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Dipartimento di Fisica - Politecnico di Milano

Materiali e dispositivi per l’elettronica di spin e la nano-biotecnologia

The activity of the NanoBiotechnology and spintronics group (NaBis) takes place at Polifab, the facility for the micro and nanofabrication of Politecnico di Milano, and is focused on two main topics: i) the fabrication and testing of heterostructures and devices for spin electronics (ferroelectrics, antiferromagnets, Rashba semiconductors, magnonic waveguides, MEMs); ii) the realization of high-sensitivity detectors and single-bead manipulators for application in nano-medicine.

Two cluster tools machine are available for hetostructure growth and characterization.

1) In LASSE (Layered Artificial Structures for Spin Electronics), the available in vacuo synthesis techniques are Pulsed Laser Deposition (PLD) and Molecular Beam Epitaxy (MBE). Analysis and characterization of surfaces and interfaces are performed in situ by means of electron spectroscopy techniques, also with spin resolution: low and high energy electron diffraction (LEED, RHEED), Auger spectroscopy, x-ray and ultraviolet photoemission (XPS, UPS), photoelectron diffraction (XPD), spin-resolved inverse photoemission. Complementary experiments are carried out at synchrotron radiation facilities (mostly at ELETTRA-Trieste and ESRF-Grenoble) after an ultra-high vacuum transfer of the samples. The growth of samples is supported by several ex situ characterization tools such as: x ray diffraction (XRD), secondary electron microscopy (SEM), atomic and magnetic force microscopy (AFM, MFM), secondary ion mass spectroscopy (SIMS), magneto-optical Kerr effect (MOKE, also available in situ in the growth machine).

2) A magnetron sputtering machine Orion from AJA international, equipped with 10 different targets (CoFeB, MgO, Ta, Ru, Au, SiO2,...), allows for the realization of complex heterostructures, with spatial uniformity up to 3" and high repeatibility of the process flows.

Magneto-Optical Kerr Effect microscopy (MOKE) and Vibrating Sample Magnetometry (VSM) are available for magnetic characterization of the samples. Moreover, it is possible to realize magnetic micro- and nano-structures starting from the synthetized heterostructures, by means of photo- and electron beam- lithography processes. The prototypes of the devices can be characterized by means of transport measurements under an applied magnetic field at variable temperature (1.6K-550K).