Effects of yttrium on the formation and magnetic properties of bulk metallic glassy （Fe, Co）-B-Si-Nb alloys

The bulk metallic glassy (BMG) rods of [(Fe0.5Co0.5)0.72B0.192Si0.048Nb0.04]100-xYx (x=0-6) and [(FexCo1-x)0.72B0.192Si0.04]Nb0.04]96Y4 (x=0.5-0.8) were prepared by copper mold casting. The structure, thermal stability,and magnetic properties of the samples were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and vibrating sample magnetometer (VSM). Adding lat% to 6at% of yt-trium, the bulk glassy alloy rods of [(Fe0.5Co0.5)0.72B0.192Si0.048Nb0.04]100-xYx (x=0-6) with the diameter of 3 mm were not formed, and the sample with 4at% of yttrium showed less crystalline phase than others. When the Fe/Co atomic ratio was between 5:5 and 7:3, the bulk glassy alloy rods of [(Fe1-xCox)B0.192Si0.048Nb0.04]96Y4 (x=0.5-0.8) with the diameter of 2 mm were fabricated. In the (Fe, Co)-B-Si-Nb-Y BMGs, when the Fe content increased, the thermal stability, the supercooled liquid region, and the glass-forming ability (GFA) decreased, but the saturation magnetization (Ms) increased.     

中国的交变弱磁场磁感应强度标准

本文介绍了中国交变弱磁场磁感应强度标准的组成原理、装置各部分设备的主要指标、及标准装置各项误差的估计。比较装置传递交变磁感应强度量具的不确定度达０．０４７％。实现在１ｋＨｚ以下频率范围内复现１００ｎＴ～０．７ｍＴ交变磁感应强度的总不确定度（３σ）小于（０．１２％＋１０＾－８Ｔ／Ｂｎ），为统一我国交变弱磁感应强度的单位量值提供了技术手段和量值依据。     

磁场测量技术的发展及其应用

磁场测量技术的发展和应用有着悠久的历史,目前已经广泛应用于地球物理、空间技术、军事工程、工业、生物学、医学、考古学等许多领域.本文沿物理学原理和效应的脉络对目前比较常用的磁场测量方法进行介绍,并依据近年来的进步特征指出,高准确度、高稳定度、高分辨率、微小型化、数字化、智能化是磁场测量技术及仪器发展的必然方向.     

磁通门磁强计用于测量磁性材料内禀矫顽力的改进措施

用磁通门磁强计测量磁性材料内禀矫顽力(如图1所示),是将由两个磁通门探头(或霍尔探头)构成的两个差分磁通敏感探头放置在螺线管外面,而这两个探头和磁强计连接,被测试样放在螺线管中部,螺线管在反向电流磁场作用下使试样退磁,当磁化强度为零肘,磁强计的示值指示为零,从而测定该试样的矫顽力。但是这种磁强计的示值是否为零是