Ferromagnetic feature from Mn near room temperature in the fine particles of GdMn2Ge2 and TbMn2Ge2

The magnetization behaviors of GdMn2Ge2 and TbMn2Ge2 in the bulk and in the fine particles obtained by high-energy ball-milling are compared. Pronounced modificayions in the spontaneous, remnent and high-field magnetization in the fine particle form, attributable to Mn are observed. The results indicate that the antiferromagnetism of Mn sub-lattice known for the bulk form in the range 100-300 K gets weakened in favor of ferromagnetism in the fine particles. On the basis of this observation, we infer that there are other factors like size (and possibly defects) also play a role to decide the exact nature of magnetic ordering of Mn in this ternary family of compounds, contrasting the traditionally held view that the basal plane Mn-Mn distance is the crucial controlling parameter.Comment: Communicated for publication on 2nd January 201

Structure and conformation of 2,3,4-triphenyl-1-oxa-4-azabutadiene

WOS: 0000886826000152,3,4-triphenyl-1-oxa-4-azabutadine (C20H15NO) has been studied by X-ray analysis and AMI molecular orbital methods. It crystallises in the triclinic space group P-l with a = 9.414(3), b = 10.479(3), c = 8.385(2) Angstrom, alpha = 103.31(3)degrees beta = 97.10(3)degrees, gamma = 74.09(1)degrees, V = 772.5(4) Angstrom(3), Z = 2, D-c = 1.227 g cm(-3), and mu(MoK alpha) = 0.075 mm(-1) and F-000 = 300. The structure was solved by direct methods and refined to R = 0.043 for 2672 reflections [I > 2 sigma(1)]. The conformational analysis of the title compound were investigated by semi-empirical quantum mechanical AM1 calculations. The minimum conformation energies were calculated as a function of the three torsion angles theta(1)(O(1)C(7)C(8)N( 1)), theta(2)(C(8)N(1)C(IS)C(16)) and theta(3)(C(14)C(9)C(8)N(1)). The results are compared with the X-ray results. C=O and C=N groups are twisted about each other by 95.5(2)degrees. (C) 2000 Elsevier Science B.V. All rights reserved

Soft Magnetic Properties of HfxCo100-x Thin Films

Durak Yuzuak, Gizem/0000-0002-2358-8789WOS: 000415284200026HfxCo100-x thin films (in the atomic weight range of x = 30-36) were growth on Si (100) substrates by direct current (DC) magnetron sputtering method. Thin films produced with atomic compositions in this context depicted the amorphous structure. the films revealed soft magnetic properties and thus exhibited very low hysteresis along the hard-axis direction. Magnetic measurements indicated that Hf35Co65 thin film has the maximum saturation magnetization (1491 emu cm(-3)) at 300 K. Additionally, magnetization measurements show an increase in saturation magnetization value from 981 to 1491 emu cm(-3) when the value of x varies between 30 and 35. the influence of varying sputtering pressure and film composition on soft magnetic properties are investigated and discussed in the present paper.Ankara University BAPAnkara University [15L0443005]; Research Fund of the Recep Tayyip Erdogan University [BAP 2014.109.06.01, 2014.109.06.02]; BAP 2014.109.06.01 and 2014.109.06.02Supported by the Ankara University BAP under Grant 15L0443005, Research Fund of the Recep Tayyip Erdogan University (Project Numbers: BAP 2014.109.06.01 and 2014.109.06.02). G.D.Y. would like to thank TUBITAK - BIDEB 2211-C Program for Ph.D. Scholarship

Magnetic Features of Boron Doping on Hf2Co11 Thin Films

WOS: 000435577000015The effect of boron (B) doping on the structural and magnetic properties is studied systematically in the Hf2Co11 thin films. the modified crystal microstructure and annealing process enhanced the coercive field up to 1754 Oe. in order to obtain superior magnetic properties, the optimum doping ratios should be properly controlled attentively. To identify the structure, B-doped Hf2Co11 thin films were investigated by temperature-dependent X-ray diffraction analysis for the first time. the hard magnetic phase of Hf2Co11 B (x) thin films was formed to orthorhombic phase with some Co impurities and had a crystallization temperature around 823 K.Ankara University BAPAnkara University [15L0443005]; TUBITAK-BIDEB 2211-C ProgramThis study is supported by the Ankara University BAP under Grant 15L0443005. Gizem Durak Yuzuak would like to thank TUBITAK-BIDEB 2211-C Program for Ph.D. scholarship

