We investigated the magnetic structure in epitaxial Fe films on GaAs(001) by taking advantage of planar Hall effect combining with static and dynamic magnetization measurements. The depth dependence of the magnetic structure was evidenced as a result of competition between in-plane interfacial uniaxial and bulk cubic magnetic anisotropies. The competing results exposed by these techniques allow us to image a spiral magnetic structure nearby the interface of the Fe/GaAs(001) system. This work provides an insight for electrical and magnetic properties in an ultrathin hybrid ferromagnet/non-magnet system.
