National Center for Quality Supervision and Testing of Magnetic Materials and Products

Hangzhou, China

National Center for Quality Supervision and Testing of Magnetic Materials and Products

Hangzhou, China
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Zhou H.,China Jiliang University | Wei G.,China Jiliang University | Li M.,China Jiliang University | Wang J.,China Jiliang University | And 5 more authors.
Journal of the Electrochemical Society | Year: 2013

This work concerns the Fe50Pt50/Fe2Pt 98 magnetic multilayers electrodeposited from ionic liquid system. Iron concentration in the Fe-Pt films was ranging from 1.65 at% to 76.45 at% when the deposition potentials were changed from -1.0 V to -2.2 V vs Ag/AgCl in electrodeposition system at 353 K. Fe50Pt50/Fe 2Pt98 multilayers were successfully electrodeposited from the ionic liquid system at 353 K by controlling the pulse electrodeposition potential. Current transients revealed that the nucleation of Fe 50Pt50 layer was a three-dimensional instantaneous nucleation growth controlled by diffusion. Fe50Pt50/ Fe2Pt98 multilayers of four-bilayer structure (FBS) were prepared with single-bath technique using pulse electrodeposition under potential control. The cross-sectional images of multilayers showed distinct layers with columnar structure. X-ray diffraction (XRD) pattern showed that the fct structure of Fe50Pt50/Fe2Pt98 multilayer had been obtained. Magnetic hysteresis loops showed that perpendicular coercivity values were increased from 153 Oe to 800 Oe with the increase of Fe50Pt50 layer thickness in FBS from 118 nm to 300 nm. FBS exhibited a magnetic anisotropic behavior. © 2013 The Electrochemical Society. All rights reserved.


Zhou H.R.,China Jiliang University | Wei G.Y.,China Jiliang University | Lou J.W.,China Jiliang University | Cao Y.,China Jiliang University | And 4 more authors.
Surface Engineering | Year: 2013

FePt magnetic multilayers were pulse electrodeposited from the mixture of ammonium hexachloroplatinate and iron dichloride in ionic liquids based on glycol (EG) and 1-ethyl-3-methylimidazolium chloride (EMIC). The chelate effect and electrochemical behaviour of the EMIC with the ions were determined by ultraviolet-visible spectra and cyclic voltammetry respectively. The iron atomic content in the FePt films ranged from 0.4 to 81.0 at-% when deposition potentials changed from 1.0 to 22.0 V(Ag/AgCl) in electrodeposition system with the EG (50 mL), ammonium hexachloroplatinate (25 mM L-1), iron dichloride (175 mM L-1) and EMIC (25 mM L-1) at 393 K. Fe50Pt50 thin films with smooth surface (50 at-% iron layer in FePt film) and the multilayer cross-section were obtained. Fct structural FePt multilayer was obtained based on X-ray diffraction pattern. Magnetic hysteresis loops showed that the multilayer possessed a magnetic anisotropic behaviour. © 2013 Institute of Materials, Minerals and Mining.


Wei G.,China Jiliang University | Zhou H.,China Jiliang University | Ge H.,China Jiliang University | Ge H.,National Center for Quality Supervision and Testing of Magnetic Materials and Products | Dettinger H.,ZEH Metallveredelungs GMBH
Surface Engineering | Year: 2016

This work concerns FePt nanowires electrodeposited from electrolyte of E1 [ammonium hexachloroplatinate (25 mM L-1), 1-ethyl-3-methylimidazolium chloride (25 mM L-1)], iron dichloride (315 mM L-1) and glycol (50 mL) at 393 K. FePt nanowires and films were electrodeposited by controlling the electrodeposited time under suitable potential in E1. FePt nanowires were prepared at different times of 600, 800 and 1000 s when deposition potential was 2.0 V versus Ag/AgCl. The SEM patterns proved that FePt nanowires were prepared at suitable deposition time (600-1000 s). The X-ray diffraction pattern indicated that the face centre tetragonal structure of FePt nanowires was obtained. Magnetic hysteresis loops showed that aggregation could decrease the coercivity, and some nanowires were larger than the mean diameter, which exhibited a comparatively large ferromagnetic behaviour. © 2016 Institute of Materials, Minerals and Mining.


Wei G.,China Jiliang University | Jin Y.,DMEGC Magnetic Ltd Company | Yu Y.,China Jiliang University | Ge H.,China Jiliang University | And 4 more authors.
Thin Solid Films | Year: 2010

CoPtWP magnetic thin films were prepared by electroless deposition. The influence of bath pH, deposition temperature and bath composition on the deposition speed, alloy content, microstructure, and magnetic properties of CoPtWP thin films were investigated. It was found that deposition speed increased gradually with the bath pH and deposition temperature. The cobalt content in the CoPtWP thin films varied from 77 at.% to 85 at.% by controlling the bath pH. The microstructure of CoPtWP thin films was dependent on bath pH and deposition temperature: two mixed structures, face centered cubic (fcc) and hexagonal close packed (hcp), were observed at low pH values and low deposition temperature. With the increase of pH values and deposition temperature, the intensity of fcc (111) peak suppressed gradually. The surface morphology was markedly influenced by bath pH, deposition temperature and bath composition. VSM and MFM measurements revealed that perpendicular coercivity had been increased with the bath pH. Unique hard magnetic properties of CoPtWP thin films with large perpendicular magnetic anisotropy were obtained at 90 °C and bath pH 13.0. © 2010 Elsevier B.V. All rights reserved.


Wei G.Y.,China Jiliang University | Lou J.W.,China Jiliang University | Ge H.L.,China Jiliang University | Ge H.L.,National Center for Quality Supervision and Testing of Magnetic Materials and Products | And 3 more authors.
Surface Engineering | Year: 2012

The influence of different complexing agents with hydroxycarboxylic acid group on the electrodeposited Co-W thin films has been investigated. Comparison between the polarization curves shows that the negative shift on the electrodeposition potential increased in the following order: no complexing agent, tartrate, malate, gluconate and citrate. The particular shapes of the j-t transients indicate that a nucleation and growth process was involved for the Co-W electrodeposition in the presence of complexing agents investigated. The reduced current transients follow the instantaneous nucleation model for all four complexing agents at the initial stages. Surface morphology, phase composition and magnetic properties were observed by means of field emission SEM, X-ray diffraction and vibrating sample magnetometer respectively. It has been found out that surface morphology and phase composition were markedly affected by the nature of the complexing agents. In the absence of complexing agents and in the presence of citrate, reflections of Co 7W 6, Co (1 0 0) and Co (0 0 2) appeared simultaneously. For the deposits obtained from solutions containing malate, there are two main peaks: Co 7W 6 and Co (0 0 2). In the case of tartrate, two peaks of Co are observed: Co (0 0 2) and Co (1 0 0). Reflections of Co (0 0 2) appeared for the deposits prepared from gluconate baths. Co-W magnetic thin films presented good soft magnetic properties (H c52 Oe, M s51403 emu cm -3) compared with pure cobalt thin films (1370 emu cm -3) when 0.3 mol L 21 citrate was used as complexing agent. © 2012 Institute of Materials, Minerals and Mining.

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