MINT

MINT is a laboratory dedicated to the growth of complex oxides and magnetic layers for the study of interfacial effect in functional heterostructures.

MINT is a laboratory installed in Trieste, MM building in 2024. It is dedicated to the growth and characterization of thin films, particularly epitaxially-grown complex oxides and magnetic thin films. It includes a versatile MOKE setup, an XPS chamber with state-of-the-art electronics and detector, and a rich instrumentation for surface characterization. It's research activity is mostly dedicated to the study of interface-driven modifications of the magnetic properties of functional heterostructures.

Technical description

MINT is composed by 3 UHV chambers interconnected: Oxide MBE, MASK (with in vacuum MOKE) and off‐line XPS station (VolPe).

Oxide MBE is designed for the growth of complex oxides in pure ozone or oxygen as oxidizing ambient. The growth chamber is equipped with in-situ noninvasive measurement of atomic fluxes in real-time for single component materials (quartz crystal monitor) and for multi-component compound (atomic absorption spectroscopy). The deposition of individual monolayers is monitored by in situ reflection high energy electron diffraction (RHEED) system. Deposited materials spread from ferroelectric films to (anti)ferromagnetic complex oxides and materials for catalysis.

MASK allows for metal and simple rock-salt oxide depositions. The chamber is equipped for the standard tools for sample preparation in UHV conditions (sputtering with Ar ions, annealing stage by e-beam bombardment, quartz microbalance, leak valve for gas inlet and e-beam evaporators). In the chamber an Auger spectroscopy/LEED system allows structural and chemical characterization. Together with the sample deposition tools, the MASK chamber is equipped with an in-situ MOKE apparatus for azimuthal Kerr magnetometry in UHV, for both longitudinal (in-plane) and polar (out-of-plane) configurations, with fields up to 0.5 T and temperatures in the range from 30 to 500 K, be means of a Helium liquifier. Finally, thanks to a 2 contact sample-holder, it is possible to measure transport properties (I vs V curve and magnetoresistance) of thin films and junctions.

VolPe is equipped with a double anode (Mg,Al) x-ray source and with a electrostatic hemispherical analyzer (mean radius 200 mm) to permit XPS measurements. The samples can be transferred in situ from the MBE chambers or can be directly introduced from the nearby load-lock chamber.

The whole setup is compatible with UHV suitcase transfers.

MINT is part of the NFFA infrastructures (NFFA-Trieste, NFFA-EU, NFFA-DI).

Development of new methods, instrumentation, software

VolPe is operated by a homemade software, which controls both the analyser electronics and the detector, developed by Elettra synchrotron group.

The laboratory developed methods for electrical and photocurrent measurements on photovoltaic/piezoelectric heterostructures.

Research Activity

The research activity of MINT laboratory is mostly focused on the growth and characterization of magnetic thin films deposited on functional materials. By exploiting the degrees of freedom of the functional heterostructure (as for instance the inverse piezoelectric response under electric field), the modifications of the magnetic response is studied via MOKE measurements. Such heterostructures are either grown on functional substrates, either commercially bought or from collaborations, or composed by thin films in both parts.

Together with this activity, the presence of a laboratory XPS allows for characterizations of magnetic materials, either along different growth processes (sputtering/annealing, thin film deposition) or after exposure to gases in MASK chamber (for instance for catalytic applications).

The laboratory was previously located at APE beamlines of Elettra synchtrotron. Thanks to the full compatibility between the beamlines and the MINT apparatus, joint experiments are envisioned at the Elettra 2.0 restart.