Perpendicular exchange bias of (Pt/Co)_n/FeMn multilayers

(Pt/Co)n/FeMn multilayers with perpendicular anisotropy (PA) were prepared by magnetron sputtering with Pt as the buffer layer and the capping layer. The dependence of perpendicular exchange bias (PEB), Hex, on the thickness of the FeMn antiferromagnet (AFM) layer is similar to that of in-plane exchange bias. The value of Hex for the (Pt/Co)3/FeMn multilayer reaches 22.3 kA/m. A thin Pt spacer was inserted between the Co/FeMn interface to enhance PEB. The PEB reaches the largest at 39.8 kA/m when the thickness of the Pt spacer is 0.4 nm.     

Perpendicular magnetic anisotropy of Co85Cr15／Pt multilayers

The CoCr/Pt bilayers and (CoCr/Pt)20 multilayers with Pt underlayer were prepared by DC magnetron sputtering. The ef- fects of prepared condition on perpendicular magnetic anisotropy were investigated. The results show that the thickness of Pt underlayer has a great effect on the microstructure and perpendicular magnetic anisotropy of CoCr/Pt bilayers and (CoCffPt)20 multilayers.When the thickness of Pt undedayer increases, Pt(lll) and CoCr(002) peaks of both CoCr/Pt bilayers and (CoCr/Pt)20 multilayers increase and the bilayer periodicity of the multilayers is improved. The effective magnetic anisotropy of (CoCrfPt)20 multilayers with Pt undedayer was much larger than that of CoCr/Pt bilayers. The (CoCr/Pt)20 multilayers has a stronger perpendicular magnetic anisotropy than that of CoCr/Pt bilayers. This is ascribed to the interface magnetic anisotropy of the multilayers.     

Perpendicular magnetic anisotropy of Co_(85)Cr_(50)/Pt multilayers

The CoCr/Pt bilayers and (CoCr/Pt)20 multilayers with Pt underlayer were prepared by DC magnetron sputtering. The effects of prepared condition on perpendicular magnetic anisotropy were investigated. The results show that the thickness of Pt under-layer has a great effect on the microstructure and perpendicular magnetic anisotropy of CoCr/Pt bilayers and (CoCr/Pt)20 multilayers. When the thickness of Pt underlayer increases, Pt(111) and CoCr(002) peaks of both CoCr/Pt bilayers and (CoCr/Pt)20 multilayers increase and the bilayer periodicity of the multilayers is improved. The effective magnetic anisotropy of (CoCr/Pt)20 multilayers with Pt underlayer was much larger than that of CoCr/Pt bilayers. The (CoCr/Pt)20 multilayers has a stronger perpendicular magnetic anisotropy than that of CoCr/Pt bilayers. This is ascribed to the interface magnetic anisotropy of the multilayers.     

快速热处理的[Fe/Pt]n薄膜的结构和磁性

采用直流磁控溅射方法在Si基片上制备[Fe/Pt]_n薄膜,利用X射线荧光光谱仪(XRF)、X射线衍射仪(XRD)和振动样品磁强计(VSM)分析薄膜的组分、结构和磁性。研究结果表明：[Fe/Pt]_n薄膜经过600 ℃快速热处理,得到了L1₀-FePt薄膜。对于[Fe (x nm)/Pt (0.5 nm)]_n薄膜,当Fe层厚度为0.7 nm时,薄膜的有序度最大,平行膜面和垂直膜面的矫顽力均最高;对于不同调制周期的[Fe/Pt]_n薄膜,有序度随调制周期先增大后减小,平行膜面的矫顽力均高于垂直膜面的矫顽力,当调制周期为2.4 nm时,薄膜平行膜面的矫顽力最大。     

Magnetic property and interlayer segregation in spin valve metal multilayers

The experimental results show that the exchange coupling field of NiFe/FeMn for Ta/ NiFe/FeMn/Ta multilayers is higher than that for the spin valve multilayers Ta/NiFe/Cu/NiFe/FeMn/ Ta. In order to find out the reason, the composition and chemical states at the surfaces of Ta( 12nm)/ NiFe(7nm), Ta( 12nm)/NiFe(7nm)/Cu(4nm) and Ta( 12nm)/NiFe(7nm)/Cu(3nm)/NiFe(5nm) were studied using the X-ray photoelectron spectroscopy (XPS). The results show that no elements from lower layers float out or segregate to the surface for the first and second samples. However, Cu atoms segregate to the surface of Ta(12nm)/NiFe(7nm)/Cu(3nm)/NiFe(5nm) multilayers, i.e. Cu atoms segregate to the NiFe/FeMn interface for Ta/NiFe/Cu/NiFe/FeMn/Ta multilayers. We believe that the presence of Cu atoms at the interface of NiFe/FeMn is one of the important factors causing the exchange coupling field of Ta/NiFe/FeMn/Ta multilayers to be higher than that of Ta/NiFe/Cu/NiFe/ FeMn/Ta multilayers.     

