非晶Fe89.7P10.3合金纳米线阵列的磁性研究

利用电化学沉积方法在阳极氧化铝模板中制备了Fe_89.7P_10.3非晶 合金纳 米线阵列.利用x射线衍射仪、透射电子显微镜、振动样品磁强计和穆斯堡尔谱仪研究了样品的结构和磁性,发现纳米线阵列是非晶结构，且拥有垂直磁各向异性和高的矫顽力，H_c =304×10⁴A/m.纳米线内部的平均超精细场和平均同质异能移分别为2 15×10⁶ A/m和007 mm/s；而纳米线末端的平均超精细场（233×10⁶ A/m ）大于内 部的值，平均同质异能移（004 mm/s）小于内部的值.另外，纳米线内部Fe原子磁矩与线轴的夹角约为16°，而在纳米线末端Fe原子磁矩与线轴的夹角约为28°.这些结果表明，由于形状各 向异性，在纳米线中实现了无序非晶合金磁矩的有序排列. 关键词： 非晶合金 纳米线阵列 垂直磁各向异性 穆斯堡尔谱     

Substrate Dependence of Properties of Sputtered ITO Films

High-quality indium-tin-oxide (ITO) films are deposited on p-type Czochralski silicon and 7059 Coming glass by direct-current magnetron sputtering at various temperatures. The structural, electrical and optical properties of the ITO films are investigated as functions of the substrate temperature. A comparison between the characteristics of the ITO films on silicon and Coming glass is presented. The results show that for the ITO film on silicon,the nucleation begins from room temperature; the resistivity reaches a maximum value at 75℃; the reflectivity increases with increasing temperature; when temperature is above 125℃, the ITO grows in a three-dimensional manner and forms a granular structure. However, for the ITO film on glass, it is still in an amorphous state at 75℃. Moreover, both the resistivity and the reflectivity decrease with increasing temperature. Above 125℃, the ITO grows in a two-dimensional manner and forms a domain structure.     

段化(A/B)m复合纳米线阵列的矫顽力机理

基于球链模型的对称扇形转动机理,考虑了段间的界面交换耦合作用,对利用电化学沉积方法制备的段化复合磁性纳米线六角阵列的磁滞回线进行了系统的研究,提出了矫顽力随复合段数m的变化规律.指出在这种段化复合纳米线阵列中,段间的交换耦合作用对磁化反转起着重要的影响.     

非晶Fe89.7 P10.3合金纳米线阵列的磁性研究

利用电化学沉积方法在阳极氧化铝模板中制备了Fe89.7P10.3非晶合金纳米线阵列.利用x射线衍射仪、透射电子显微镜、振动样品磁强计和穆斯堡尔谱仪研究了样品的结构和磁性,发现纳米线阵列是非晶结构,且拥有垂直磁各向异性和高的矫顽力,Hc=3.04×104A/m.纳米线内部的平均超精细场和平均同质异能移分别为2.15×106 A/m和0.07 mm/s;而纳米线末端的平均超精细场(2.33×106A/m)大于内部的值,平均同质异能移(0.04mm/s)小于内部的值.另外,纳米线内部Fe原子磁矩与线轴的夹角约为16°,而在纳米线末端Fe原子磁矩与线轴的夹角约为28°.这些结果表明,由于形状各向异性,在纳米线中实现了无序非晶合金磁矩的有序排列.     

Effects of notches on the order of flux-closure state formation in bi-rings by micromagnetic simulation

The effects of the number and the location of notches on the formation of flux-closure states in bi-rings with fields applied in the x direction (i.e., along the short axis direction of bi-rings) and y direction (i.e., along the long axis direction of bi-rings) are investigated using micromagnetic simulation. For the bi-rings with one notch and the bi-rings with two notches symmetric about y axis, the order of flux-closure state formation in each ring can be controlled. But the flux-closure state forms simultaneously in each ring for the bi-rings with two notches symmetric about x axis. For the bi-rings with two notches that are symmetric neither about x axis nor about y axis, only one ring can form a flux-closure state in the y-direction field and no flux-closure state can be found in rings in the x-direction field. Therefore, logic states can be defined by controlling the order of flux-closure state formation, which can be utilized in future logic devices.     

段化(A/B)m复合纳米线阵列的矫顽力机理

基于球链模型的对称扇形转动机理，考虑了段间的界面交换耦合作用，对利用电化学沉积方法制备的段化复合磁性纳米线六角阵列的磁滞回线进行了系统的研究，提出了矫顽力随复合段数m的变化规律.指出在这种段化复合纳米线阵列中，段间的交换耦合作用对磁化反转起着重要的影响. 关键词： 球链模型 复合纳米线 矫顽力 交换耦合     

Magnetic and Distribution of Magnetic Moments in Amorphous Fe89.7P10.3 Alloy Nanowire Arrays

Binary amorphous Fe89.7P10.3 alloy nanowire arrays in been fabricated in an anodic aluminium oxide template diameter of about 40nm and length of about 3μm have by electrodeposition. Magnetic properties of the samples are investigated by mean of vibrating sample magnetometer, transmission Mossbauer spectroscopy and conversion electron Mossbauer spectroscopy at room temperature. It is found that the nanowire arrays have obvious perpendicular magnetic anisotropy, and are ferromagnetic at room temperature, with its Mossbauer spectra consisting of six broad lines. The average angles between the Fe and 28° at the end of the amorphous Fe89.7P10.3 alloy magnetic moment and the wire axis are about 14°inside nanowire arrays, respectively. The magnetic behaviour is decided by the shape anisotropy and the dipolar interaction between wires. In addition, the magnetic moments distribution is theoretically demonstrated by using the symmetric fanning mechanism of the spheres chain model.     

Tuning of magnetic properties of aluminium-doped strontium hexaferrite powders

M-type Al-doped strontium ferrite powders(Sr Alx Fe_(2n-x) O_(19), n = 5.9) with nominal Al content of x = 0–2.0 are prepared by traditional ceramic technology. The phase identification of the powders, performed using x-ray diffraction,shows the presence of purity hexaferrite structure and absence of any secondary phase. The lattice parameters decrease with increasing x. The average grain size of the powders is about 300 nm–400 nm at Al~(3+)ion content x = 0–2.0. The roomtemperature hysteresis loops of the powders, measured by using vibrating sample magnetometer, show that the specific saturation magnetization(σ_s) value continuously decreases while the coercivity(Hc) value increases with increasing x, and Hc reaches to 9759 Oe(1 Oe = 79.5775 A/m) at x = 2.0. According to the law of approach saturation, Hc value increases with increasing Al~(3+)ion content, which is attributed to the saturation magnetization(Ms) decreasing more rapidly than the magnetic anisotropy constant(K_1) obtained by numerical fitting of the hysteresis loops. The distribution of Al~(3+)ions in the hexaferrite structure of Sr Alx Fe_(2n-x) O_(19) is investigated by using 57 Co Mssbauer spectroscopy. The effect of Al~(3+)doping on static magnetic properties contributes to the improvement of magnetic anisotropy field.