We measured saturated hysteresis loops of a MuMETAL ring using a computerized, high-resolution apparatus by both extrapolated continuous recording and automatic ballistic methods. The recording time per loop varied from 17.7 to 141.6 s. The loops obtained for short recording times were significantly wider than the loop obtained by the ballistic method. By extrapolating the magnetic field of different loops at the same flux density values linearly to zero flux density rate, the resultant dc loop had coercivity in agreement with its ballistic value. The results are quantitatively analyzed and discussed on the basis of eddy current models. The intolerably large variation and bias in the measured coercivity stated in a current ASTM standard may be resolved by this technique.

中文翻译：

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通过连续记录和自动弹道方法测量的 MuMETAL 环的直流磁滞回线

我们使用计算机化的高分辨率设备通过外推连续记录和自动弹道方法测量了 MuMETAL 环的饱和磁滞回线。每个循环的录音时间从 17.7 秒到 141.6 秒不等。短记录时间获得的环路明显比弹道法获得的环路更宽。通过将相同磁通密度值下不同回路的磁场线性外推到零磁通密度率，所得直流回路的矫顽力与其弹道值一致。在涡流模型的基础上对结果进行了定量分析和讨论。当前 ASTM 标准中规定的所测量矫顽力的不可容忍的大变化和偏差可以通过这种技术解决。