The cuprate high temperature superconductors develop spontaneous charge density wave (CDW) order below a temperature $T_{\rm CDW}$ and over a wide range of hole doping ($p$). An outstanding challenge in the field is to understand whether this modulated phase is related to the more exhaustively studied pseudogap and superconducting phases. To address this issue, it is important to extract the...
In geometrically frustrated magnetism, the very nature of the ground state of Tb2Ti2O7, has remained a long standing conundrum. In this pyrochlore material, no conventional spin-ice or long-range magnetic order is stabilized, even at very low temperatures. Quantum fluctuations are suspected of being at the origin of such an exotic quantum phase, yet so far has lacked conclusive evidence. Using...
Sub-THz Raman response and critical dynamics in BaTiO3 (talk)
Marc D. Fontana1,2*, Ninel Kokanyan1,2, and Thomas H. Kauffmann1,2
1Université de Lorraine, CentraleSupélec, LMOPS, F-57000 Metz, France
2Laboratoire Matériaux Optiques, Photonique et Systèmes, CentraleSupélec, Université Paris-Saclay, 57070, Metz, France
marc.fontana@univ-lorraine.fr
BaTiO3 (BTO) is considered as a textbook...
This work reports the deposition of single phase Bi2ZnTiO6 thin films onto Pt/Si-based substrates using rf-sputtering method and the respective structural, morphological, optical and local ferroelectric characterization. The thin film grows in the polycrystalline form with tetragonal P4mm symmetry identified by X-ray diffraction. The lack of spatial inversion centre was confirmed by the second...
Ni$_{2}$MnGa is a multiferroic ferromagnetic shape memory alloy in which a large spontaneous deformation up to 12% has been observed after application of an external magnetic field [1]. The key to material functionalities is the ferroelastic microstructure of martensite with deep hierarchical twinning up to nanoscale [2]. However, the microscopic origin of the martensitic transformation...
High quality GdMnO3 thin films were deposited on SrTiO3 (001)-oriented substrates by RF magnetron sputtering. The structure, microstructure and polar properties were investigated in detail. The films grown up to a 35 nm thickness exhibit an epitaxial non-relaxed tetragonal symmetry, where the basal lattice parameters are imposed by the cubic symmetry of the substrate, contrarily to the...
Multiferroics, such as orthorhombic rare-earth manganites, where both magnetic and ferroelectric orders coexist and are coupled to one another, have attracted great interest. The simultaneity of magnetic and ferroelectric phases gives rise to important effects associated with the cross correlation between order parameters and external fields. A remarkable consequence is that the elementary...
