Antiferromagnetic materials can beat conventional ferromagnets in spintronics due to insensitivity to perturbations, up to THz operation, etc. We have grown micron-sized crystalline NiCoO films and determined their spin axes.

 Antiferromagnetic materials have gained attention due to their possible applications in spintronics owing to their advantageous properties: they are magnetically ordered, but neighboring magnetic moments point in opposite directions resulting in a zero net magnetization. Antiferromagnets thus produce no stray field and are almost insensitive to external magnetic field perturbations. Also, they present high frequency dynamics (in the THz regime) and exhibit considerable spin–orbit and magneto-transport effects However, in order to fully exploit their many potential applications, antiferromagnetic materials in thin film or nanostructured form are required. In this work, we present a spatially resolved X-ray magnetic linear dichroism (XMLD) study of high quality micron-sized mixed nickel-cobalt oxide (NCO) crystals. NixCo1−xO was prepared in-situ by high-temperature oxygen-assisted molecular beam epitaxy on a Ru(0001) single crystal substrate. To check the effect of incorporating Ni into the cobalt oxide films, three different compositions were prepared. Element-specific XMLD measurements reveal strong antiferromagnetic contrast at room temperature and magnetic domains up to one micron in size, reflecting the high structural quality of the NCO islands. By means of vectorial magnetometry, the antiferromagnetic spin axis orientation of the domains was determined with nanometer spatial resolution and found to depend on the stoichiometry of the prepared crystals. Mandziak, J. de la Figuera, A. Quesada, A. Berja, C. Granados-Miralles, J.E. Prieto, L. Aballe, M. Foerster, M.A. Niño, P. Nita, “Effect of Ni substitution on the antiferromagnetic domains of cobalt oxide”, Ultramicroscopy 253, 113795 (2023). DOI: 10.1016/j.ultramic.2023.113795. https://doi.org/10.1016/j.ultramic.2023.113795.