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Journal Articles

Density Functional Theory (DFT)-based bonding analysis correlates ligand field strength with $$^{99}$$Ru M$"o$ssbauer parameters of ruthenium-nitrosyl complexes

Kaneko, Masashi; Kato, Akane*; Nakashima, Satoru*; Kitatsuji, Yoshihiro

Inorganic Chemistry, 58(20), p.14024 - 14033, 2019/10

We applied density functional theory calculations to ruthenium-nitrosyl complexes, which are known to exist in high-level radioactive waste, to give a theoretical correlation between $$^{99}$$Ru M$"o$ssbauer spectroscopic parameters ($$delta$$ and $$Delta$$$$E_{rm Q}$$) and ligand field strength ($$Delta$$$$_{rm o}$$) for the first time. The structures of the series of complexes, [Ru(NO)L$$_{5}$$] (L = Br$$^{-}$$, Cl$$^{-}$$, NH$$_{3}$$, CN$$^{-}$$), were modeled based on the corresponding single-crystal X-ray coordinates. The comparisons of the geometries and total energies between the different spin states suggested that the singlet spin state of [Ru(II)(NO$$^{+}$$)L$$_{5}$$] complexes were the most stable. The calculated results of both the $$delta$$ and $$Delta$$$$E_{rm Q}$$ values reproduced the experimental results by reported previously and increased in the order of L = Br$$^{-}$$, Cl$$^{-}$$, NH$$_{3}$$, CN$$^{-}$$. Finally, we estimated the ligand field strength ($$Delta$$$$_{rm o}$$) based on molecular orbitals, assuming C$$_{rm 4v}$$ symmetry and showed the increase of $$Delta$$$$_{rm o}$$ values in that order, being consistent with well-known spectrochemical series of ligands. The increase attributes to the strengthening of the abilities of $$sigma$$-donor and $$pi$$-acceptor of the L-ligands to the Ru atom, resulting in the increase of the $$delta$$ values.

Journal Articles

Proton chelating ligands drive improved chemical separations for rhodium

Narita, Hirokazu*; Nicolson, R. M.*; Motokawa, Ryuhei; Ito, Fumiyuki*; Morisaku, Kazuko*; Goto, Midori*; Tanaka, Mikiya*; Heller, W. T.*; Shiwaku, Hideaki; Yaita, Tsuyoshi; et al.

Inorganic Chemistry, 58(13), p.8720 - 8734, 2019/07

 Times Cited Count:0 Percentile:100(Chemistry, Inorganic & Nuclear)

Journal Articles

Ion hydration and association in an aqueous calcium chloride solution in the GPa range

Yamaguchi, Toshio*; Nishino, Masaaki*; Yoshida, Koji*; Takumi, Masaharu*; Nagata, Kiyofumi*; Hattori, Takanori

European Journal of Inorganic Chemistry, 2019(8), p.1170 - 1177, 2019/02

 Times Cited Count:1 Percentile:34.19(Chemistry, Inorganic & Nuclear)

Neutron diffraction measurements of an aqueous 2 mol dm$$^{-3}$$ CaCl$$_2$$ solutions in D$$_{2}$$O have been made at 1 GPa, 298 K as well as 0.1 MPa, 298 K. The experimental structure factors are subjected to Empirical Potential Structure Refinement (EPSR) modeling to reveal the ion hydration and association and solvent water at the atomic level. About seven water molecules surround Ca$$^{2+}$$ at the Ca-O and Ca-D distances of 2.44 ${AA}$ and 3.70 ${AA}$, respectively, at both pressures, suggesting no significant pressure effect on the cation hydration. On the other hand, the Cl$$^{-}$$ ion shows a drastic change in water oxygen coordination from 7 at 0.1 MPa to 14 at 1 GPa, accompanied by shortening of Cl-O distance from 3.18 ${AA}$ to 3.15 ${AA}$. However, the number of water hydrogen atoms around Cl$$^{-}$$ does not change significantly as 6.0 $$sim$$ 6.7 with shortening Cl-D distance from 2.22 to 2.18 ${AA}$ on compression. The pressure effect on the solvent water structure is also drastic as an increase in water oxygen atoms of 4.7 at the O-O distance of 2.79 ${AA}$ at 0.1 MPa to 10.3 at 2.85 ${AA}$ at 1 GPa. The number of water hydrogen atoms, however, does not change as 1.2 at the O-D distance of 1.74 ${AA}$ for both pressures, demonstrating the presence of the O$$cdots$$D hydrogen bonds which are significantly bent at 1 GPa at 298 K. This change of hydrogen bonds in water with pressure probably causes the drastic increase in water oxygen atoms around Cl$$^{-}$$.

