Synthesis and characterization of novel magnetic Heusler semiconductors for device and materials applications

Michelle Jamer (Northeastern University)

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 little to zero magnetic moment at room temperature, which makes them well-positioned for future spin-based devices. However, the predicted compounds have been shown to suffer from disorder.[3,4] This work focuses on the growth of low-moment inverse-Heusler compounds and the investigation of their structural, magnetic, and transport properties. Cr₂CoGa and Mn₃Al thin films were synthesized by molecular beam epitaxy, and V₃Al and Cr₂CoAl were synthesized via arc-melting.[5,6] Annealing and X-ray diffraction studies were carried out in order to optimize the inverse-Heusler structure. 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 performed at the National Synchrotron Light Source and compared to magnetization results. These studies confirmed antiferromagnetic alignment of sublattices and the desired near-zero moment in several compounds.

[1] H. van Leuken, R.A. de Groot, Phys. Rev. Lett. 74, 1171 (1995).
[2] S. Skaftouros, K. Özdoǧan, E. Şaşioǧlu and I. Galanakis, Phys. Rev. B 87, 024420 (2013).
[3] M.E. Jamer, B.A. Assaf, T. Devakul and D. Heiman, Appl. Phys. Lett. 103, 142403 (2013).
[4] M.E. Jamer, B.A. Assaf, G.E. Sterbinsky, D. Arena, and D. Heiman, J. Appl. Phys. 116, 213914 (2014).
[5] M.E. Jamer, B.A. Assaf, G.E. Sterbinsky, D. Arena, L.H. Lewis, A.A. Saúl, G. Radtke, and D. Heiman, Phys. Rev. B 91, 094409 (2015).
[6] M.E. Jamer, L. G Marshall, G.E. Sterbinsky, L.H. Lewis, and D.Heiman, accept. to J. Magn. Magn. Mater. 06/15.

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