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Liu L.,Hebei Normal University | Liu L.,Key Laboratory of Advanced Films of Hebei Province | Qi L.,Hebei Normal University | Han R.,Hebei Normal University | And 4 more authors.
Journal of Alloys and Compounds | Year: 2017

Co[sbnd]Cu dendrites were synthesized by pulse direct current electrodeposition (DC-PED) on polycrystalline Au substrate from a Co and Cu-sulphamate-based solution in a three-electrode system. Scanning electron microscopy images showed that the Co[sbnd]Cu dendrites consist of a long central backbone with secondary branches, which were composed of many neighbouring cubic-like nanoparticles. Tuning the pulse time was believed to be the key for the formation of a dendritic nanostructure. The X-ray diffraction (XRD) patterns indicated that the dendrite was composed of a solid solution of face-centered cubic Co[sbnd]Cu with preferred orientation of {111} planes and a face-centered cubic Co phase. The energy dispersive spectrometry (EDS) demonstrated that Co and Cu element composition distributed uniformly in the dendrite. Our results demonstrate that the co-deposition of Co and Cu ions is possible during the pulse electrodeposition process and which was dominated by the mechanism of thermodynamics and kinetics perspectives. Magnetic measurements showed that the Co[sbnd]Cu dendritic films exhibit ferromagnetism and easy-axis direction of the magnetization is perpendicular to the film plane. © 2016 Elsevier B.V.


Xu Q.,Hebei University of Technology | Xu Q.,Key Laboratory of Advanced Films of Hebei Province | Ye W.-J.,Hebei University of Technology | Feng S.-Z.,Hebei Normal University | And 3 more authors.
Dyes and Pigments | Year: 2014

A simple method of fabricating Co-containing anodic aluminum oxide films for multifunctional anti-counterfeit technology is reported. The films display highly saturated colors after being synthesized by an ac electrodeposition method. Tunable color in the films is obtained by adjusting anodization time, and can be adjusted across the entire visible range. Magnetic measurements indicate that such colored composite films show excellent magnetic properties. The resulted short (310 nm in length) and wide (50 nm in diameter) Co nanowires present only hexagonal close-packed phase, with the coercivity and squareness ratio as high as 1.2 × 105 A/m and 0.803, respectively. The magnetization reversal mechanism is in good agreement with coherent rotation model. The color and magnetic properties remain the same over a wide temperature range. The Co-containing anodic aluminum oxide films with structural color and perpendicular magnetic recording properties have friability-resistant feature and could be used in many areas including decoration, display and multifunctional anti-counterfeiting applications. © 2014 Elsevier Ltd. All rights reserved.


Zhang J.-J.,Hebei Normal University | Zhang J.-J.,Hebei Medical University | Zhang J.-J.,Key Laboratory of Advanced Films of Hebei Province | Hou X.,Hebei Normal University | And 5 more authors.
AIP Advances | Year: 2013

A simple method to fabricate porous anodic alumina films embedded with Fe is reported. The films exhibit vivid structural colors and magnetic properties after being synthesized by an ac electrodeposition method. The optical properties of the samples can be effectively tuned by varying the oxidation time of aluminum. The coercivity mechanism of the Fe nanowires in our case is consistent with fanning reversal mode. PAA@Fe films can be used in many areas including decoration, display and multifunctional anti-counterfeiting applications. © 2013 © 2013 Author(s).


Xu Q.,Hebei Normal University | Xu Q.,Key Laboratory of Advanced Films of Hebei Province | Sun H.-Y.,Hebei Normal University | Sun H.-Y.,Key Laboratory of Advanced Films of Hebei Province | And 6 more authors.
Applied Surface Science | Year: 2011

Porous anodic alumina thin films with iridescent colors were fabricated electrochemically in phosphoric acid electrolyte. Compared to the color saturation of alumina films fabricated in oxalic acid electrolyte, the saturation obtained using phosphoric acid was enhanced dramatically. The mechanisms behind this observation are discussed, and the microstructure and optical characteristics of the films are characterized. Multicolor patterns were obtained by an organics-assisted process for which details are given. © 2011 Elsevier B.V. All rights reserved.


Zhang X.,Hebei Normal University | Zhang X.,Key Laboratory of Advanced Films of Hebei Province | Zhang H.,Hebei Normal University | Zhang H.,Hebei University of Science and Technology | And 9 more authors.
Journal of Magnetism and Magnetic Materials | Year: 2013

FeNi alloy nanowires and nanotubes have been fabricated in the pores of the anodized aluminum oxide (AAO) templates by direct current electrodeposition with different potentials. The crystal structure and micrograph of FeNi alloy nanowires and nanotubes were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, and the content was confirmed by energy dispersive spectrometry. The results indicate that there is a critical potential in the formation of nanowires and nanotubes. FeNi alloy nanowires and nanotubes both present the (111) preferred orientation, and the content of Fe is reduced with the decrease of electrodeposition potentials. The magnetic behaviors of FeNi alloy nanowires and nanotubes with different ratios are investigated. The coercivity of FeNi alloy nanowires and nanotubes exhibits disparate behavior, which may attribute to their grain size and distinctive structure. CrownCopyright © 2012 Published by Elsevier B.V. All rights reserved.


