Search Results
Structure-property relationship of Co 2 MnSi thin films in response to He + -irradiation
2019, Hammerath, Franziska, Bali, Rantej, Hübner, René, Brandt, Mira R. D., Rodan, Steven, Potzger, Kay, Böttger, Roman, Sakuraba, Yuya, Wurmehl, Sabine
We investigated the structure-property relationship of Co2MnSi Heusler thin films upon the irradiation with He+ ions. The variation of the crystal structure with increasing ion fluence has been probed using nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM), and associated with the corresponding changes of the magnetic behavior. A decrease of both the structural order and the moment in saturation is observed. Specifically, we detect a direct transition from a highly L21-ordered to a fully A2-disordered structure type and quantify the evolution of the A2 structural contribution as a function of ion fluence. Complementary TEM analysis reveals a spatially-resolved distribution of the L21 and A2 phases showing that the A2 disorder starts at the upper part of the films. The structural degradation in turn leads to a decreasing magnetic moment in saturation in response to the increasing fluence.
Magnetic patterning of Co/Ni layered systems by plasma oxidation
2022, Anastaziak, Błażej, Andrzejewska, Weronika, Schmidt, Marek, Matczak, Michał, Soldatov, Ivan, Schäfer, Rudolf, Lewandowski, Mikołaj, Stobiecki, Feliks, Janzen, Christian, Ehresmann, Arno, Kuświk, Piotr
We studied the structural, chemical, and magnetic properties of Ti/Au/Co/Ni layered systems subjected to plasma oxidation. The process results in the formation of NiO at the expense of metallic Ni, as clearly evidenced by X-ray photoelectron spectroscopy, while not affecting the surface roughness and grain size of the Co/Ni bilayers. Since the decrease of the thickness of the Ni layer and the formation of NiO increase the perpendicular magnetic anisotropy, oxidation may be locally applied for magnetic patterning. Using this approach, we created 2D heterostructures characterized by different combinations of magnetic properties in areas modified by plasma oxidation and in the regions protected from oxidation. As plasma oxidation is an easy to use, low cost, and commonly utilized technique in industrial applications, it may constitute an improvement over other magnetic patterning methods.