Barkhausen Jump Amorphous Ribbon Sensor by Means of Inducing Herical Anisotropy

利用非晶材料磁性能的显著可控性，通过引入由局部诱导的径向各向异性引起的畴壁钉钉，成功地制备了巴克豪森跳变传感器元件。巴克豪森跳变传感器元件能在绕组中产生尖锐脉冲电压，可应用于可靠的旋转编码传感器和方向传感器，无需电源。研究结果表明：(1)在退火过程中，在畴壁存在的区域内退火容易引起异质各向异性。该区域作为反畴的成核位点和畴壁的钉住中心，具有可重入性。(2)即使在较短的退火时间内引入的钉住力也相当大，使得带端反向畴形核并突然生长，参与了通量跳变。因此，脉冲电压（-do/dt）的抖动很大。为了改善这种情况，需要精确控制钉墙力。(3)非晶材料的壁宽可达2mu m，并随着诱导的各向异性增大，使壁内各向异性能量增加，与交换能达到平衡。

Depending on the remarkable controlability of magnetic properties in amorphous materials, an effort was made successfully to fabricate the Barkhausen jump sensor elements by means of introducing the domain wall pinning caused by the locally induced herical anisotropy. The Barkhausen jump sensor element can generate the sharp pulse voltage in windings, then can be applied to reliable rotary encorder sensor and directional sensor without power supply. The research results are summarized as follows,(1) The herical anisotropy can be easily induced by annealing into the region where the domain wall exists during annealing. This region works as nucleation sites of reverse domain and pinning centers of domain walls and the re-entrant properties can be available.(2) The pinning force introduced even in short annealing time is fairly large, so that the reverse domain nucleates at the ribbon ends and grows abruptly to participates in the flux jump. Consequently, the jitter of pulse voltage (-do/dt) is large. To improve that precise control of wall pinning force is needed.(3) The wall width of amorphous materials is as wide as 2mu m, and increases with the induced herical anisotropy to increase the anisotropy energy in the wall which makes balance with the exchange energy.