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Ren X.,Southwest Institute of Applied Magnetics | Xu G.,Southwest University of Science and Technology
Journal of Magnetism and Magnetic Materials | Year: 2014

NiCoZn-ferrites doped with La3+ ions, Ni0.35Co 0.15Zn0.5LaxFe2O4(x=0, 0.02, 0.04, 0.06), were prepared by sol-gel method. The effect of the La 3+ ions doping on the microstructure, complex permeability, permittivity and microwave absorption of the samples was investigated. The results show that all samples exhibited a well defined spinel phase when x≤0.04 with the sintering temperature of 1000 C. With the increase of the substitution ratio of La3+ ions from 0 to 0.06, the lattice parameters increased gradually, which resulted in the change of the particle shape and size. The data of magnetism showed that the addition of La 3+ ions result in the decrease of saturation magnetization (M s) and coercivity (Hc). The La3+ ions doped in the ferrite not only improved complex permittivity, but also microwave absorbency. The minimum reflection loss of -34 dB was obtained for x=0.02 sample for thickness t=4 mm and its bandwidth under -10 dB reaches 5.5 GHz. © 2013 Elsevier B.V. Source


Zheng F.,Southwest Institute of Applied Magnetics | Wang W.,China Academy of Engineering Physics
Jinshu Rechuli/Heat Treatment of Metals | Year: 2013

Effects of annealing time on phase structure and electrochemical properties of rapidly quenched LaNi3 hydrogen storage alloy were studied. The results show that the phase of rapidly quenched LaNi3 alloy is composed of LaNi3, LaNi5, La2Ni7, and LaNi2.28 phase. Annealed at 750 °C, the phase of the alloy is mainly composed of LaNi3 and La2Ni7phase. When the annealing time is short (0 h and 1 h), there are a little of LaNi5 phase, while annealed for 3 h, LaNi5 phase is almost disappeared. With annealing time increasing, the maximum discharge capacity increases from 145.94 mAh/g (0 h) to 176.44 mAh/g (3 h). Source


Xu G.,Southwest University of Science and Technology | Zeng L.,Southwest University of Science and Technology | Liu G.,Southwest University of Science and Technology | Yu H.,Southwest University of Science and Technology | Chen J.,Southwest Institute of Applied Magnetics
Yadian Yu Shengguang/Piezoelectrics and Acoustooptics | Year: 2012

The Y 3Fe 5O 12 (YIG) and Y 1.05Bi 0.75 Ca 1.2Fe 4.4V 0.6O 12 (YBiCaVIG) ferrites doped with different ZnO-B 2O 3-SiO 2 (ZBS) glass contents has been prepared by the common ceramics method. The phase composition, microstructure and magnetic properties of the samples were investigated. It was found that ZBS glasscould effectively decrease the sintering temperature of YIG and YBiCaVIG ceramics. When the doping content of ZBS was w(ZBS) =10%, the sintering temperature of YIG and YBiCaVIG ceramics could be reduced to 1280°C and 950°C respectively. But the XRD patterns showed that a few SiO 2 and YFeO 3 (YIP) impurities were formed, meanwhile, the SEM showed that the samples have the grain size of about 2~4 μm and higher pores rate. After doping ZBS glass, the saturation magnetizations 4π Ms decreased while the ferromagnetic resonance line width ΔH increased. However, since the samples have bigger spin wave line width ΔH k and smaller grain size, they are suitable for large power YIG materials. Source


Dai B.,Southwest University of Science and Technology | Lei Y.,Southwest University of Science and Technology | Shao X.-P.,Southwest University of Science and Technology | Ni J.,Southwest Institute of Applied Magnetics
Gongneng Cailiao/Journal of Functional Materials | Year: 2010

CoFe/Pt-CrMn exchange biased system was prepared by magnetron sputtering. The Mn content dependence of the pinning field was systematically studied. Have got the good performance of L10 phase Pt-CrMn, that is the CoFe/Pt50(Cr88Mn12)50, in which the interfacial exchange energy is 0.22×10-7J/cm2 and the Blocking temperature is 480°C. Source


Dai B.,Southwest University of Science and Technology | Lei Y.,Southwest University of Science and Technology | Shao X.P.,Southwest University of Science and Technology | Ni J.,Southwest Institute of Applied Magnetics
Journal of Alloys and Compounds | Year: 2010

In order to enhance the exchange coupling between antiferromagnetic PtCr and ferromagnetic CoFe based films, we have intentionally inserted FeMn or Mn at the interface but also throughout the volume part of the PtCr layer. Most differently from those studies with nonmagnetic impurities, the FeMn or Mn additive can largely increase the pinning field. These investigations reveal that Mn is the superior additive for this system. Especially, the small Mn concentration at the interface significantly improves the pinning field even by a factor of 4 while does not degrade the super thermal stability of PtCr. The strong dependence of exchange bias on the insertion layer will be argued to have its origin in increasing the moments of interfacial antiferromagnetic spins, and consequently, contribute to improve the pinning field. © 2009 Elsevier B.V. All rights reserved. Source

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