Journal Articles

Theoretical elucidation of Am(III)/Cm(III) separation mechanism with diamide-type ligands using relativistic density functional theory calculation

Kaneko, Masashi; Suzuki, Hideya; Matsumura, Tatsuro

Inorganic Chemistry, 57(23), p.14513 - 14523, 2018/12

 Times Cited Count:2 Percentile:56.22(Chemistry, Inorganic & Nuclear)

We elucidated the separation mechanism between Am(III) and Cm(III) ions by using two different types of diamide ligands, diglycolamide (DGA) and alkylated diamide amine (ADAAM), by means of the density functional theory technique and electron density analysis. The molecular geometries and formation reactions of the metal-ligand complexes were modeled by using [M(DGA)$$_{3}$$]$$^{3+}$$ and [M(ADAAM)(NO$$_{3}$$)$$_{3}$$(H$$_{2}$$O)]. We successfully reproduced Cm(III) selectivity over Am(III) with DGA and Am(III) selectivity over Cm(III) with ADAAM. Furthermore, we analyzed the bonding properties between the metal ion and the diamide-type ligands by using model complexes, [M(DGA)$$_{3}$$]$$^{3+}$$ and [M(ADAAM)(NO$$_{3}$$)$$_{3}$$(H$$_{2}$$O)], and revealed the differences in terms of the bond dissociation energy and the metal 5f-orbital participation in the covalency between the Am(III) and the Cm(III) complexes. It was suggested that the differences were key factors to understand the Am(III)/Cm(III) selectivity.

Journal Articles

Synthesis, direct formation under high pressure, structure, and electronic properties of LiNbO$$_{3}$$-type oxide PbZnO$$_{3}$$

Mori, Daisuke*; Tanaka, Kie*; Saito, Hiroyuki; Kikegawa, Takumi*; Inaguma, Yoshiyuki*

Inorganic Chemistry, 54(23), p.11405 - 11410, 2015/12

 Times Cited Count:10 Percentile:34.61(Chemistry, Inorganic & Nuclear)

Journal Articles

Synthesis, structure, and pressure-induced polymerization of Li$$_{3}$$Fe(CN)$$_{6}$$ accompanied with enhanced conductivity

Li, K.*; Zheng, H.*; Hattori, Takanori; Sano, Asami; Tulk, C. A.*; Molaison, J.*; Feygenson, M.*; Ivanov, I. N.*; Yang, W.*; Mao, H.-K.*

Inorganic Chemistry, 54(23), p.11276 - 11282, 2015/12

 Times Cited Count:5 Percentile:59.5(Chemistry, Inorganic & Nuclear)

Pressure-induced polymerization of triple bonds would produce conductive conjugated double bonds. To find a metal cyanide with a low polymerization pressure, anhydrous Li$$_{3}$$Fe(CN)$$_{6}$$ is synthesized and its crystal structure is determined. The irreversible bonding between the CN$$^{-}$$ can be realized by use of the industrial apparatus. The conductivity is enhanced by more than 3 orders of magnitude, which makes the polymerized Li$$_{3}$$Fe(CN)$$_{6}$$ a potential cathode material for rechargeable lithium batteries.

