Berlin 2015 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 4: Focused Session on Ferroic Domain Walls I (DF with MA)

DF 4.3: Vortrag

Montag, 16. März 2015, 15:50–16:10, EB 107

Domain wall motion in proper and improper ferroelastic materials — •Wilfried Schranz — University of Vienna, Faculty of Physics, Boltzmanngasse 5, Vienna, Austria

Many proper and improper ferroelastic materials display (at low measurement frequncies) a huge elastic softening below Tc. This giant elastic softening is caused by domain wall motion and can be supressed with uniaxial stress. Here we review our results on frequency and temperature dependent elastic measurements of SrTiO₃ [1], KMnF₃ and KMn_1−xCa_xF₃ [2], PbZrO₃, NH₄HC₂O₄·1/2H₂O [3] and BaFe₂As₂ [4] and put them into context with data from literature. We also present a model [5] based on Landau-Ginzburg theory to describe superelastic softening observed in some of the perovskite systems (improper ferroelastic) as well as in iron based superconductors (pseudo-proper ferroelastic) and show, how the theory can be extended to describe the effects of domain miniaturization (e.g. near morphotropic phase boundaries) on the macroscopic porperties of materials.

Supported by the Austrian FWF (P23982-N20).
A.V. Kityk, W. Schranz, P.Sondergeld, D. Havlik, E.K.H. Salje and J.F. Scott, Phys. Rev. B 61, 946 (2000) [2] W. Schranz, P. Sondergeld, A.V. Kityk and E.K.H. Salje, Phys. Rev. B 80, 094110 (2009) [3] W. Schranz, H. Kabelka, A. Sarras and M. Burock, Appl. Phys. Lett. 101, 141913 (2012) [4] A.E. Böhmer, P.Burger, F. Hardy, T. Wolf, T. P. Schweiss, R. Fromknecht, M. Reinecker, W. Schranz and C. Meingast, Phys. Rev. Lett. 112, 047001 (2014) [5] W. Schranz, Phys. Rev. B 83, 094120 (2011)