CMD30 FisMat2023 - Submission - View

Abstract title: Magnetism and magnetoelectricity of textured thin films and polycrystalline bulk α-Cr2O3
Submitting author: Igor Veremchuk
Affiliation: Helmholtz-Zentrum Dresden-Rossendorf
Affiliation Address: Bautzner Landstraße 400, 01328 Dresden Germany
Country: Germany
Other authors and affiliations: Pavlo Makushko (Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Dresden, 01328, Germany), Natascha Hedrich (Department of Physics, University of Basel, Basel, 4056, Switzerland), Yevhen Zabila (Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Dresden, 01328, Germany), Tobias Kosub (Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Dresden, 01328, Germany), Maciej Oskar Liedke (Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Radiation Physics, Dresden, 01328, Germany), Maik Butterling (Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Radiation Physics, Dresden, 01328, Germany), Ahmed G. Attallah (Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Radiation Physics, Dresden, 01328, Germany), Andreas Wagner (Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Radiation Physics, Dresden, 01328, Germany), Fabian Ganss (Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Dresden, 01328, Germany), Ulrich Burkhardt (Max-Planck-Institut für Chemische Physik fester Stoffe, 01187 Dresden, Germany), Oleksandr V. Pylypovskyi (Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Dresden, 01328, Germany), René Hübner (Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Dresden, 01328, Germany), Jürgen Fassbender (Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Dresden, 01328, Germany), Patrick Maletinsky (Department of Physics, University of Basel, Basel, 4056, Switzerland), Denys Makarov (Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Dresden, 01328, Germany)
Abstract
Magnetoelectric antiferromagnets like α-Cr2O3 are attractive for the realization of energy-efficient and high-speed spin−orbitronic-based memory devices controlled by electric fields [1-3]. In contrast to single crystals, the quality of Cr2O3 thin films and bulk polycrystalline samples is usually compromised by the presence of point defects and their agglomerations at grain boundaries, putting into question their application potential. We experimentally investigated the defect nanostructure of magneton-sputtered 250-nm-thick Cr2O3 thin films prepared under different conditions on single crystals of Al2O3 (0001) and correlate it with the integral and local magnetic properties of the samples [4]. Also, we fabricated of polycrystalline bulk α-Cr2O3 sample in conditions far out of equilibrium relying on spark plasma sintering (SPS) allows high quality material with a density close to that of a single crystal [5]. The sintered sample possesses a preferential [0001] texture at the surface [5]. We evaluated the type and relative concentration of defects by positron annihilation spectroscopy (PAS). The Cr2O3 samples are characterized by the presence of complex defects at grain boundaries. The antiferromagnetic state of the sample and linear magnetoelectric effect are accessed all electrically relying on the spin Hall magnetoresistance effect in the Pt electrode interfaced with Cr2O3 [6]. The magnetotransport characterization reveals that the samples possesses the magnetic phase transition temperature of about 308 K. The antiferromagnetic domain patterns consist of small domains with size equals the grain size, which is formed due to the granular structure of the samples. Furthermore, the presence of larger defects like grain boundaries has a strong influence on the pinning of magnetic domain walls in studied samples. [1] X. He, Y. Wang, N. Wu, A. N. Caruso, E. Vescovo, K. D. Belashchenko, P. A. Dowben, C. Binek, Nature Mater., 9, 579 (2010).[2] T. Kosub, M. Kopte, R. Hühne, P. Appel, B. Shields, P. Maletinsky, R. Hübner, M. O. Liedke, J. Fassbender, O. G. Schmidt, D. Makarov, Nature Commun., 8, 13985 (2017).[3] N. Hedrich, K. Wagner, O. V. Pylypovskyi, B. J. Shields, T. Kosub, D. D. Sheka, D. Makarov, P. Maletinsky, Nature Phys., 17, 574 (2021). [4] I. Veremchuk, M. O. Liedke, P. Makushko, T. Kosub, N. Hedrich, O. V. Pylypovskyi, F. Ganss, M. Butterling, R. Hübner, E. Hirschmann, A. G. Attallah, A. Wagner, K. Wagner, B. Shields, P. Maletinsky, J. Fassbender, D. Makarov, Small, 18, 2201228 (2022).[5] I. Veremchuk, P. Makushko, N. Hedrich, Y. Zabila, T. Kosub, M. O. Liedke, M. Butterling, A. G. Attallah, A. Wagner, U. Burkhardt, O. V. Pylypovskyi, R. Hübner, J. Fassbender, P. Maletinsky, and D. Makarov, ACS Appl. Electron. Mater., 4, 2943 (2022).[6] R. Schlitz, T. Kosub, A. Thomas, S. Fabretti, K. Nielsch, D. Makarov, S. T. B. Goennenwein, Appl. Phys. Lett., 112, 132401 (2018).