Journal Articles

Crystal structures and magnetic properties of nickel chain compounds PbM$$_2$$Ni$$_6$$Te$$_3$$O$$_{18}$$ (M = Mn, Cd)

Doi, Yoshihiro*; Suzuki, Ryo*; Hinatsu, Yukio*; Kodama, Katsuaki; Igawa, Naoki

Inorganic Chemistry, 54(22), p.10725 - 10731, 2015/11

 Times Cited Count:1 Percentile:92.36(Chemistry, Inorganic & Nuclear)

Journal Articles

Synthesis, structure, luminescence, and magnetic properties of a single-ion magnet, "$$mer$$"-[Tris($$N$$-[(imidazol-4-yl)-methylidene]-DL-phenylalaninato)terbium(III) and related "$$fac$$"-DL-alaninato derivative

Yamauchi, Suguru*; Fujinami, Takeshi*; Matsumoto, Naohide*; Mochida, Naotaka*; Ishida, Takayuki*; Sunatsuki, Yukinari*; Watanabe, Masayuki; Tsuchimoto, Masanobu*; Coletti, C.*; Re, N.*

Inorganic Chemistry, 53(12), p.5961 - 5971, 2014/06

 Times Cited Count:12 Percentile:34.23(Chemistry, Inorganic & Nuclear)

Two Tb$$^{rm III}$$ complexes with same N$$_{6}$$O$$_{3}$$ donor atoms but different coordination geometries,${it "$fac$"}$-[Tb$$^{rm III}$$(HL$$^{rm DL-ala}$$)$$_{3}$$]7H$$_{2}$$O (${bf 1}$) and ${it "$mer$"}$-[Tb$$^{rm III}$$(HL$$^{rm DL-phe}$$)$$_{3}$$]7H$$_{2}$$O (${bf 2}$), were synthesized, where H$$_{2}$$L$$^{rm DL-ala}$$ and H$$_{2}$$L$$^{rm DL-phe}$$ are ${it N}$-[(imidazol-4-yl)methylidene]-DL-alanine and -DL-phenylalanine, respectively. The magnetic data were analyzed by a spin Hamiltonian including the crystal field effect on Tb$$^{rm III}$$ ion (4f$$^{8}$$, ${it J}$ = 6, ${it S}$ = 3, ${it L}$ = 3, ${it g$_{J}$}$ = 3/2, $$^{7}$$F$$_{6}$$). The Stark splitting of the ground state $$^{7}$$F$$_{6}$$ was evaluated from the magnetic analysis, and the energy diagram pattern indicated an easy-plane and easy-axis (Ising type) magnetic anisotropies for ${bf 1}$ and ${bf 2}$, respectively. Highly efficient luminescences with $$phi$$ = 0.50 and 0.61 for ${bf 1}$ and ${bf 2}$, respectively, were observed, and the luminescence fine structure due to the $$^{5}$$D$$_{4}$$ $$rightarrow$$ $$^{7}$$F$$_{6}$$ transition is in good accordance with the energy diagram determined from the magnetic analysis.

Journal Articles

Superheavy element flerovium (element 114) is a volatile metal

Yakushev, A.*; Gates, J. M.*; T$"u$rler, A.*; Sch$"a$del, M.; D$"u$llmann, Ch. E.*; Ackermann, D.*; Andersson, L.-L.*; Block, M.*; Br$"u$chle, W.*; Dvorak, J.*; et al.

