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A low temperature, one-pot route to iron-doped rare-earth chromite perovskite was proposed. Fe half-doped rare-earth chromites, REFe0.5Cr0.5O3 (RE = La, Tb, Ho, Er, Yb, Lu and Y) were prepared via a mild hydrothermal method and their magnetic properties were studied. All of these materials are well-crystallized and the profile refinement of powder X-ray diffraction (XRD) data showed that each of them adopts an orthorhombic distorted (Pbnm) perovskite structure. The temperature dependence of the magnetization curves indicate an improved order of arrangement of Fe3+ and Cr3+ at the B-site in some samples. Hysteresis measurements of YFe0.5Cr0.5O3 indicate that saturated and remnant magnetization were improved greatly compared to that prepared via the solid state method. [ABSTRACT FROM AUTHOR]

Five coordination polymers, Mn4(nbpdc)4(bip)(H2O)2(1), Co5(nbpdc)4(bip)2(H2O)6(OH)2(2), Cu5(nbpdc)4(bip)2(H2O)2(OH)2(3), Zn5(nbpdc)4(bip)2(OH)2(4), and Cd2(nbpdc)2(bip) (5), (H2nbpdc = 2,2′-dinitro-4,4′-biphenyldicarboxyl acid, bip = 1,5-bis(imidazole)pentane), have been prepared and structurally characterized. In these compounds, nbpdc and bip link different secondary building units (SBUs) to construct a variety of architectures based on different metals. Compound 1presents a 3D hex net based on infinite rod-shaped SBUs. Compound 2shows a 3D framework with mab topology based on Co5clusters and exhibits an interesting self-penetration feature. Compound 3presents a 3D framework with pcu topology constructed by Cu5clusters. Compound 4is a 3D framework with pcu topology based on infinite rod-shaped SBUs. Compound 5, like compound 4, also exhibits pcu topology constructed by rod-shaped SBUs, but they both possess different structures. The magnetic properties of compounds 1and 2have been characterized. [ABSTRACT FROM AUTHOR]

Abstract: A green chemistry strategy was developed to prepare two barium copper silicate pigments. Chinese purple BaCuSi2O6 and dark blue BaCu2Si2O7 are synthesized through mild hydrothermal treatment in narrow pH range. The compounds are characterized by powder X-ray diffraction techniques, infrared spectroscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, luminance and magnetic measurements. When excited by a visible laser, hydrothermally synthetic BaCuSi2O6 exhibits a broad emission in the near-infrared region with an excited state lifetime 6.4 μs due to the square-planar Cu2+ ions as the chromophores. Magnetic analysis of BaCuSi2O6 indicates the spin gapped antiferromagnetic property due the presence of the Cu–Cu dimers in the structure. BaCu2Si2O7 shows interesting quasi-one-dimensional antiferromagnetic property. [Copyright &y& Elsevier]

Abstract: The magnetic and electron transport properties of rhombohedral Li x V y O2 (x=0.8 and y=0.8) are studied. The dc susceptibility of Li x V y O2 can be well fitted to the modified Curie–Weiss law, which verified the paramagnetic ground state. The magnetic hysteresis and ac susceptibility also confirm this paramagnetism. The Li x V y O2 exhibits semiconducting behavior, which is explained by thermal activated process at high temperature and variable-range hopping mechanism at low temperature. Anderson localization plays an important role in both the electron transport behavior and the magnetic behavior due to the site disorder between the Li+ ion and V4+ ion. [Copyright &y& Elsevier]

Abstract: Nanocrystalline Co/N thin film containing Co4N phase has been deposited on Si (111) substrate by direct current magnetron sputtering in 10% N2/N2 +Ar discharge. The composition, structure and magnetic properties were examined by X-ray photoelectron spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and superconducting quantum interference device. XRD and TEM investigations showed that the grain size of nanocrystalline Co4N was in the range 10–25nm (with the error of ±0.2nm). Magnetic analysis indicated that the synthesized Co/N thin films had good in-plane anisotropy. The value of H c with the domination orientation (111) was about 97Oe. The saturation magnetization was estimated to be 103.9±6.1emu/g, which was larger than the value of 46.5emu/g firstly reported by Oda et al. [Copyright &y& Elsevier]

