We report an intriguing giant dielectric and magnetodielectric (MD) response on double perovskite Pr2CoMnO6(PCMO) system. The Arrhenius plot indicates that the origin of giant dielectric is internal barrier layer capacitance. Meanwhile, at the highest applied magnetic field 9T, the giant dielectric constant around Tm ~ 150 K is enhanced almost ~ 20% (at 10 kHz frequency) compared with that at zero field. The observed positive MD effect is considered to be associated with the direct consequence of negative magnetoresistance changes (~ -20% at 150 K) which was calculated by temperature dependent impedance spectras. Concomitantly, a pronounced ferromagnetic ordering is observed near Tc ~ 150 K coinciding with Tm of £`¡¬(T). These experimental results suggest that the magnetoresistive and MD effect response is very strongly by magnetic property of PCMO.

La problématique des condensateurs céramiques à très hautes performances est récurrente dansde nombreux secteurs de l’énergie électrique. Elle prend toute son acuité en microélectronique « nomade», où les circuits doivent être de plus en plus miniaturisés. Ces condensateurs, peuvent occuperjusqu’à 50 % de l’espace sur le circuit imprimé, réduire leurs dimensions devient donc un impératif.Dans ce contexte de nouveaux matériaux à permittivité colossale ont été découverts, commepar exemple CaCu3Ti4O12 (CCTO). Le mécanisme IBLC (Internal Barrier Layer Capacitance),décrivant des grains semi-conducteurs et des joints de grains isolants, permet aujourd’hui d’expliquerces fortes permittivités. Cependant l’origine de la semi-conductivité des grains ainsi quele caractère isolant des joints de grains donne encore matière à controverse. Ce travail a donc undouble objectif, d’une part concevoir un matériau possédant des propriétés diélectriques similairesà CCTO, et d’autre part comprendre les différents mécanismes responsables de ces permittivitésexceptionnelles. La première partie de ce manuscrit présente les caractéristiques d’usages descondensateurs, elle à également pour objectif de lister les mécanismes qui ont été proposés parla communauté scientifique pour tenter d’expliquer la forte permittivité de CCTO. La deuxièmepartie présente d’une part les techniques de caractérisations qui ont été utilisées pour analyserles composés présentés dans ce manuscrit, en insistant plus particulièrement sur la spectroscopied’impédance, largement utilisée dans cette étude. Elle présente d’autre part les techniques de synthèsesqui ont été expérimentées pour synthétiser un nouveau matériau à permittivité colossale :Ba4YMn3O11,5±δ. Les caractérisations structurale et micro-structurale de Ba4YMn3O11,5±δ serontévoquées dans la troisième partie de ce manuscrit. Enfin, les diverses optimisations qui ontété réalisées sur Ba4YMn3O11,5±δ, pour tenter d’améliorer ces propriétés diélectriques, serons évoquées.Nous détaillerons dans cette dernière partie les substitutions ayant été réalisées sur le sitedu baryum et du manganèse, ainsi que la création d’une phase possédant un cation différent del’actuel yttrium et présentant également des propriétés diélectriques très intéressantes. / The problem of ceramic capacitors with very high performance is recurrent in many areas ofElectrical Energy. It takes all its acuteness in « nomadic » microelectronics (cell phone, tablet, mp3player...) where the circuits must be increasingly miniaturized. These capacitors can take up to50 % of the space on the PCB, reducing their size becomes an imperative. In this context newmaterials with colossal permittivity were discovered, such CaCu3Ti4O12 (CCTO). The mechanismIBLC (Internal Barrier Layer Capacitance), describing semiconductor grains and insulating grainboundaries can now explain these high permittivities. However, the origin of the semiconductivitygrains and the insulating character of grain boundaries give even controversial. The aim is thus twofold,on one hand to synthesize a material possessing similar dielectric properties to CCTO, and onthe other hand to understand the various mechanisms responsible for these exceptional permittivity.The first part of this thesis presents various characteristics of capacitors uses, it also aims to listthe mechanisms that have been proposed by the scientific community to try to explain the highpermittivity of CCTO. The second part presents firstly the characterization techniques whichwere used to analyze all the compounds described in this manuscript, with particular emphasison impedance spectroscopy. It presents on the other hand synthesis techniques that have beentried to synthesize a new material with colossal permittivity : Ba4YMn3O11,5±δ. Structural andmicro-structural characterizations of Ba4YMn3O11,5±δ will be discussed in the third part to themanuscript. Finally, the various optimizations that were performed on Ba4YMn3O11,5±δ, to try toimprove the dielectric properties, will be discussed. We detail in this last part substitutions havingbeen made on the site of barium and manganese and the creation of a phase having a differentcation in the present yttrium site and having dielectric properties very interesting also.

Traditional transport companies usually focus on achieving economies of scale in supply chain management. At the same time, the managers of transport companies aiming to achieve sustainability often do not consider the barriers needed to overcome to achieve a sustainable supply chain. However, due to the increasing demand for sustainable products and business methods, sustainable supply chain management increasingly plays a crucial role in changing and diverting the focus on environmental, social and economic impact. Transport companies around the globe are increasingly aiming to reduce carbon emissions and eliminate biodiversity loss. The sustainability issues with transport in supply chain management have been a critical field of research for decades, and with the integration of technology, new ways of achieving sustainability are possible. This thesis analyses a phenomenon using multiple cases to investigate the barriers transport companies face to adopting IoT. Also, it deals with how communication service providers might be able to offer solutions to the barriers presented in this thesis.  A qualitative method has been used to approach the research topic. The findings will represent the ways of achieving a more efficient and sustainable supply chain, particularly in the transport sector. Interviews were conducted with multiple industry experts. The study aims to identify the barriers to adopting IoT, which can create a sustainable supply chain for transport companies. The results emphasise the barriers transport companies have to deal with internally and externally. Internally a company might struggle to strategise an infrastructural investment, train the existing workforce, and collaborate knowledge share among different departments. Externally, transport companies or communication service providers (CSP) will face limited resources, stakeholders' investment in the IoT ecosystem, demand for IoT and sustainable supply chain, privacy issues, compatibility issues and lack of skilled labour.