Sun H.-Y.,Hebei Normal University | Sun H.-Y.,Key Laboratory of Advanced Films of Hebei Province | Zhang H.-M.,Hebei Normal University | Zhang H.-M.,Key Laboratory of Advanced Films of Hebei Province | And 9 more authors.
Journal of Materials Chemistry C | Year: 2013

Room-temperature ferromagnetism has been observed in Porous Anodic Aluminum (PAA) thin films, with an out-of-plane saturation magnetization of 60 emu cm-3. The significant out-of-plane saturation magnetization is associated with the porous structure of the film. As there were no magnetic impurities present, the origin of the ferromagnetism is most likely due to exchange interactions between localized electron spin moments resulting from oxygen vacancies in the films. A similar hysteretic behavior is observed in porous thin films of nonmagnetic TiO2 and ZnO. This suggests that ferromagnetism may be a universal characteristic of porous thin films of nonmagnetic metal oxides. Our present results suggest a promising direction for research in spintronic devices. © 2013 The Royal Society of Chemistry.


Hou X.,Hebei Normal University | Hou X.,Key Laboratory of Advanced Films of Hebei Province | Sun H.,Hebei Normal University | Sun H.,Key Laboratory of Advanced Films of Hebei Province | And 6 more authors.
Journal of Magnetism and Magnetic Materials | Year: 2015

Porous Cu2O films have been fabricated on porous anodic alumina substrates using DC-reactive magnetron sputtering with pure Cu targets, and unexpectedly large room temperature ferromagnetism has been observed in the films. The maximum saturation magnetic moment along the out-of-plane direction was as high as 94 emu/cm3. Photoluminescence spectra show that the ferromagnetism originates with oxygen vacancies. The ferromagnetism could be adjusted by changing the concentration of oxygen vacancies through annealing in an oxygen atmosphere. These observations suggest that the origin of the ferromagnetism is due to coupling between oxygen vacancies with local magnetic moments in the porous Cu2O films, which can occur either directly through exchange interactions between oxygen vacancies, or through the mediation of conduction electrons. Such a ferromagnet without the presence of any ferromagnetic dopant may find applications in spintronic devices. © 2015 Elsevier B.V. All rights reserved.


Gu J.,Hebei Normal University | Gu J.,Key Laboratory of Advanced Films of Hebei Province | Yang S.,Hebei Normal University | Yang W.,Hebei Normal University | And 4 more authors.
Journal of Magnetism and Magnetic Materials | Year: 2014

Multiferroic composite thin films with composition (1-x)BiFeO 3-xNiFe2O4 (x=0.00, 0.10, 0.15, 0.20, 0.25, and 0.30) were prepared by chemical solution deposition(CSD). The results show that with increasing x, the average size of the crystal grains of BiFeO3 diminishes gradually, and the leakage current density in composite thin films decreases while the remnant polarizations increases. The calculated results for the ferromagnetic contribution of the NiFe2O4 indicated that BiFeO3 also contributed magnetic moment to the composite films. On comparing the grain sizes and magnetic measurement results of the composite thin films with x=0.20 and 0.25, we found that the decreasing crystal grain size of the BiFeO3 was responsible for ferromagnetism and that the enhanced magnetoelectric coupling effect in composite thin films was also an important factor. © 2013 Elsevier B.V.


Wu T.,Hebei Normal University | Wu T.,Key Laboratory of Advanced Films of Hebei Province | Sun H.,Hebei Normal University | Sun H.,Key Laboratory of Advanced Films of Hebei Province | And 8 more authors.
Microporous and Mesoporous Materials | Year: 2014

Remarkable room-temperature ferromagnetism was found in porous TiO 2 thin films deposited on porous anodic alumina substrates using DC-reactive magnetron sputtering. A physical property measurement system measurement indicates that the out-of-plane saturation magnetization is about 126 emu/cm3. The magnetization depends on special porous structure and decreases rapidly after air-annealing. These suggest that the origin of ferromagnetism may be due to exchange interactions between singly ionized oxygen vacancies directly (F+-F+), or by mediation of conduction electrons (F+-conduction electrons-F+) in the porous TiO2 thin films. The results reveal that it is a promising candidate for spintronic devices. © 2014 Published by Elsevier Inc.


Zhang H.-M.,Hebei Normal University | Zhang H.-M.,Hebei University of Science and Technology | Zhang H.-M.,Key Laboratory of Advanced Films of Hebei Province | Zhang X.-L.,Hebei Normal University | And 7 more authors.
Journal of the Electrochemical Society | Year: 2013

A possible growth mechanism for template-based electrodeposition metal nanotubes was presented.We proposed that the formation of nanotube was a result of kinetics controlling the deposition process, and was related to the crystal structure. According to the mechanism, various nanotubes, such as Zn, Co, Cu, Ni, ZnNi, and CoNi, were fabricated with aluminum oxide templates using a DC electrodeposition method. The deposit morphology dependence of potential was discussed. We further elaborated the feasibility of the mechanism from crystal growth perspective as well as kinetics and thermodynamics perspectives. This work will benefit further understanding the growth process of electrodeposited nanotubes, and provide important experimental data for crystal growth theory. © 2012 The Electrochemical Society.

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