Supramolecular Sheet Co(Ⅱ) Complex Assembled by Hydrogen Bond

The title complex,[[Co(Py)2(H2O)2(NO3)2]]n(1)was synthesized by liquid/liquid diffusion method at room temperature.The complex crystallizes in monoclinic,space group P2(1)/C,with a=0.877 5(6)nm,b=1.171 5(8)nm,c=0.751 8(5)nm,V=0.739 3(9)nm3,C10H14CoN4O8,Mr=377.18,Dc=1.694 g/cm3,μ=1.210 mm-1,F(000)=386,Z=2,the final R=0.022 9 and wR=0.066 1 for 3 137 observed reflections(I>2σ(I)).In the structure of 1,the center atom of cobalt revealed a centrosymmetric,six-coordinate structure,with two Py ligands,two monoden...     

Structure and Mixed Electronic-ionic Conducting Properties of La0.6Sr0.4Co1-yFeyO3（y= 0-1.0） Ceramics Made by a Citrate Method

La0.6Sr0.4Co1-yFeyO3（y= 0-1.0） powders were synthesized by a citrate method, and the structure and mixed electronic-ionic conducting properties of the resulting ceramics were investigated. The synthesized La0.6Sr0.4Co1-yFeyO3 powders have a pure perovskite structure and consist of uniform and fine particles. A perovskite struciure with rhombohedral symmetry was certified for the La0.6Sr0.4Co1-yFeyO3 ceramics. The increase of Co/Fe ratio significantly promoted the grain growth and microstructural densification. The La0.6Sr0.4Co1-yFeyO3 compositions with relatively higher Co/Fe ratio exhibit superior mixed conducting properties. The electronic structure and microstructure of the ceramics are responsible for the variation of the mixed conducting properties with Co/Fe ratio.     

Preparation and Electrocatalytic Activity of Polyaniline-poly （Propylene Oxide） Modified by Pt Nanoparticles

The preparation and electrocatalytic activity of polyaniline-poly （ propylene oxide ） （ PAN-PPO ） modified by Pt particles （ Pt/ PAN-PPO ） were investigated. Pt/ PAN-PPO was characterized by scanning electron microscopy （SEM） and energy dispersive spectroscopy （ EDS ）. Pt particles on PAN-PPO were in the nanometer range, and dispersed in a three-dimensional distribution on the surface of PAN-PPO film. Compared with polyaniline and glassy carbon modified with Pt particles under the same conditions, Pt/PAN-PPO exhibited a high electrocatalytic activity for lysine oxidation.     

Giant magnetoresistance effect in Ni buffered Co/Cu/Co sandwich

The effects of Ni buffer layer on the giant magnetoresistance structure of Co/Cu/Co sandwich are investigated systematically in this paper. It is found that Ni buffer layer can induce the crystallization of the lower Ni/Co layer and produce small coercivity, thus enlarging the difference in the magnetic behavior between the two magnetic layers in the sandwich. Moreover, the use of the Ni buffer layer can also improve the interface flatness in the sandwich. All these factors enhance the sensitivity of the Ni buffered sandwich.     

Structure and Electrical Properties of （Na0.5Bi0.5）0.94Ba0.06TiO3 Ceramicwith0.5wt% of MnO

The structure and electrical properties of （Na0.5Bi0.5）0.94Ba0.06TiO3 ceramic doped with 0.5 wt% of MnO were investigated in comparison with those of （Na0.5Bi0.5）0.94Ba0.06TiO3 ceramic. It was ascertained that the MnO addition did not cause remarkable change in crystal structure and microstructure. The MnO addition mainly displayed a hard effect on the electrical properties, an increase of coercive field （E） and mechanical quality factor （Qm） together with a decrease of dielectric constant （εr） and piezoelectric constant （d33）. An enhancement of electromechanical coupling factor （kp） with the MnO addition was obtained too. An essential relation between the piezoelectric properties and ferroelectric nature of the ceramics was detected. It was found that the piezoelectric properties of the ceramics highly depended on the corporative contribution of remanent polarization （Pt） and coercive field.     

Perpendicular exchange bias of （Pt/Co）n/FeMn multilayers

(Pt/Co)n/FeMn multilayers with perpendicular anisotropy (PA) were prepared by magnetron sputtering with Pt as the buffer layer and the capping layer. The dependence of perpendicular exchange bias (PEB), Hex, on the thickness of the FeMn antiferromagnet (AFM) layer is similar to that of in-plane exchange bias. The value of Hex for the (Pt/Co)3/FeMn multilayer reaches 22.3 kA/m. A thin Pt spacer was inserted between the Co/FeMn interface to enhance PEB. The PEB reaches the largest at 39.8 kA/m when the thickness of the Pt spacer is 0.4 nm.     

