During the last decade advances in the field of sensor design and improved base materials have pushed the radiation hardness of the current silicon detector technology to impressive performance. It should allow operation of the tracking systems of the Large Hadron Collider (LHC) experiments at nominal luminosity (1034 cm-2s-1) for about 10 years. The current silicon detectors are unable to cope with such an environment. Silicon carbide (SiC), which has recently been recognized as potentially radiation hard, is now studied. In this work it was analyzed the effect of high energy neutron irradiation on 4H-SiC particle detectors. Schottky and junction particle detectors were irradiated with 1 MeV neutrons up to fluence of 1016 cm-2. It is well known that the degradation of the detectors with irradiation, independently of the structure used for their realization, is caused by lattice defects, like creation of point-like defect, dopant deactivation and dead layer formation and that a crucial aspect for the understanding of the defect kinetics at a microscopic level is the correct identification of the crystal defects in terms of their electrical activity. In order to clarify the defect kinetic it were carried out a thermal transient spectroscopy (DLTS and PICTS) analysis of different samples irradiated at increasing fluences. The defect evolution was correlated with the transport properties of the irradiated detector, always comparing with the un-irradiated one. The charge collection efficiency degradation of Schottky detectors induced by neutron irradiation was related to the increasing concentration of defects as function of the neutron fluence.

In this thesis I studied La0.7Sr0.3MnO3/Alq3/AlOx/Co organic spin valves, which are multifunctional devices showing an interesting interplay between magnetoresistive effects and memristive switching. In particular this work aims at elucidating the elusive mechanisms for spin injection and transport in this archetypal structure. While spin injection in organic materials was demonstrated by different spectroscopic techniques, the origin of magnetoresistive effect in organic spin valves is still debated. In fact, the Hanle effect, considered to be the only reliable proof for spin transport across the organic spacer layer, has not been observed in such a device, yet. I investigated the thickness and temperature dependence of charge transport and magnetoresistive properties, and demonstrated the absence of the Hanle effect. Moreover I studied how the resistance and magnetoresistance of our devices were affected by memristive switching, which turned out to be a fundamental tool to enlighten the comprehensive picture. Two clearly distinguishable conduction regimes have been found for non magnetoresistive and magnetoresistive devices. The former is compatible with models for charge transport in organic materials, the latter can be described by an equivalent circuit where metallic paths and hopping channels act in parallel. In the framework of this model, a coherent description for the interplay between MR and memristive switching can be given. SV signals can be explained as tunnel magnetoresistance (TMR) or ballistic magnetoresistance (BMR) occurring across shortened regions of the organic bulk, which is an explanation compatible with the absence of Hanle effect. This work demonstrates that SV signals can be explained without resorting to spin injection and transport into the organic layer.

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One of the problems in the analysis of nucleus-nucleus collisions is to get information on the value of the impact parameter b. This work consists in the application of pattern recognition techniques aimed at associating values of b to groups of events. To this end, a support vec- tor machine (SVM) classifier is adopted to analyze multifragmentation reactions. This method allows to backtracing the values of b through a particular multidimensional analysis. The SVM classification con- sists of two main phase. In the first one, known as training phase, the classifier learns to discriminate the events that are generated by two different model:Classical Molecular Dynamics (CMD) and Heavy- Ion Phase-Space Exploration (HIPSE) for the reaction: 58Ni +48 Ca at 25 AMeV. To check the classification of events in the second one, known as test phase, what has been learned is tested on new events generated by the same models. These new results have been com- pared to the ones obtained through others techniques of backtracing the impact parameter. Our tests show that, following this approach, the central collisions and peripheral collisions, for the CMD events, are always better classified with respect to the classification by the others techniques of backtracing. We have finally performed the SVM classification on the experimental data measured by NUCL-EX col- laboration with CHIMERA apparatus for the previous reaction.

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