arXiv subjects

R. Desfeux

Publications and source records attributed to R. Desfeux.

4 recordsLinked to original sources

arXiv2009

Constrained ferroelectric domain orientation in (BiFeO3)m(SrTiO3)n superlattice

Ferroelectric domains were investigated using piezoresponse force microscopy in superlattices composed of multiferroic BiFeO3 and SrTiO3 layers. Compared to single BiFeO3 thin films, a reduction in the domains size and a suppression of the in-plane orientation of domains are observed in a superlattice of (BiFeO3)4(SrTiO3)8, suggesting a constrained ferroelectric domain orientation along the out-of-plane <001> direction. Such modification of domain size and orientation in BiFeO3-based heterostructures could play a vital role on engineering the domains and domain wall mediated functional properties necessary for device applications

cond-mat.mtrl-sci↗

arXiv2009

Probing of local ferroelectricity in BiFeO3 thin films and (BiFeO3)m(SrTiO3)m superlattices

Ferroelectric BiFeO3 thin films and artificial superlattices of (BiFeO3)m(SrTiO3)m (m~ 1 to 10 unit cells) were fabricated on (001)-oriented SrTiO3 substrates by pulsed laser ablation. The variation of leakage current and macroscopic polarization with periodicity was studied. Piezo force microscopy studies revealed the presence of large ferroelectric domains in the case of BiFeO3 thin films while a size reduction in ferroelectric domains was observed in the case of superlattice structures. The results show that the modification of ferroelectric domains through superlattice, could provide an additional control on engineering the domain wall mediated functional properties.

cond-mat.mtrl-sci↗

arXiv2001

Substrate-effect on the magnetic microstructure of La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ thin films studied by magnetic force microscopy

Colossal magnetoresistive (CMR) La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ (LSMO) thin films have been grown under tensile strains on (100)-SrTiO$_{3}$ substrates and compressive strains on (100)-LaAlO$_{3}$ and (110)-NdGaO$_{3}$ substrates by pulsed laser deposition. Using magnetic force microscopy (MFM), a "feather-like" magnetic pattern, characteristic of films with an in-plane magnetization, is observed for films deposited on both SrTiO$_{3}$ and NdGaO$_{3}$ while a "bubble" magnetic pattern, typical of films with an out-of plane magnetization, is recorded for LaAlO$_{3}$. We show that the shape of the magnetic pattern imaged by MFM is fully correlated to the easy direction of the magnetization in the film.

cond-mat.mtrl-sci↗

arXiv1997

Optical conductivity of CuO_2 infinite-layer films

The infrared conductivity of CaCuO_2, SrCuO_{2-y}, and Sr_{0.85}Nd_{0.15}CuO_2 infinite-layer films is obtained from reflectivity measurements by taking into account the substrate contribution. SrCuO_{2-y} and Sr_{0.85}Nd_{0.15}CuO_2 exhibit extra-phonon modes and structured bands in the midinfrared, not found in stoichiometric CaCuO_2. These features mirror those observed in the perovskitic cuprates, thus showing that the polaronic properties of high-T_c superconductors are intrinsic to the CuO_2 planes.

cond-mat.supr-con↗