Inorganic Chemistry, 53(3), p.1624 - 1629, 2014/02

 Times Cited Count:60 Percentile:1.55(Chemistry, Inorganic & Nuclear)

We report on a gas-solid chromatography study of the adsorption of element 114 (flerovium, Fl) on a Au surface. Fl was produced in the nuclear fusion reaction $$^{244}$$Pu($$^{48}$$Ca, 3-4n)$$^{288,289}$$Fl and was isolated in-flight from the primary $$^{48}$$ beam in a physical recoil separator. The adsorption behavior of Fl, its nuclear $$alpha$$-decay product Cn, their lighter homologues in groups 14 and 12, i.e., Pb and Hg, and the noble gas Rn were studied simultaneously by isothermal gas chromatography and thermochromatography. Two Fl atoms were detected. They adsorbed on a Au surface at room temperature, but not as readily as Pb and Hg. The observed adsorption behavior of Fl points to a higher inertness compared to its nearest homologue in the group, Pb. However, the measured lower limit for the adsorption enthalpy of Fl on a Au surface points to the formation of a metal-metal bond of Fl with Au. Fl is the least reactive element in the group, but still a metal.

Journal Articles

Magnetic structure and electromagnetic properties of LnCrAsO with a ZrCuSiAs-type structure (Ln = La, Ce, Pr, and Nd)

Park, S.-W.*; Mizoguchi, Hiroshi*; Kodama, Katsuaki; Shamoto, Shinichi; Otomo, Toshiya*; Matsuishi, Satoru*; Kamiya, Toshio*; Hosono, Hideo*

Inorganic Chemistry, 52(23), p.13363 - 13368, 2013/12

 Times Cited Count:13 Percentile:35.97(Chemistry, Inorganic & Nuclear)

Journal Articles

Measurement of the Md$$^{3+}$$/Md$$^{2+}$$ reduction potential studied with flow electrolytic chromatography

Toyoshima, Atsushi; Li, Z.*; Asai, Masato; Sato, Nozomi; Sato, Tetsuya; Kikuchi, Takahiro; Kaneya, Yusuke; Kitatsuji, Yoshihiro; Tsukada, Kazuaki; Nagame, Yuichiro; et al.

Inorganic Chemistry, 52(21), p.12311 - 12313, 2013/11

 Times Cited Count:5 Percentile:68.53(Chemistry, Inorganic & Nuclear)

The reduction behavior of mendelevium (Md) was studied using a flow electrolytic chromatography apparatus. By applying appropriate potentials on the chromatography column, the more stable Md$$^{3+}$$ is reduced to Md$$^{2+}$$. The reduction potential of the Md$$^{3+}$$ + e$$^{-}$$ $$rightarrow$$ Md$$^{2+}$$ couple was determined to be -0.16$$pm$$0.05 V vs. a normal hydrogen electrode.

Journal Articles

Direct interactions between Z-DNA and alkaline earth cations, discovered in the presence of high concentrations of MgCl$$_{2}$$ and CaCl$$_{2}$$

Chatake, Toshiyuki*; Sunami, Tomoko

Journal of Inorganic Biochemistry, 124, p.15 - 25, 2013/07

 Times Cited Count:8 Percentile:53.68(Biochemistry & Molecular Biology)

Journal Articles

Rapid synthesis of radioactive transition-metal carbonyl complexes at ambient conditions

Even, J.*; Yakushev, A.*; D$"u$llmann, C. E.*; Dvorak, J.*; Eichler, R.*; Gothe, O.*; Hild, D.*; J$"a$ger, E.*; Khuyagbaatar, J.*; Kratz, J. V.*; et al.

Inorganic Chemistry, 51(12), p.6431 - 6433, 2012/06

 Times Cited Count:25 Percentile:19(Chemistry, Inorganic & Nuclear)

Carbonyl complexes of radioactive transition metals can be easily synthesized with high yields by stopping nuclear fission or fusion products in a gas volume containing CO. Here, we focus on Mo, W, and Os complexes. The reaction takes place at pressures of around 1 bar at room temperature, i.e., at conditions that are easy to accommodate. The formed complexes are highly volatile. They can thus be transported within a gas stream without major losses to setups for their further investigation or direct use. The rapid synthesis holds promise for radiochemical purposes and will be useful for studying, e.g., chemical properties of superheavy elements.

