Magnetization State and Magnetic Structure of Wiegand Wire Evaluated by External Magnetic Field Measurement

Wiegand wires exhibit unique and fast magnetization reversal features, termed as large Barkhausen jumps, in externally applied alternating magnetic fields. However, the mechanisms and magnetization states yielding these large Barkhausen jumps are yet to be sufficiently elucidated. Thus, in this study, we analyzed the magnetization state and magnetic structure of a Wiegand wire by measuring the magnetic field of the wire. Moreover, we defined a four-layer magnetic structure model of the Wiegand wire and analyzed the magnetization states and processes of these layers in an applied alternating magnetic field. In addition, we determined the switching field of each layer and specified the magnetization states resulting in the large Barkhausen jump.

I. Introduction

Wiegand wires are widely known for their bistable magnetization states [1]. Owing to such magnetic structures, these wires exhibit fast magnetization reversal, which is termed a “large Barkhausen jump.” This unique feature of Wiegand wires generates a pulse voltage in the pickup coil wound around the wire. Therefore, Wiegand wires have recently been used in self-powered rotary encoders [2], energy harvesters [3], magnetic reference marks in positioning systems [4], and various other circuits and applications [5], [6], [7].