Hf2Co11 thin films: Rare-earth-free permanent nanomagnets

Durak Yuzuak, Gizem/0000-0002-2358-8789WOS: 000397374500019Hf2Co11 thin films were deposited on single crystalline Si(100) substrates by using conventional direct current (DC) magnetron sputtering with a Hf2Co11 alloy target. All films were grown at room temperature with 120W sputtering power. in order to obtain the composition of the desired, the working pressure was changed from 0.66 to 1.05 Pa. the relationships between structural and magnetic properties in Hf-Co films were studied by using differential thermal analyzer, glancing incidence X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, atomic force microscopy, magnetic force microscopy and vibrating sample magnetometer. It revealed that the as-deposited films were amorphous at room temperature for all deposition pressures and showed soft ferromagnetic phase. in order to increase the coercive field associated with an advancing transition to hard phase, thin films were post-annealed from 773 K to 973 K. Post-annealing process led to a high remanence magnetization and improved the squareness of the demagnetization curve. Their saturation magnetization values varied from 515 to 1378 kA/m and also coercive field values varied from 52x10(-4) to 153x10(-3) Tat room temperature depending on post-annealing temperatures. Hf2Co11 soft ferromagnetic phase was modified by formation of post-annealing and was given rise to enhance permanent magnet properties (saturation magnetization, coercive field, energy product). the magnetic properties of thin films were found to be convenient for nanomagnet applications. (C) 2017 Elsevier B.V. All rights reserved.Ankara University Research FundsAnkara University [BAP 15L0443005]; TUBITAK 2211-C ProgramThis work was performed in the Magnetic Materials Research Laboratory in Ankara University - Functional Materials Research Laboratory in Recep Tayyip Erdogan University and supported by Ankara University Research Funds (grant number: BAP 15L0443005). G.D.Y. would like to thank to TUBITAK 2211-C Program for Ph.D. scholarship

Structures of four- and six-coordinate monomers of [N,N '-bis(5-chlorosalicylidene)-1,3-diaminopropane]nickel(II)

WOS: 000165618200004[N,N' -Bis(5-chlorosalicylidene) -1,3 -diaminopropane] nickel(II) [Ni(C17H14N2O2Cl2)] 1 and [N,N' -Bis(5-chlorosalicylidene)-1,3 -diaminopropane] nickel(II) dihydrate [Ni(C17H14N2O2Cl2).2(H2O)] 2 were synthesized, and their crystal structures were determined. Compound 1 is monoclinic, space group C2/c, a = 21.063(4), b = 8.151(1), c = 9.421(2) Angstrom, beta = 94.16(1)degrees, V = 1613.2(5) Angstrom (3), Z = 4 and D-c = 1.680 g cm(-3). Compound 1 contains a crystallographic twofold axis, and the whole molecule is not planar. The two Schiff base moieties, which in themselves are planar, are twisted with respect to one another. The least-squares planes through each half of the molecule are inclined at an angle of 29.1(1)degrees. The Ni atom is in a square-planar environment. The Ni-N and Ni-O distances are 1.958(2) and 1.910(2) Angstrom, respectively. Compound 2 is orthorhombic, space group Pnma, with a = 7.892(1), b = 23.396(2), c = 9.992(1) Angstrom, V = 1846.3(3) Angstrom (3), Z = 4 and D-c = 1.597 g cm(-3). Compound 2 has crystallographic mirror symmetry, and again, the whole molecule is not planar. The two planar Schiff base moieties inclined at an angle of 38.7(1)degrees. The Ni atom is in a distorted octahedral geometry and coordinated by the donor atoms of the ligand in the horizontal plane, and the coordination sphere is completed by O atoms of two water molecules