Temperature Dependent Magnetic Structures in Fe/Gd Films

Chiral magnetic phases are of significant interest due to their potential low energy, nonvolatile applications in spintronic devices. The proposed system, Fe/Gd multilayers, hosts magnetic, labyrinth / stripe domain and skyrmion chiral phases, and has been characterized by many techniques, including small angle neutron diffraction (SANS). In Fe/Gd multilayers, the stability of the chiral phases is a result of competing dipolar fields and exchange energy, producing an equal population of chiral spin textures with opposite helicity. By introducing Pt/ Ir heavy metals (HMs) into the structure, an additional energy from the interfacial Dzyaloshinkii-Moriya Interaction (DMI) can be introduced, leading to a preferential chirality in the spin textures. Here, we propose using polarized SANS to explore the net chirality through the volume of Fe/Gd multilayers with HMs in labyrinth domain states, which is expected to lead to intensity asymmetry in the resulting Bragg peaks. Preliminary Lorentz microscopy results provide evidence of this preferred chirality and that at temperatures below 180 K, more complex chiral phases exist. Additionally, exploration of the magnetic field (H) - temperature (T) phase space is proposed, which will be compared to Fe/Gd with no HMs. The process of annihilating domains is expected to show a strong dependence on the net chirality of the domain walls, and H-T phase space analyswill help build an understanding of how the DMI contributes to magnetic reversal.