Abstract: Y3−x−y Ce x Gd y Fe5O12 (x =0–0.1, y =0–1.0) nanoparticles were fabricated by a sol–gel method. The crystalline structures and magnetic properties of samples were investigated by X-ray diffraction (XRD), scanning probe microscopy (SPM), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometer (VSM). The XRD patterns of Y3−x−y Ce x Gd y Fe5O12 have only peaks of the garnet structure and the mean size range from 42 to 65nm. The particle''s size observed for all the samples analyzed by SPM are in good agreement with these data from XRD. The particle''s size ranged from 50 to 70nm, at the same time, there are small amount of reunited particles can be observed. XPS for Y2.9Ce0.1Fe5O12 gives two peaks at 885.15 and 905.15eV attributing to Ce3+3d5/2 and 3d3/2, respectively. The results confirm the valence state of Ce atoms being +3. Results of VSM show that the saturation magnetization is increased with increasing Ce content (x) and is decreased with increasing the Gd concentration (y) in a linear manner. The saturation magnetization is increased with increasing the particle''s size. [Copyright &y& Elsevier]

Abstract: RMn2O5 (R=La, Pr, Nd, Tb, Bi) crystallites were prepared by a mild hydrothermal method and characterized by powder X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and magnetic measurement. The formation of manganates was sensitive to the alkalinities and Mn-containing precursors of the reaction mixtures. This family of manganates is isostructural and has a space group of Pbam. The magnetic measurements for RMn2O5 showed an antiferromagnetic transition. The strong irreversibility between the ZFC and FC curves indicated a helicoidally magnetic structure below 40K. The max d.c. susceptibilities of LaMn2O5+ δ (δ=0.01, 0.06, 0.08, 0.16, 0.17) were found to be variable and the excess oxygen (δ) in the compounds was influenced by the alkalinity used in the hydrothermal synthesis. [Copyright &y& Elsevier]

Abstract: The metal–ferrite composites Fe x Co1− x /Co y Fe1− y Fe2O4 are synthesized by using disproportion of Fe(α) and reduction of Co(α) by Fe0 in a concentrated and boiling KOH solution. The structures and magnetic properties are investigated by XRD and VSM. XRD shows that the samples without calcinations contain b.c.c, f.c.c and spinel structures; the samples with 300°C calcinations contain b.c.c and spinel structures; and the samples with 500°C calcinations contain f.c.c and spinel structures. Magnetic measurement shows that the sample with Co/Fe=0.9 and without calcinations has the maximal coercive field of 2504.44Oe and the sample with Co/Fe=0.3 and without calcinations has the maximal saturation magnetization of 94.69emu/g corresponding to the maximal remnant magnetization of 28.47emu/g. [Copyright &y& Elsevier]

Abstract: Mössbauer spectra and magnetic measurement of Ni0.7Mn0.3Gd0.1Fe1.9O4 ferrite were investigated by Oxford MS-500 Mössbauer spectrometer and superconducting quantum interference device (SQUID) magnetometer with a field 5T. Ni0.7Mn0.3Gd0.1Fe1.9O4 nanoparticles have a considerable coercivity of 1040Oe when the test temperature is reduced to 2K. Mössbauer spectra show that Ni0.7Mn0.3Gd0.1Fe1.9O4 nanoparticles exhibit superparamagnetism at room temperature and ferrimagnetism at 77K. [Copyright &y& Elsevier]

Abstract: Dy3+-substituted garnet nanoparticles Y3− x Dy x Fe5O12 (, 0.2, 0.4, 0.6, 0.8 and 1.0) were fabricated by a sol–gel method and their crystalline structures and magnetic properties were investigated by using X-ray diffraction (XRD), infrared spectroscopy and vibrating sample magnetometer (VSM). The XRD patterns of Y3− x Dy x Fe5O12 have only peaks of the garnet structure and the sizes of particles range from 37 to 63nm. Results of VSM show that the saturation magnetization of Y3− x Dy x Fe5O12 () particles is not only obviously less than pure Yttrium iron garnet, but also decreases with increasing the Dy concentration (x) in a linear manner. Meanwhile, it is observed that with the enhancement of the surface spin effects, the saturation magnetization rises as the particle size is increased. [Copyright &y& Elsevier]

Abstract: The effects of rare-earth ions with different radii and magnetic moments on the magnetic properties of Ni–Mn ferrite are investigated. X-ray diffraction pattern has shown the presence of cubic structure of spinel ferrite for all samples. The values of M s and H c are decreasing with increasing of testing temperatures for all samples. The H c value of Ni0.7Mn0.3La0.1Fe1.9O4 reaches 1082Oe at 2K. Mössbauer spectra tested at 273K indicate the presence of superparamagnetism for samples calcined at 873K. [Copyright &y& Elsevier]

