Tunable asymmetric magnetoimpedance effect in ferromagnetic NiFe/Cu/Co films

摘要

We investigate the magnetization dynamics through the magnetoimpedance effectin ferromagnetic NiFe/Cu/Co films. We observe that the magnetoimpedanceresponse is dependent on the thickness of the non-magnetic Cu spacer material,a fact associated to the kind of the magnetic interaction between theferromagnetic layers. Thus, we present an experimental study on asymmetricmagnetoimpedance in ferromagnetic films with biphase magnetic behavior andexplore the possibility of tuning the linear region of the magnetoimpedancecurves around zero magnetic field by varying the thickness of the non-magneticspacer material, and probe current frequency. We discuss the experimentalmagnetoimpedance results in terms of the different mechanisms governing themagnetization dynamics at distinct frequency ranges, quasi-static magneticproperties, thickness of the non-magnetic spacer material, and the kind of themagnetic interaction between the ferromagnetic layers. The results placeferromagnetic films with biphase magnetic behavior exhibiting asymmetricmagnetoimpedance effect as a very attractive candidate for application as probeelement in the development of auto-biased linear magnetic field sensors.