Å, and V = 224.7(3) Å3. The temperature dependence of the specific magnetization of YFeO3 in the range 80–800 K was investigated. The temperature of the magnetic phase transformation magnetic order–magnetic disorder was determined to be TC ~ 620 K. Keywords: glycine, citric acid, morphology, magnetic properties DOI: 10.1134/S0036023620090065
INTRODUCTION Orthoferrites are a class of chemical compounds with the general formula RFeO3 (R is a rare-earth element), which is widely used in various areas of science and technology [1–6]. Most rare-earth element orthoferrites have a perovskite-like crystal structure, which determines features of their physicochemical properties [5, 6]. Because of orthorhombic distortions of the crystal structure, orthoferrites are characterized by high mobility (~1 m2/(s A)) and velocity (~20 km/s) of domain boundaries [7, 8]. The saturation magnetization of orthoferrites is ∼20 times lower than that of garnet ferrites [9]. Orthoferrite YFeO3 has a variety of important practical properties. Depending on features of the crystal order, it can be a multiferroic, semiconductor, and photocatalyst in the visible region [6, 9]. Orthoferrite YFeO3 crystallizes in a distorted perovskite structure and has an orthorhombic unit cell in which iron ions are surrounded by six oxygen atoms to form octahedra. Depending on the degree of distortion of FeO6 octahedra, yttrium orthoferrite is characterized by antiferromagnetic order of magnetic moments or exhibits properties of a weak ferromagnet [9].
It is known that yttrium orthoferrite can be obtained by solid-phase synthesis [3, 5, 6], hydrothermal method [2, 10–12], and sol–gel process [13]. The production of nanosized yttrium orthoferrite by a classical method of solid-phase r
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