0000000000648272
AUTHOR
Andreas Herklotz
Strain-induced improvement of retention loss in PbZr0.2Ti0.8O3 films
The retention behavior of nanoscale domains in PbZr0.2Ti0.8O3 thin films is investigated by in-situ controlling the epitaxial strain arising from a piezoelectric substrate. The retention behavior in our sample shows strong polarity-dependence: Upward-poled domains exhibit excellent stability, whereas downward-poled domains reveal a stretched exponential decay. Reversible release of in-plane compressive strain strongly reduced the retention loss, reflected in an enhancement of the relaxation time by up to one order of magnitude. We tentatively attribute the observed behavior to a strain dependence of the built-in field at the interface to the La0.7Sr0.3MnO3 bottom electrode, with a possible …
Strain dependence of antiferromagnetic interface coupling in La0.7Sr0.3MnO3/SrRuO3 superlattices
We have investigated the magnetic response of La0.7Sr0.3MnO3/SrRuO3 superlattices to biaxial in-plane strain applied in-situ. Superlattices grown on piezoelectric substrates of 0.72PbMg1/3Nb2/3O3-0.28PbTiO3(001) (PMN-PT) show strong antiferromagnetic coupling of the two ferromagnetic components. The coupling field of mu0HAF = 2.8 T is found to decrease by deltaHAF/delta epsilon ~ -520 mT %-1 under reversible biaxial strain mu0HAF at 80 K in a [La0.7Sr0.3MnO3(22)/SrRuO3(55)]15 superlattice. This reveals a significant strain effect on interfacial coupling. The applied in-plane compression enhances the ferromagnetic order in the manganite layers which are under as-grown tensile strain. It is t…
Thermal generation of spin current in epitaxial CoFe2O4 thin films
The longitudinal spin Seebeck effect (LSSE) has been investigated in high-quality epitaxial CoFe2O4 (CFO) thin films. The thermally excited spin currents in the CFO films are electrically detected in adjacent Pt layers due to the inverse spin Hall effect (ISHE). The LSSE signal exhibits a linear increase with increasing temperature gradient, yielding a LSSE coefficient of ~100 nV/K at room temperature. The temperature dependence of the LSSE is investigated from room temperature down to 30 K, showing a significant reduction at low temperatures, revealing that the total amount of thermally generated magnons decreases. Furthermore, we demonstrate that the spin Seebeck effect is an effective to…