Perpendicular magnetic anisotropy of Co85Cr15/Pt multilayers

The CoCr/Pt bilayers and (CoCr/Pt)20 multilayers with Pt underlayer were prepared by DC magnetron sputtering. The effects of prepared condition on perpendicular magnetic anisotropy were investigated. The results show that the thickness of Pt underlayer has a great effect on the microstructure and perpendicular magnetic anisotropy of CoCr/Pt bilayers and (CoCr/Pt)20 multilayers.When the thickness of Pt underlayer increases, Pt(111) and CoCr(002) peaks of both CoCr/Pt bilayers and (CoCr/Pt)20 multilayers increase and the bilayer periodicity of the multilayers is improved. The effective magnetic anisotropy of (CoCr/Pt)20 multilayers with Pt underlayer was much larger than that of CoCr/Pt bilayers. The (CoCr/Pt)20 multilayers has a stronger perpendicular magnetic anisotropy than that of CoCr/Pt bilayers. This is ascribed to the interface magnetic anisotropy of the multilayers.     

正极材料LiNi_（0.4）Mn_（0.4）Co_（0.2）O_2的制备和性能

采用草酸共沉淀法合成了锂离子正极材料LiNi0.4Mn0.4Co0.2O2。用XRD、SEM和充放电实验对合成产物的结构、形貌和电化学性能进行了表征;用DSC对合成产物在不同充电状态下的热稳定性进行了研究。结果表明,采用草酸共沉淀法合成的正极材料LiNi0.4Mn0.4Co0.2O2具有α-NaFeO2型层状结构,阳离子有序度高,粒度均匀适中,电化学性能良好,首次放电比容量达到158.7 mAh/g,30次循环后放电比容量还有144.8 mAh/g;过充电状态下具有良好的热稳定性。     

Fabrication and Magnetic Properties of Composite Ni_(0.5)Zn_(0.5)Fe_2O_4/Pb(Zr_(0.52)Ti_(0.48))O_3 Nanofibers by Electrospinning

One-dimensional and quasi-one-dimensional nanostructure materials are promising building blocks for electromagnetic devices and nanosystems.In this work,the composite Ni0.5Zn0.5Fe2O4(NZFO)/ Pb(Zr0.52Ti0.48)O3(PZT) nanofibers with average diameters about 65 nm are prepared by electrospinning from poly(vinyl pyrrolidone) (PVP) and metal salts.The precursor composite NZFO/PZT/PVP nanofibers and the subsequent calcined NZFO/PZT nanofibers are investigated by Fourier transform infrared spectroscopy (FT- IR) ,X-ray diffraction (XRD),scanning electron microscopy (SEM).The magnetic properties for nanofibers are measured by vibrating sample magnetometer(VSM).The NZFO/PZT nanofibers obtained at calcination temperature of 900 °C for 2 h consist of the ferromagnetic spinel NZFO and ferroelectric perovskite PZT phases,which are constructed from about 37 nm NZFO and 17 nm PZT grains.The saturation magnetization of these NZFO/PZT nanofibers increases with increasing calcination temperature and contents of NZFO in the composite.     

基于MCzHQZn的有机电致发光器件

通过结构为ITO/2T-NATA(20nm/NPBx(20nm)/MCzHQZn(30nm)/BCP(10nm)/Alq3(20nm)/LiF(0.5nm)/Al、ITO/2T-NATA(30nm/MCzHQZn(30nm)/BCP(10nm)/Alq3(30nm)/LiF(0.5nm)/Al和ITO/2T-NATA(20nm/MCzHQZn(30nm)/NPBx(16nm)/BCP(10nm)/Alq3(25nm)/LiF(0.5nm)/Al的3组有机电致发光器件(OLED),证明了MCzHQZn既具有空穴传输特性,又具有较好的发光特性。MCzHQZn在器件1中作发光层,器件最大亮度在电压16V时达到3692cd/m2,电压13V时的最大效率为0.90cd/A,发光的峰值波长为564nm;MCzHQZn在器件2中既作发光层又作空穴传输层,器件最大亮度在电压为13V时达到1929cd/m2,电压12V时的最大效率为0.57cd/A,发光的峰值波长也为564nm;MCzHQZn在器件3中作空穴传输层,由NPBx作发光层,器件最大亮度在电压为14V时达到3556cd/m2,电压9V时的最大效率为1.08cd/A,...     

固相反应制备Pt/C催化剂及其对甲醇的电催化氧化

运用固相反应方法制备得Pt质量分数为20％的Pt/C催化剂,并通过X射线衍射、透射电镜和电化学分析方法比较了制得的催化剂与E-TEK公司Pt／C催化剂、传统液相反应方法制得的Pt/C催化剂间的性能差别．结果表明：运用固相反应方法和传统液相化学反应方法制得的Pt/C催化剂中,Pt粒子的平均粒径分别为3．8nm和8．5nm;并且,利用固相反应方法制得的Pt/C催化剂拥有较高的电化学活性面积,其对甲醇的电催化氧化活性和稳定性与E-TEK公司的Pt／C催化剂相当．远远优于传统的液相反应方法制得的Pt／C催化剂．