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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 4: Multiferroics (joint session KFM/MA)

KFM 4.6: Vortrag

Montag, 16. März 2020, 17:00–17:20, HSZ 105

B-site doping effects in multiferroic rare-earth hexagonal manganites — •Marcela Giraldo¹, Martin Lilienblum¹, Hasung Sim², Lea Forster¹, Je-Geun Park², Thomas Lottermoser¹, and Manfred Fiebig¹ — ¹ETH Zurich, Switzerland. — ²Seoul National University, Korea.

Chemical doping is an alternative to tailor the properties of complex oxides. A–site doping in hexagonal RMnO₃ with Ca or Zr leads to a conductivity enhancement at the domain walls while preserving the characteristic topological ferroelectric state of the system. Stronger effects on the magnetism in this multiferroic family are expected by doping at the B–site. This is due to the direct perturbation of the magnetic sublattices formed by Mn³⁺ moments. We investigate Al-doping (0-25%) at the B–site in h-YMnO₃. We use a combination of second-harmonic generation (SHG) and piezoresponse force microscopy to disclose the effects on antiferromagnetic and ferroelectric domain formation. The later ones, for example, reveal a size decrease with increasing degree of doping. Furthermore, a combination of SHG and X-ray diffraction (XRD) unveils a decreasing trend for magnetic/electric ordering temperatures as a function of doping. This is due to the chemical pressure induced by the distinct ionic sizes of Al and Mn and the progressive decomposition of the long-range order. By tracing the changes in the inherent properties of these ferroic systems, we aim to broaden the understanding for new routes in the manipulation of this important class of multiferroics.