Pervasive artifacts revealed from magnetometry measurements of rare earth-transition metal thin films

A class of artifacts manifesting as soft magnetic components are revealed from magnetometry measurements of rare earth-transition metal (TbFe) thin films prepared by magnetron sputtering. They are not inherent to TbFe, but are a direct result of the manner in which the substrates are mounted prior to sample fabrication, with a material deposited at the substrate sides giving rise to a significant magnetic moment. The authors find the same artifacts to also be present in rare earth-free [Co/Pt] multilayers. Trying to supress the appearance of this type of artifact has an influence on the coercivity and, in some cases, on the shape of the reversal curves. Care needs to be taken during fabrication to ensure reliable and reproducible samples so that sensitive magnetic parameters, such as coercivity and compensation points, can be extracted accurately and that data are not misinterpreted for even more complex systems. This type of artifact is not limited to samples prepared by sputtering but can extend to other conventional thin-film deposition methods.