Highlights

The resistive switching mechanism of CBRAM clarified by using synchrotron characterizations

In  recent  years,  resistive  random  access  memories  have  received  extensive  interest  for applications  as  non-volatile  memories  or  neuromorphic  computing.  Conductive  Bridging Random Access Memories (CBRAM) based on a glassy Ag-GeSx  layer sandwiched between an  Ag  anode  and  an  inert  W  cathode  are  considered  to  be  one  of  the  most  promising technologies. Under the influence of an electric field Ag ions are produced at the anode and migrate in the electrolyte reaching the cathode and forming a conducting wire. This process is reversible by applying a bias with opposite polarity. However, the lack of understanding of the  switching  mechanisms  at  a  nanoscale  level  prevents  the  successful  transfer  of  this technology to the industry. CBRAM devices were characterized in their different resistive states using depth-selective X-Ray Absorption Spectroscopy (XAS) at the GILDA-CRG beamline at the ESRF in Grenoble.

Looking Inside the Perchlorinated Trityl Radical/Metal Spinterface through Spectroscopy

Persistent and stable organic molecules with an open-shell electronic configuration have long been known and extensively studied mainly in solution. Only recent is instead the study of organic radicals as laterally self-assembled monolayers immobilized on substrates towards their application in devices, e.g. in organic spintronics [1].

Nanopatterning reconfigurable magnetic landscapes via thermally assisted scanning probe lithography

The search for novel tools to control magnetism at the nanoscale is crucial for the development of new paradigms in optics, electronics and spintronics. To date, the fabrication of magnetic nanostructures has been achieved mainly through irreversible structural or chemical modifications.


Here, we propose a new approach, based  on thermally assisted magnetic scanning probe lithography (tam-SPL),  for creating reconfigurable  magnetic nanopatterns by crafting, at the nanoscale, the magnetic anisotropy landscape of a ferromagnetic layer exchange-coupled to an antiferromagnetic layer. By performing localized field cooling with the hot tip of a scanning probe microscope, magnetic structures, with arbitrarily oriented magnetization and tunable unidirectional anisotropy, are reversibly patterned without modifying the film chemistry and topography. This opens unforeseen possibilities for the development of novel metamaterials with finely tuned magnetic properties, such as magnonic crystals allowing active manipulation of spin waves. In this context, we present a proof-of-concept experiment, performed by micro-focused Brillouin light scattering (µ-BLS), showing that local control of the spin wave excitation and propagation can be obtained in reconfigurable magnetic tracks patterned with tam-SPL.

A Roadmap for Controlled and Efficient n-type Doping of Self-assisted GaAs Nanowires Grown by Molecular Beam Epitaxy

N-type doping of GaAs nanowires has proven to be difficult because the amphoteric character of silicon impurities, routinely used for the n-type doping of GaAs epilayers,  is enhanced by the nanowire growth mechanism and growth conditions. Among the various possible donor impurities for GaAs NWs, tellurium represents a good candidate since it is a very effective dopant in GaAs epilayers and does not present any risk of amphoteric behavior.

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