Pasquale Orgiani is responsible of Pulsed Laser Deposition technique within NFFA Laboratory.
His main research activity is the deposition of thin films and heterostructures by Molecular Beam Epitaxy (MBE) and Pulsed Laser Deposition (PLD) techniques and the investigation of the transport properties of both magnetic and superconducting films, with/without external magnetic field.
In the last years he carried out a strong activity on electronic investigation of oxide thin films and heterostructures. His research on superconducting and magnetic oxide is focused on the role of structural properties and transport properties (metal-insulator transition, quantum interference effects at low temperatures, and so on) of such compounds.
We report the integration of high-quality epitaxial La2/3Sr1/3MnO3 (LSMO) thin films onto SrTiO3 buffered Silicon-on-Sapphire (SOS) substrates by combining state-of-the-art thin film growth techniques such as molecular beam epitaxy and pulsed laser deposition. Detailed structural, magnetic and electrical characterizations of the LSMO/STO/SOS heterostructures show that the LSMO film properties are competitive with those directly grown on oxide substrates. X-ray magnetic circular dichroism measurements on Mn L2,3 edges show strong dichroic signal at room temperature, and angular-dependent in-plane magnetic properties by magneto-optical Kerr magnetometry reveal isotropic magnetic anisotropy. Suspended micro-bridges were thus finally fabricated by silicon micromachining, thus demonstrating the potential use of integrating LSMO magnetic layer on industrially compatible SOS substrates for the development of applicative MEMS devices.
Appl. Surf. Sci., 574, 151608, (2022)
Metal to insulator transition at the surface of V2O3 thin films: An in-situ view
M. Caputo, J. Jandke, E. Cappelli, S.K. Chaluvadi, E. Bonini Guedes, M. Naamneh, G. Vinai, J. Fujii, P. Torelli, I. Vobornik, A. Goldoni, P. Orgiani, F. Baumberger, M. Radovic, G. Panaccione
V2O3 has long been studied as a prototypical strongly correlated material. The difficulty in obtaining clean, well ordered surfaces, however, hindered the use of surface sensitive techniques to study its electronic structure. Here we show by means of X-ray diffraction and electrical transport that thin films prepared by pulsed laser deposition can reproduce the functionality of bulk V2O3. The same films, when transferred in-situ, show an excellent surface quality as indicated by scanning tunnelling microscopy and low energy electron diffraction, representing a viable approach to study the metal-insulator transition in V2O3 by means of angle-resolved photoemission spectroscopy. Combined, these two aspects pave the way for the use of V2O3 thin films in device-oriented heterostructures.
ACS Appl. Mater. Interfaces, (2021)
Evidence of Mn-Ion Structural Displacements Correlated with Oxygen Vacancies in La0.7Sr0.3MnO3 Interfacial Dead Layers
P. Rajak, D. Knez, S.K. Chaluvadi, P. Orgiani, G. Rossi, L. Méchin, and R. Ciancio
The properties of half-metallic manganite thin films depend on the composition and structure in the atomic scale, and consequently, their potential functional behavior can only be based on fine structure characterization. By combining advanced transmission electron microscopy, electron energy loss spectroscopy, density functional theory calculations, and multislice image simulations, we obtained evidence of a 7 nm-thick interface layer in La0.7Sr0.3MnO3 (LSMO) thin films, compatible with the formation of well-known dead layers in manganites, with an elongated out-of-plane lattice parameter and structural and electronic properties well distinguished from the bulk of the film. We observed, for the first time, a structural shift of Mn ions coupled with oxygen vacancies and a reduced Mn valence state within such layer. Understanding the correlation between oxygen vacancies, the Mn oxidation state, and Mn-ion displacements is a prerequisite to engineer the magnetotransport properties of LSMO thin films.
Strada Statale 14 - km 163,5 - 34149 Trieste, ITALY
ph. +39 040 3756487 fax +39 040 226767
NFFA is a Progetto Internazionale financed by MIUR through CNR
(Istituto Officina dei Materiali, Trieste) and Elettra-Sincrotrone Trieste
and managed by the Commissione NFFA chaired by Giorgio Rossi
(Università di Milano and IOM-CNR).