Abstract: Gd x BiY2−x Fe5O12 (x =0, 0.1, 0.2, 0.4, 0.6, 0.8) nanocrystals were synthesized by sol–gel method. Samples were characterized by using of X-ray diffraction (XRD), thermal gravity analysis (TGA), differential thermal analysis (DTA), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM).The average size of the particles was calculated by Scherrer''s formula from XRD data, which are from 43 to 50 nm. The effect of Gd3+ substitution for Y3+ on magnetic properties of BiY2Fe5O12 has been investigated. [Copyright &y& Elsevier]

Abstract: Gd3+-substituted garnet nanoparticles Y3− x Gd x Fe5O12 (, 0.2, 0.4, 0.6, 0.8 and 1.0) were fabricated by a sol–gel method and their crystalline structures and magnetic properties were investigated by using X-ray diffraction (XRD), IR spectroscopy and vibrating sample magnetometer (VSM). The XRD patterns of Y3− x Gd x Fe5O12 have only peaks of the garnet structure and the sizes of particles range from 34 to 67nm. Results of VSM show that the special saturation magnetization of Y3− x Gd x Fe5O12 () particles are not only obviously less than pure YIG, but also decrease with increasing Gd concentration (x) in a linear manner. Meanwhile, it is observed that with the enhancement of the surface spin effects, the saturation magnetization rises as the particle size is increased. [Copyright &y& Elsevier]

Abstract: The magnetic properties of nanocrystalline CoLa0.08Fe1.92O4 powders prepared by the emulsion method at room temperature have been studied by vibrating sample magnetometer (VSM). The structure and specific surface area were studied by X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET). The particle size of the powders varied from 13.3 to 264.2nm by changing the calcinations temperatures and the corresponding specific saturation magnetization () ranged from 48.8 to 78.4emu/g. On increasing the particle size, the coercivity () first increased, passed through a maximum and then dropped. At room temperature, the nanocrystalline CoLa0.08Fe1.92O4 powders with a crystallite size of 63.6nm achieved a desirable value of . A non-magnetic layer with the thickness of 1.1nm exists at the surface of the particles. [Copyright &y& Elsevier]

Abstract: Composites of α-Fe/Fe3O4 having dimensions in the range of 100–150nm have been prepared by disproportion method. The structure and morphology are investigated by XRD and TEM. XRD shows that the metal has got the BCC structure. TEM shows balls of metallic iron about 100-nm-wide stuck to magnetite grains. Magnetic measurement shows that the sample aged for 3h and calcined at 200°C has the maximal saturation magnetization corresponding to the highest concentration of α-Fe in the final sample. [Copyright &y& Elsevier]

Abstract: Two new copper coordination polymers generated from mixed organic ligands 4,4′-bipydine and 1,2,4-benzenetricarboxylate [Cu3(1,2,4-BTC)2(4,4′-bipy)(H2O)4] 1 and [Cu(1,2,4-HBTC)(4,4′-bipy)] 2 (1,2,4-BTC=1,2,4-benzenetricarboxylate) have been prepared hydrothermally and characterized by single crystal X-ray diffraction. Compound 1 crystallizes in the noncentrosymmetric space group , with , , , , and . Its structure contains two different one-dimensional (1-D) chains for the Cu ions, namely and ; the carboxylate of 1,2,4-BTC ligands links the two different 1-D chains into an interesting steplike neutral framework. Compound 2 crystallizes in the monoclinic space group , with , , , , , . Its structure contains novel paddle-wheel clusters Cu2(CO2)4(4,4′-bipy)2 as SBUs which are further linked by monoprotonated 1,2,4-BTC ligands into a 2-D neutral framework. The magnetic behaviors of both compounds have been studied. [Copyright &y& Elsevier]

Abstract: A layered vanadium selenite, (C4N2H12)0.5[(VO)2(H2O)2(SeO3)2(HSeO3)], has been hydrothermally synthesized and structurally characterized. Its structure is layered and can be described as vanadium selenite oxide layers with diprotonated piperazine occupying the interlayer space. The result of magnetic measurement for the title compound shows a typical antiferromagnetic interaction at low temperature. [Copyright &y& Elsevier]