Journal Articles

Structural study on 2,2'-(methylimino)bis($$N$$,$$N$$-dioctylacetamide) complex with Re(VII)O$$_{4}$$$$^{-}$$ and Tc(VII)O$$_{4}$$$$^{-}$$ by $$^{1}$$H-NMR, EXAFS and IR spectroscopy

Saeki, Morihisa; Sasaki, Yuji; Nakai, Ayaka*; Ohashi, Akira*; Banerjee, D.*; Scheinost, A. C.*; Foerstendorf, H.*

Inorganic Chemistry, 51(10), p.5814 - 5821, 2012/05

 Times Cited Count:19 Percentile:29.33(Chemistry, Inorganic & Nuclear)

The structures of the complex of 2,2'-(methylimino)bis($$N$$,$$N$$-dioctylacetamide) (MIDOA) with M(VII)O$$_{4}$$$$^{-}$$ (M=Re and Tc), which were prepared by liquid-liquid solvent extraction, were investigated by using $$^{1}$$H-NMR, EXAFS and IR spectroscopy. The results from $$^{1}$$H-NMR and EXAFS provide therefore evidence of M(VII)O$$_{4}$$$$^{-}$$...H$$^{+}$$MIDOA complex formation in the organic solution. The IR spectra of Re(VII)O$$_{4}$$$$^{-}$$...H$$^{+}$$MIDOA and Tc(VII)O$$_{4}$$$$^{-}$$...H$$^{+}$$MIDOA were analyzed based on the structures and the IR spectra calculated at the B3LYP/cc-pVDZ level. Comparison of the observed and calculated IR spectra demonstrates that an intramolecular hydrogen bond is formed in H$$^{+}$$MIDOA and the M(VII)O$$_{4}$$$$^{-}$$ ion interact with H$$^{+}$$MIDOA through multiple C-H$$_{n}$$...O hydrogen bonds.

Journal Articles

Antiferromagnetic interaction between A'-site Mn spins in A-site-ordered perovskite YMn$$_3$$Al$$_4$$O$$_{12}$$

Toyama, Takenori*; Saito, Takashi*; Mizumaki, Masaichiro*; Agui, Akane; Shimakawa, Yuichi*

Inorganic Chemistry, 49(5), p.2492 - 2495, 2010/01

 Times Cited Count:20 Percentile:29.52(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Neptunium carbonato complexes in aqueous solution; An Electrochemical, spectroscopic, and quantum chemical study

Ikeda, Atsushi; Tsushima, Satoru*; Takao, Koichiro*; Rossberg, A.*; Funke, H.*; Scheinost, A. C.*; Bernhard, G.*; Yaita, Tsuyoshi; Hennig, C.*

Inorganic Chemistry, 48(24), p.11779 - 11787, 2009/12

 Times Cited Count:25 Percentile:25.57(Chemistry, Inorganic & Nuclear)

The electrochemical behavior and complex structure of Np carbonato complexes have been investigated in aqueous Na$$_{2}$$CO$$_{3}$$ and Na$$_{2}$$CO$$_{3}$$/NaOH solutions at different oxidation states by using cyclic voltammetry, X-ray absorption spectroscopy, and density functional theory calculations. The end-member complexes of penta- and hexavalent Np in 1.5 M Na$$_{2}$$CO$$_{3}$$ with pH = 11.7 have been determined as a transdioxo neptunyl tricarbonato complex, [NpO$$_{2}$$(CO$$_{3}$$)$$_{3}$$]$$^{n-}$$ ($$n$$ = 5 for Np$$^{rm V}$$, and 4 for Np$$^{rm VI}$$). In contrast, the electrochemical oxidation of Np$$^{rm V}$$ in a highly basic carbonate solution of 2.0M Na$$_{2}$$CO$$_{3}$$/1.0M NaOH (pH $$>$$ 13) yielded a stable heptavalent Np complex of [Np$$^{rm VII}$$ O$$_{4}$$(OH)$$_{2}$$]$$^{3-}$$, indicating that the oxidation reaction from Np$$^{rm V}$$ to Np$$^{rm VII}$$ in the carbonate solution involves a drastic structural rearrangement from the transdioxo configuration to a square-planar-tetraoxo configuration, as well as exchanging the coordinating anions from carbonate ions (CO$$_{3}$$$$^{2-}$$) to hydroxide ions (OH$$^{-}$$).

