Magnetization Reversal in Submicron Disks: Exchange Biased Vortices

Abstract

Submicron, circular, ferromagnetic-antiferromagnetic dots exhibit different magnetization reversal mechanisms depending on the direction of the magnetic applied field. Shifted, constricted hysteresis loops, typical for vortex formation, are observed for fields along the exchange bias direction. However, for fields applied close to perpendicular to the exchange bias direction, magnetization reversal occurs via coherent rotation. Magnetic force microscopy imaging together with micromagnetic simulations are used to further clarify the different magnetic switching behaviors.

Chirality control via double vortices in asymmetric Co dots

“…Magnetic vortices in sub-micron sized dots have gained considerable interests in recent years due to their unique reversal mechanisms, fascinating topological properties, and potential applications in information storage, [1][2][3][4][5][6] spin-torque oscillators, 7,8 magnetic memory and logic devices, 9 and targeted cancer-cell destruction strategies. 10 Vortices are one type of topological defects characterized by an in-plane magnetization with a clockwise (CW) or counter-clockwise (CCW) chirality and a central core with an out-of-plane magnetization (up or down polarity).…”

Determination of the Fe magnetic anisotropies and the CoO frozen spins in epitaxial CoO/Fe/Ag(001)

“…These models were soon replaced by more sophisticate models which are believed to better represent realistic experimental systems [8,9,10]. In experiment, most of the early measurements are on the FM layer hysteresis loops to study the pinning effect [11,12,13], training effect [14,15,16], and the finite size effect [17,18], etc. One important issue in these studies is on how the AFM/FM interfacial coupling determines the FM layer exchange bias and the magnetic anisotropies.…”

Enhanced exchange bias in IrMn/CoFe deposited on self-organized hexagonally patterned nanodots

“…1 More recently, extensive efforts have been devoted to the fabrication and investigation of exchange biased nanostructures from both fundamental and technological points of view. [2][3][4][5][6][7][8][9][10][11][12][13] The continued size reduction of spintronic devices and the explosive growth of magnetic recording areal density have triggered intense interest in exchange biased nanostructures. 14 From the basic point of view, nanomaterials usually exhibit unique properties due to the reduction of the lateral dimensions.…”