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Efects of Molybdenum Concentration and Valence State on the Structural and Magnetic Properties of BaFe_(11.6)Mo_xZn_(0.4-x)O_(19) Hexaferrites

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Acta Metallurgica Sinica(English Letters) 2013年第5期26卷 509-516页

作者： G.H.Dushaq S.H.Mahmood I.Bsoul H.K.Juwhari B.Lahlouh M.A.AlDamen Physics Department The University of Jordan Physics Department Al al-Bayt University Chemistry Department The University of Jordan

Barium hexaferrites BaFe11.6Mox Zn0.4-x O19（x=0.1,0.2,0.4）were prepared by precipitation of the precursors using wet chemical mixture method and then sintering the dried powders at 1100℃.The properties of the prepared samples were investigated using X-ray difraction（XRD）,scanning electron microscopy（SEM）,vibrating sample magnetometer,and Mssbauer *** patterns revealed that all prepared samples had BaFe12O19hexaferrite structure as a majority *** images demonstated that the samples consisted mainly of hexagonal platelet-like grains with diameters ranging from 100 to 500 nm.Mssbauer spectra revealed that Zn2＋ions occupy 4f1 sites leading to the splitting of the 12k *** Mo6＋ions occupy 2b sites while Mo4＋ prefer 4f1 and 12k *** the sample with x=0.4,Mo6＋and Mo4＋ ions were found to have preference for 2b and 12k sites,respectively,and to induce the development of Fe2＋ions in the hexaferrite,leading to noticeable changes in the magnetic properties of the *** observed magnetic properties were found to be consistent with the preferential site occupation of metal ions,and the hyperfine fields derived from Mssbauer spectra of these samples.

关键词： Coercivity Barium Hexaferrites Mossbauer spectroscopy magneticproperties Hyperfine Interactions

Electronic transport and magnetic performance of Ni-Nb-Zr metallic glasses

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Rare Metals 2017年第11期36卷 894-898页

作者： Hai-Bin Wang Qing Wang Chong-Lin Chen Chuang Dong School of Materials Science and Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China School of Materials Science and Engineering Dalian University of Technology Dalian 116024 China Department of Physics and Astronomy University of Texas at San Antonio San Antonio TX 78249 USA

The electronic transport and magnetic perfor- mances of Ni-Nb-Zr metallic glasses under low temperature were investigated. X-ray diffraction （XRD） analysis indicates that the Ni-Nb-Zr ribbons prepared by induction melting and melt spinning method have single amorphous phase. The electrical transport property results of these metallic glass alloys indicate that the Ni-Nb-Zr metallic glasses have negative resistivity temperature coefficients （RTC） and low- temperature drift. The negative RTC and corresponding pos- sible values of Fermi energy of Ni-Nb-Zr metallic glasses are interpreted by the extended Ziman-Faber diffraction theory. The magnetic measurements indicate that the magnetic in- tensities of the Ni-Nb-Zr metallic glasses are related to Ni content and atomic sizes while the low temperature has few influences on the magnetic properties.

关键词： Metallic glass Electrical resistance magneticproperties

Effect of Sm-doping on the morphology and magnetic properties of radio frequency magnetron sputtered Ni-Mn-Ga films

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International Journal of Minerals,Metallurgy and Materials 2012年第6期19卷 555-560页

作者： Feng-hua Chen Min-gang Zhang Yue-sheng Chai Chang-wei Gong College of Materials Science and Engineering Taiyuan University of Science and Technology Talyuan 030024 China

Ni55.5Mn21Ga23.5 and Ni54Mn22Ga23Sml films were prepared by radio frequency （RF） magnetron sputtering. The effect of Sm do- pant on the morphologic and magnetic properties of Ni55.5Mn21Ga23.5 films was investigated. Sm doping can refine the particle size of the films from 100 to 60 nm, and further grain growth is not occurs even after annealing at 1073 K for 3.6 ks. Compared to Ni55.5Mn21Ga23.5 films, Sm-doped Ni54Mn22Ga23Sml films are easier to be magnetized and have a lower martensitic transformation temperature. In addition, the Curie temperature can also be adjusted, decreasing from 350 to 325 K after Sm doping. Martensitic transformation is not observed in the Sm-free films, which is close to the Curie temperature in the Sm-doped films, giving rise to the overlap of the structural and magnetic transi- tion temperatures.

关键词： magnetic films samarium doping magnetron sputtering martensitic transformation magnetic transition temperature magneticproperties rare earths

Effects of Heating Processing on Microstructure and Magnetic Properties of Mn-Zn Ferrites Prepared via Chemical Co-precipitation

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Journal of Wuhan University of Technology(Materials Science) 2015年第4期30卷 684-688页

作者：陈世杰 XIA Jingbing 代建清 School of Materials Science and Engineering Kunming University of Science and Technology

The fine powders of Mn-Zn ferrites with uniform size were prepared via chemical co- precipitation method. X-ray diffraction analysis （XRD）, scanning electron microscopy （SEM）, vibrating sample magnetometer （VSM）, frequency dependence of permeability and metallographical microscope were used to investigate the crystal structure, surface topography and magnetic properties of the powders and the sintering samples. The experimental results demonstrate that the precursor powders have formed a pure phase cubic spinel MnxZn1-xfe2O4 while in the reactor and show definite magnetism, which can solve the difficult issue in washing process effectively. When calcined beneath 450 ℃, the powders have intact crystal form and the crystallite size is less than 20 nm. Comparison tests of sintering temperatures show that 1 300 ℃ is the ideal sintering temperature for Mn-Zn ferrites prepared by using the chemical co-precipitation.

关键词： Mn-Zn ferrites chemical co-precipitation method surface morphology magneticproperties