Southwest Institute of Applied Magnetics

Mianyang, China

Southwest Institute of Applied Magnetics

Mianyang, China
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Liu Y.,Yibin Vocational and Technical College | Cheng Y.,Yibin Vocational and Technical College | Hu Y.,Yibin Vocational and Technical College | Liu G.,Yibin Vocational and Technical College | Ren X.,Southwest Institute of Applied Magnetics
Hangkong Cailiao Xuebao/Journal of Aeronautical Materials | Year: 2016

La3+ doped NiCoZn-ferrite particles were prepared by the sol-gel method, the influence of La3+ content on microstructure, electromagnetic parameters and microwave absorbing properties was studied. Phase structure and microscope image of the sample were investigated by X-ray diffraction and scanning electron microscopy, their static magnetic properties and electromagnetic parameters at 1-12 GHz were measured by a vibrating sample magnetometer and vector network analyzer respectively, and the reflection loss was calculated with different thicknesses (3 mm, 5 mm, 8 mm). The results show that doping appropriate amount of La3+ can enhance the microwave absorption of Ni0.35Co0.15Zn0.5Fe2O4-ferrite, and remove the absorbing band to high frequency. When the sample thickness of Ni0.35Co0.15Zn0.5La0.04Fe2O4 mixed with paraffin is 5 mm, the minimum reflection loss is -28. 4dB, bandwidth (RL≤-10 dB) is 3.7 GHz. © 2016, Chinese Journal of Aeronautics. All right reserved.


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).


Ren X.,Southwest Institute of Applied Magnetics | Cheng Y.,Yibin Vocational and Technical College
Journal of Magnetism and Magnetic Materials | Year: 2015

Composite absorbers made from carbonyl iron powder and BaTiO3 were prepared by blending technique with the matrix of epoxy resin. The structure and microtopography of the carbonyl iron and BaTiO3 particles were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microstructure and electromagnetic properties of the as-prepared composites were investigated by SEM and vector network analyzer (VNA). The effect of the mass ratio of BaTiO3/carbonyl iron on the electromagnetic properties of the composites is investigated. The bandwidth with an absorption loss exceeding 30 dB is obtained in the whole measured frequency range for all composites, and an optimal reflection loss drop below 1.5 dB with 24 wt% BaTiO3. It is found that the carbonyl iron/BaTiO3 composite absorber can be a promising candidate as a matched load for the isolator. © 2015 Elsevier B.V. All rights reserved.


Lu L.,Colorado State University | Young J.,Colorado State University | Wu M.,Colorado State University | Mathieu C.,Seagate Technology | And 3 more authors.
Applied Physics Letters | Year: 2012

Tuning of the magnetization relaxation in Fe 65Co 35 thin films via seed layers was demonstrated. Through the use of different types of seed layers, one can tune substantially both the magnitude and frequency dependence of the relaxation rate η of the film. This tuning relies on the change of the film grain properties with the seed layer and the correlation between grain properties and two-magnon scattering processes. In spite of a significant change of η with the seed layer, the film static magnetic properties remain relatively constant. © 2012 American Institute of Physics.


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.


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.


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.


Wang L.,Southwest University of Science and Technology | Yu H.,Southwest University of Science and Technology | Ren X.,Southwest Institute of Applied Magnetics | Xu G.,Southwest University of Science and Technology
Journal of Alloys and Compounds | Year: 2014

For turning the magnetic resonance frequency and bandwidth of the reflection loss, different amounts of manganese (Mn) were incorporated into the BaCoTiFe10O19 for the substitution of cobalt (Co), then the BaMnxCo1-xTiFe10O19 was obtained via the solid-state reaction method. Subsequently, the effect of the doping Mn2+ on microwave absorption performances was detailedly studied in a frequency range from 2 to 18 GHz. The crystal volume expanded with increasing Mn2+ substitution as confirmed by X-ray diffraction results. No significant morphology change could be found in the scanning electron microscope images when Co2+ was partially substituted by Mn2+, but the coercivity and remanent magnetization raised as Mn 2+ increased. The complex permittivity and permeability were collected by the vector net-analyzer and the absorbing properties were calculated according to transmission theory. The absorption peak shifted to higher frequencies with the substitution. The maximum loss value of -30.5 dB at 13.4 GHz was observed for the x = 0.6 sample. Based on the magnetic and microwave measurements, BaMnxCo1-xTiFe 10O19 may be a good candidate for electromagnetic compatibility and other practical applications at high frequencies. © 2013 Elsevier Ltd. All rights reserved.


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.


Li S.,Southwest University of Science and Technology | Xiong K.,Southwest University of Science and Technology | Meng P.,Southwest University of Science and Technology | Ren X.,Southwest Institute of Applied Magnetics | Xu G.,Southwest University of Science and Technology
Journal of Materials Science: Materials in Electronics | Year: 2015

Copper(II)–titanium(IV)-doped barium ferrite (Ba(CuTi)xFe12−2xO19, x = 0, 0.5, 0.75, 1, 1.25) were prepared by the sol–gel method. The X-ray diffraction patterns of Ba(CuTi)xFe12−2xO19 proved that M-type barium hexagonal ferrite was formed. From the field emission scanning electron microscopy images, hexagon shaped grains could be obviously observed in Ba(CuTi)xFe12−2xO19 when x = 0.5, but its morphology tended to be irregular when x ≥ 0.75. In addition, the inductively coupled plasma atomic emission spectrometry test revealed that the doping limit of x was 0.75. Based on the electromagnetic parameters measured by the vector net-analyzer in the frequency of 2–18 GHz, the maximum reflection loss value of −37 dB at 16.7 GHz was observed for Ba(CuTi)xFe12−2xO19 (x = 0.75) with a matching thickness of 1.6 mm. Therefore, Ba(CuTi)xFe12−2xO19 may be a good candidate as the microwave absorbing material for the applications in the field of high frequency. © 2015, Springer Science+Business Media New York.

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