Abstract: A three-dimensional iron phosphite, , has been synthesized under mild hydrothermal conditions and characterized by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P21/c, with unit cell parameters, a =12.4397(3)Å, b =10.1642(3)Å, c =9.3201(3)Å, and Z =4. The compound forms three-dimensional framework with six-membered channels along the c-axis. The Fe center in the framework adopts slightly distorted octahedral coordination geometry and is bridged by the pseudo-pyramidal phosphites. Magnetic measurement indicates the anti-ferromagnetic interactions in the title compound. [Copyright &y& Elsevier]

Nanocrystalline Ni0.7Mn0.3NdxFe2–xO4 ferrites with x values ranging from 0.00 to 0.10, in step of 0.02, have been prepared by the emulsion method. The structure and the morphology of ferrite nanoparticles were measured using X-ray diffractometer (XRD), transmission electron microscope (TEM) and Mössbauer spectra. It is shown that the structure of Ni0.7Mn0.3NdxFe2–xO4 ferrites nanoparticles is single spinel structure. The average crystallite sizes of the samples calculated using Scherrer'' relationship are almost identical with the observed diameter from the image of TEM. The magnetic properties of the samples were tested by a vibrating sample magnetometer (VSM) at room temperature. The nanoparticles of the samples have superparamagnetism when particle sizes are about 10 nm. [Copyright &y& Elsevier]

Two iron diphosphonates, [NH3(CH2)2NH3][FeII{HO3PC (CH3)(OH)(PO3H)}2] ·2H2O (1) and [NH3(CH2)2NH2(CH2)2 NH3][FeIII{O3PC(CH3)(OH)(PO3H)}2]·H2O (2), have been synthesized under hydrothermal conditions. Crystal data: 1, monoclinic, C2/c, a=24.754(5), b=5.331(1), c=16.010(3) A˚, β=117.787(3)°, V=1868.9(6) A˚3, Z=4, R1=0.0321; 2, orthorhombic, Pbcn, a=22.128(4), b=9.9479(9), c=19.110(2) A˚, V=4206.7(9) A˚3, Z=8, R1=0.0389. Both show chain structures in which anionic chains of [FeII{HO3PC(CH3)(OH) (PO3H)}2]n2n − in 1 or [FeIII{O3PC(CH3)(OH)(PO3H)}2]n3n− in 2 are composed of {FeIIO6} or {FeIIIO6} octahedra and {CPO3} tetrahedra alternatively. The protonated organic amines and lattice water are located between the chains with extensive hydrogen bonding interactions. Weak antiferromagnetic exchange couplings are propagated between the magnetic centers through the O–P–O bridges in both cases. [ABSTRACT FROM AUTHOR]

Abstract: A dinuclear oxovanadium compound [V2O2(l-his)2(2,2′-bipy)2]·[C2H6O2 ·(2,2′-bipy)] was synthesized under hydrothermal condition and characterized by single-crystal X-ray diffraction. X-ray crystallography revealed that each vanadium center is six coordinated and adopts a distorted octahedral structure. IR spectroscopy, ESR spectrum and magnetic susceptibility data for this compound are given. X-band ESR spectroscopy of the sample indicated the existence of vanadium(IV) ions in the compound. The temperature dependent magnetic susceptibility data showed the presence of a ferromagnetic coupling between the two V(IV) ions in the range 4–180K. [Copyright &y& Elsevier]

Single crystals of β-Li3VF6 (I) and Na3VF6 (II) are obtained by hydrothermal reaction of stoichiometric amounts of NH4VO3, NH4HF2, LiCl (NaCl), and fumaric acid (pH 4-6, autoclave, 240 °C, 24 h) without the need for HF. [ABSTRACT FROM AUTHOR]

The title compound is hydrothermally prepared from a solution of Y(NO3)3, NiSO4, MnO2, and KOH (autoclave, 533 K, 3 d) and characterized by powder XRD, SEM, XPS, and electric and magnetic measurements. [ABSTRACT FROM AUTHOR]

The title compounds are hydrothermally synthesized from solutions of Fe(NO3)3, CrCl3, Ln(NO3)3 (Ln: La, Tb, Ho, Er, Yb, Lu and Y), and KOH as a mineralizer (autoclave, 240 °C, 5 d) and characterized by powder XRD, SEM, and magnetic measurements. [ABSTRACT FROM AUTHOR]