Strain mediated magnetoelectric coupling induced in (x) Bi0.5Na0.5TiO3-(1-x) MgFe2O4 composites

Particulate composites of ferroelectric and ferrite phases having general formula (x) Bi0.5Na0.5TiO3-(1-x) MgFe2O4 (x= 0, 0.5, 0.6, 0.7, 0.8 and 1.0), equivalently denoted as (x) BNT-(1-x) MgFO were synthesized by solid state reaction method. From X-ray diffraction analysis, the structural transformation from tetragonal to rhombohedral corresponding to BNT phase was observed in composites with x= 0.5 to x= 0.8. Shifting of (012) BNT peak towards left (x= 0.5, 0.8) and right side (x= 0.6, 0.7) observed due to occupation of Bi3+ ions at interstitial and substitutional sites into host MgFO lattice respectively. BNT produced strain in MgFO lattice. Scanning electron micrographs show closely packed microstructure with grain size variations from 0.62 to 2.90 aem. The value of magnetoelectric (ME) coupling coefficient increases from 2.42 (x= 0.5) to 4.79 (x= 0.8) mV/cm. Oe due to strain produced in MgFO and BNT lattices

The TeraFERMI Electro-Optic Sampling Set-Up for Fluence-Dependent Spectroscopic Measurements

TeraFERMI is the THz beamline at the FERMI free-electron-laser facility in Trieste (Italy). It uses superradiant Coherent Transition Radiation emission to produce THz pulses of 10 to 100 μ J intensity over a spectral range which can extend up to 12 THz. TeraFERMI can be used to perform non-linear, fluence-dependent THz spectroscopy and THz-pump/IR-probe measurements. We describe in this paper the optical set-up based on electro-optic-sampling, which is presently in use in our facility and discuss the properties of a representative THz electric field profile measured from our source. The measured electric field profile can be understood as the superimposed emission from two electron bunches of different length, as predicted by electron beam dynamics simulations

Direct-write x-ray nanopatterning: a proof of concept josephson device on Bi2Sr2CaCu2O8+δ superconducting oxide

We describe the first use of a novel photoresist-free X-ray nanopatterning technique to fabricate an electronic device. We have produced a proof-of-concept device consisting of a few Josephson junctions by irradiating microcrystals of the Bi2Sr2CaCu2O8+δ (Bi-2212) superconducting oxide with a 17.6 keV synchrotron nanobeam. Fully functional devices have been obtained by locally turning the material into a nonsuperconducting state by means of hard X-ray exposure. Nano-XRD patterns reveal that the crystallinity is substantially preserved in the irradiated areas that there is no evidence of macroscopic crystal disruption. Indications are that O ions have been removed from the crystals, which could make this technique interesting also for other oxide materials. Direct-write X-ray nanopatterning represents a promising fabrication method exploiting material/material rather than vacuum/material interfaces, with the potential for nanometric resolution, improved mechanical stability, enhanced depth of patterning, and absence of chemical contamination with respect to traditional lithographic techniques

Direct-Write X-ray Nanopatterning: A Proof of Concept Josephson Device on Bi2Sr2CaCu2O8+δ Superconducting Oxide

We describe the first use of a novel photoresist- free X-ray nanopatterning technique to fabricate an electronic device. We have produced a proof-of-concept device consisting of a few Josephson junctions by irradiating microcrystals of the Bi2Sr2CaCu2O8+δ (Bi-2212) superconducting oxide with a 17.6 keV synchrotron nanobeam. Fully functional devices have been obtained by locally turning the material into a nonsuperconducting state by means of hard X-ray exposure. Nano-XRD patterns reveal that the crystallinity is substantially preserved in the irradiated areas that there is no evidence of macroscopic crystal disruption. Indications are that O ions have been removed from the crystals, which could make this technique interesting also for other oxide materials. Direct-write X-ray nanopatterning represents a promising fabrication method exploiting material/material rather than vacuum/material interfaces, with the potential for nanometric resolution, improved mechanical stability, enhanced depth of patterning, and absence of chemical contamination with respect to traditional lithographic techniques

Nonlinear TeraHertz transmission by liquid water at 1 THz

The solvation properties of liquid water originate from the transient network of hydrogen-bonded molecules. In order to probe the coupling between the different modes of this network, nonlinear terahertz (THz) spectroscopy techniques are required. Ideally, these techniques should use a minimal volume and capitalize on sensitive field-resolved detection. Here we performed open aperture z-scan transmission experiments on static liquid cells, and detect the THz fields with electro-optical techniques. We show that it is possible to quantify the nonlinear response of liquid water at ~1 THz even when large signals originate from the sample holder windows

Research data: Search for nonlinear thz absorption by electromagnons in multiferroic hexaferrites

Datasets measured at the TELBE THz facility consisting of raw (time-sorted) data and binned data that was used for further analysis. The xlsx-file contains measured THz powers. Metadata can be found in labbook file zip archive. Final data analysis was performed by Jakub Vít