Green electrochemical template synthesis of CoPt nanoparticles with tunable size, composition, and magnetism from microemulsions using an ionic liquid (bmimPF6)

Altres ajuts: Substrates have been prepared in IMB-CNM (CSIC),supported by the (CSIC) NGG-258 project.Electrodeposition from microemulsions using ionic liquids is revealed as a green method for synthesizing magnetic alloyed nanoparticles, avoiding the use of aggressive reducing agents. Microemulsions containing droplets of aqueous solution (electrolytic solution containing Pt(IV) and Co(II) ions) in an ionic liquid (bmimPF) define nanoreactors in which the electrochemical reduction takes place. Highly crystalline hcp alloyed CoPt nanoparticles, in the 10-120 nm range with a rather narrow size distribution, have been deposited on a conductive substrate. The relative amount of aqueous solution to ionic liquid determines the size of the nanoreactors, which serve as nanotemplates for the growth of the nanoparticles and hence determine their size and distribution. Further, the stoichiometry (PtCo) of the particles can be tuned by the composition of the electrolytic solution inside the droplets. The control of the size and composition of the particles allows tailoring the room-temperature magnetic behavior of the nanoparticles from superparaparamagnetic to hard magnetic (with a coercivity of H = 4100 Oe) in the as-obtained state. © 2014 American Chemical Society

Precoding and reception for ULA-based wide-aperture MIMO

An approach is presented to compute the capacity-achieving precoder and receiver for wide-aperture MIMO with uniform linear arrays in O(N2min) operations as opposed to the O(N2minNmax) required by the singular-value decomposition of the channel matrix; Nmin and Nmax are the smallest and largest of the numbers of transmit and receive antennas. This hefty reduction in complexity comes at no cost in performance provided a parabolic wavefront model applies over the arrays, which is the case if the array apertures are not overly large relative to the range. Then, as the number of antennas grows larger, the proposed approach evolves into DFT-based precoders and receivers that are even more easily computable.This work was supported in part by the European Research Council under Grant 694974; in part by the Government of Spain under Project RTI2018-102112-B-I00; in part by the ICREA Academia Program; and in part by the UPF-Fractus Chair on Tech Transfer and 6G