Publications by authors named "A Cervellino"

Non-stoichiometric 214-nickelates with Ruddlesden-Popper (RP) type frameworks emerged as potential candidates for mixed electronic/ionic conductors in the intermediate temperature range. In this work we investigated structural aspects of the oxygen ion mobility diffusion mechanisms in non-stoichiometric NdNiO nickelates by X-ray (laboratory and synchrotron) as well by neutron diffraction. Temperature dependent synchrotron powder diffraction revealed a phase diagram of unprecedented complexity, involving a series of highly organized, 3D modulated phases related to oxygen ordering below 800 K.

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The microscopic mechanism of heavy band formation, relevant for unconventional superconductivity in CeCoIn and other Ce-based heavy fermion materials, depends strongly on the efficiency with which electrons are delocalized from the rare earth sites and participate in a Kondo lattice. Replacing Ce (4,  = 5/2) with Sm (4,  = 5/2), we show that a combination of the crystal electric field and on-site Coulomb repulsion causes SmCoIn to exhibit a Γ ground state similar to CeCoIn with multiple electrons. We show that with this single-ion ground state, SmCoIn exhibits a temperature-induced valence crossover consistent with a Kondo scenario, leading to increased delocalization of holes below a temperature scale set by the crystal field,  ≈ 60 K.

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Metallic copper generally adopts an FCC structure. In this work, we detect highly unusual BCC-structured Cu nanoparticles as a transient intermediate during the H reduction of a Cu precursor, [CuOBu], grafted onto the surface of partially dehydroxylated silica. The Cu BCC structure, assigned by Cu K-edge XANES and EXAFS, as well as synchrotron PXRD, converts upon heating into the most commonly found FCC allotrope.

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The van-der-Waals material CrSBr stands out as a promising two-dimensional magnet. Here, we report on its detailed magnetic and structural characteristics. We evidence that it undergoes a transition to an A-type antiferromagnetic state below T ≈ 140 K with a pronounced two-dimensional character, preceded by ferromagnetic correlations within the monolayers.

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