Journal Articles

Speciation and structural study of U(IV) and -(VI) in perchloric and nitric acid solutions

Ikeda, Atsushi; Hennig, C.*; Tsushima, Satoru*; Scheinost, A. C.*; Bernhard, G.*; Yaita, Tsuyoshi

Inorganic Chemistry, 48(15), p.7201 - 7210, 2009/07

 Times Cited Count:58 Percentile:5.73(Chemistry, Inorganic & Nuclear)

Speciation and complex structure of U(IV) and U(VI) are studied in aqueous acidic solutions of HClO$$_{4}$$ and HNO$$_{3}$$ by means of UV-visible-NIR and X-ray absorption spectroscopies, and density functional theory (DFT) calculations. A spherical coordinating tetravalent cation of U$$^{4+}$$ is surrounded by 9-10 water molecules in the primary coordination sphere in 1.0 M HClO$$_{4}$$, while it forms a not-well-ordered colloidal compound of UO$$_{rm 2+x}$$ (x = 0.2) mixture in a lower acidic concentration of 0.1 M HClO$$_{4}$$. U(VI) exists as a transdioxo uranyl cation, UO$$_{2}$$$$^{2+}$$, and forms a 5-fold pure hydrate complex of [UO$$_{2}$$(H$$_{2}$$O)$$_{5}$$]$$^{2+}$$ in 1.0 M HClO$$_{4}$$. The water molecules in the pure hydrate complexes of U(IV) and U(VI) are successively replaced by planar bidentate coordinate nitrate ions (NO$$_{3}$$$$^{-}$$) as a function of increasing HNO$$_{3}$$ concentration. The presence of unidentate coordinate nitrate complexes or tetranitrato U(VI) complexes is less probable in the present HNO$$_{3}$$ system.

Journal Articles

The Sulfate coordination of Np(IV), Np(V), and Np(VI) in aqueous solution

Hennig, C.*; Ikeda, Atsushi; Tsushima, Satoru*; Scheinost, A. C.*

Inorganic Chemistry, 48(12), p.5350 - 5360, 2009/06

 Times Cited Count:36 Percentile:14.25(Chemistry, Inorganic & Nuclear)

Coordination and redox behavior of Np(IV), Np(V) and Np(VI) sulfate in aqueous solution has been investigated by Np L3-edge extended X-ray absorption fine structure (EXAFS) spectroscopy, cyclic voltammetry and density functional theory (DFT) calculations. TNp(VI) is coordinated by sulfate in bidentate (RNp-S = 3.12 A) and monodentate (RNp-S = 3.61 A) modes at a low sulfate concentration of [SO$$_{4}$$$$^{2-}$$]/[NpO$$_{2}$$$$^{2+}$$] = 1. At higher [SO$$_{4}$$$$^{2-}$$]/[NpO$$_{2}$$$$^{2+}$$] ratios bidentate coordination prevails. Approximately two bidentate sulfate groups are coordinated to Np(VI) at 2.0 M SO$$_{4}$$$$^{2-}$$ and pH 1.1. Np(V) is coordinated by sulfate in bidentate (RNp-S = 3.16 A) and monodentate (RNp-S = 3.67 A) modes. However, sulfate coordination is less pronounced here and does not exceed in total one SO$$_{4}$$$$^{2-}$$ ligand in a solution of 2.0 M SO$$_{4}$$$$^{2-}$$. The redox couple Np(VI)/Np(V) is reversible at low [SO$$_{4}$$$$^{2-}$$]/[NpO$$_{2}$$$$^{2+}$$] ratio and becomes irreversible at high sulfate concentration due to structural rearrangement of the sulfate ligands.

