Lecture Kathrin Doerr
|06 januari 2012||FWN-Building 5114.0004, Nijenborgh 4, 9747 AG, Groningen|
|Speaker:||Prof. Dr. Kathrin Doerr|
|Affiliation:||Institute for Physics, MLU Halle-Wittenberg|
|Title:||Strain control of ferroic properties in oxide films|
|Date:||Fri Jan 6, 2012|
|Telephone:||+313 50 363 4565|
The electronic properties of many correlated oxides showing magnetic or ferroelectric ordering are sensitive to elastic deformations of the crystal lattice. Therefore, predefined epitaxial strain states in such films bear the promise of efficiently controlling the ferroic properties. This includes the type of ferroic ordering, the polarization, the domain pattern and the switching dynamics.
I will address the approach of using monocrystalline piezoelectric substrates of Pb(Mg1/3Nb2/3)0.72Ti0.28O3(001) (PMN-PT) for reversible measurements of strain-dependent properties of epitaxially grown oxide films. After an introduction to the piezoelectric substrates, an example of a strain-driven magnetic phase transition in La0.8Sr0.2CoO3 films will be discussed. In the second part of the talk, experimental results on the strain-dependent ferroelectric switching of epitaxial PbZr1-xTixO3 films in reversibly controlled strain states will be presented. The switching time is found to be strongly strain-dependent in a way that is related to the strain-dependent polarization at high fields, but completely different at low fields. Thus, the strain dependence of ferroelectric switching reflects the different types of domain dynamics in the creep and the depinning / flow regime, promising a new access for characterizing and understanding the microscopic mechanism of ferroelectric switching.
|Laatst gewijzigd:||22 oktober 2012 14:31|