GMAG Dissertation Award Talk: Zero-moment Half-Metallic Ferrimagnetic Semiconductors

Low- and zero-moment half-metallic ferrimagnetic semiconductors [1,2] have been proposed for advanced applications, such as nonvolatile RAM memory and quantum computing. These inverse-Heusler materials could be used to generate spin-polarized electron or hole currents without the associated harmful fringing magnetic fields. Such materials are expected to exhibit low to zero magnetic moment at room temperature, which makes them well-positioned for future spin-based devices. However, these compounds have been shown to suffer from disorder [3]. This work focuses on the synthesis of these compounds and the investigation of their structural, magnetic, and transport properties. Cr$_{2}$CoGa and Mn$_{3}$Al thin films were synthesized by molecular beam epitaxy, and V$_{3}$Al and Cr$_{2}$CoAl were synthesized via arc-melting. Rietveld analysis was used to determine the degree of ordering in the sublattices as a function of annealing. The atomic moments were measured by X-ray magnetic circular and linear dichroism confirmed antiferromagnetic alignment of sublattices and the desired near-zero moment in several compounds.\\[4pt] In collaboration with George E. Sterbinsky, Photon Sciences Directorate, Brookhaven National Laboratory; Dario Arena Photon Sciences Directorate, Brookhaven National Laboratory; Laura H. Lewis, Chemical Engineering, Northeastern University; and Don Heiman, Physics, Northeastern University. \\[4pt] [1] H. van Leuken, R.A. de Groot, Phys. Rev. Lett. 74, 1171 (1995).\\[0pt] [2] S. Skaftouros, K. \"{O}zdo\u{g}an, E. \c{S}a\c{s}\i o\u{g}lu and I. Galanakis, Phys. Rev. B 87, 024420 (2013).\\[0pt] [3] M.E. Jamer, B.A. Assaf, T. Devakul and D. Heiman, Appl. Phys. Lett. 103, 142403 (2013).