Journal Articles

Electrochemical and complexation behavior of neptunium in aqueous perchlorate and nitrate solutions

Ikeda, Atsushi; Hennig, C.*; Rossberg, A.*; Funke, H.*; Scheinost, A. C.*; Bernhard, G.*; Yaita, Tsuyoshi

Inorganic Chemistry, 47(18), p.8294 - 8305, 2008/09

 Times Cited Count:55 Percentile:40.97(Chemistry, Inorganic & Nuclear)

Electrochemical and complexation properties of neptunium (Np) are investigated in aqueous perchlorate and nitrate solutions by means of cyclic voltammetry, bulk electrolysis, UV-visible absorption and Np L$$_{rm III}$$-edge X-ray absorption spectroscopies. The redox reactions of Np(III)/Np(IV) and Np(V)/Np(VI) couples are reversible or quasi-reversible, while the electrochemical reaction between Np(III/IV) and Np(V/VI) is irreversible because they undergo the structural rearrangement from spherical coordinating ions (Np$$^{3+}$$ and Np$$^{4+}$$) to transdioxo neptunyl ions (NpO$$_{2}$$$$^{n+}$$, n = 1 for Np(V) and 2 for Np(VI)). A detailed analysis on extended X-ray absorption fine structure (EXAFS) spectra suggests that Np(IV) forms a decaaquo complex of [Np(H$$_{2}$$O)$$_{10}$$]$$^{4+}$$ in 1.0 M HClO$$_{4}$$, while Np(V) and -(VI) exist dominantly as pentaaquo neptunyl complexes, [NpO$$_{2}$$(H$$_{2}$$O)$$_{5}$$]$$^{n+}$$ (n = 1 for Np(V) and 2 for Np(VI)).

Journal Articles

Magnetic and dielectric properties of InFe$$_{2}$$O$$_{4}$$, InFeCuO$$_{4}$$, and InGaCuO$$_{4}$$

Yoshii, Kenji; Ikeda, Naoshi*; Okajima, Yuka; Yoneda, Yasuhiro; Matsuo, Yoji*; Horibe, Yoichi*; Mori, Shigeo*

Inorganic Chemistry, 47(14), p.6493 - 6501, 2008/07

 Times Cited Count:24 Percentile:26.63(Chemistry, Inorganic & Nuclear)

The magnetic and dielectric properties of InFe$$_{2}$$O$$_{4}$$, InFeCuO$$_{4}$$and InGaCuO$$_{4}$$ have been investigated. All these materials areisostructural with RFe$$_{2}$$O$$_{4}$$ (R=Y, Ho-Lu), which shows ferroelectricity due to iron-valence ordering. InFe$$_{2}$$O$$_{4}$$ exhibits similar properties to those of RFe$$_{2}$$O$$_{4}$$; the origins of the magnetic and dielectric phenomena are likely common in InFe$$_{2}$$O$$_{4}$$ and RFe$$_{2}$$O$$_{4}$$. From measurements of the other two materials, we found that both the magnetic transition temperature and the dielectric constant are decreased in the order of InFe$$_{2}$$O$$_{4}$$, InFeCuO$$_{4}$$ and InGaCuO$$_{4}$$. This result strongly supports the previously reported explanation based on an electron transfer between the Fe-site ions for the corresponding rare-earth systems. Therefore, we propose that the dielectric properties of the oxides isostructural with RFe$$_{2}$$O$$_{4}$$ are plausibly governed by electron transfer; this situation is different from that of ordinary ferroelectrics and dielectrics, in which the displacement factions and anions is important. In addition, InFeCuO$$_{4}$$ and InGaCuO$$_{4}$$ exhibit large dielectric constants (larger than about 1500). Inconsideration of this property, the possible applications of these oxides are discussed.

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