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The research developed in this work is structured in the following parts: Chapter 2. In this chapter, the physico-chemical characterization and mechanical properties of magnetic hydrogels containing sepiolite-magnetite particles are studied. First of all, in this chapter the synthesis of sepiolite (fiber-like shaped) clay particles covered by magnetite nanoparticles, carried out by the co-precipitation method, is described. Afterwards, the adsorption of alginate molecules onto the composite particles is checked by means of zeta potential measurements. In addition, the most relevant magnetic properties of the particles are depicted. Then, the preparation of alginate hydrogels and alginate/(clay-magnetite) ferrogels, by crosslinking of alginate molecules with calcium ions, is detailed. Finally, the rheological properties, in the absence and presence of external magnetic field, as well as the microstructural study of the different hydrogels obtained with embedded particles are presented. Chapter 3. This chapter includes a similar study to that of chapter 2, but in this case for suspensions and magnetic hydrogels containing montmorillonite-magnetite platelets. Chapter 4. In this one we describe an ex-vivo study, using different techniques, of the biocompatibility of the suspensions and ferrogels containing sepiolite-magnetite particles. Chapter 5 is devoted to remark the most relevant achievements attained and also the main conclusions drawn from this research work. Finally, chapter 6 includes the references cited along whole thesis. ; Tesis Univ. Granada. ; Project FIS2017-85954-R. Ministerio de Economia, Industria y Competitividad, MINECO, and Agencia Estatal de Investigacion, AEI, Spain, cofounded by Fondo Europeo de Desarrollo Regional, FEDER, and European Union.

This contribution discusses the modelling and parameterization of dielectric and magnetic properties of ferroconcrete by using numerical electromagnetic field analysis software. The software is based on the Method of Moments (MoM). The shielding effectiveness (SE) of the ferroconcrete DUT was already measured in a study by order of the government. According to these results, the ferroconcrete DUT is modelled and calculated. Therefore the DUT is subdivided into two parts. The first part represents the reinforcement mesh; the second part represents the lossy concrete with complex permittivity. Afterwards, the reflection and transmission properties of numerical analysed building materials are validated and compared with the measurement results in a frequency range of 30-1000 MHz.

Micas have recently attracted the interest of materials scientists to be used as flexible substrates for the growth of nanomaterials. Synthetic fluorophlogopite is particularly appealing due to its high thermal stability and a significantly lower level of impurities compared to natural mica. Perhaps because of such high purity, little attention has been given to its magnetic properties, assumed to be diamagnetic. Herein, we report an in-depth study of the magnetic properties of commercial fluorophlogopite mica crystals as a function of magnetic field and temperature. Our study shows that the magnetic response of mica comprises diamagnetic and paramagnetic components. The latter is quite significant at low temperatures and can be analyzed within the framework of Curie's law and the Langevin theory, which indicate that it originates from isolated magnetic cations. Hence, special care must be taken to study the magnetic properties of mica-supported nanostructures. We propose a protocol to correct the magnetic contributions of mica substrates which can be useful in future developments of flexible magnetic devices. ; The authors thank Michael Mikhov for his useful comments regarding the analysis of the data. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement no. [819623]). We also acknowledge financial support from the Spanish Ministerio de Ciencia, Innovación y Universidades (MINCIU), through Project No. RTI2018-098537-B-C21, cofunded by ERDF from EU, and "Severo Ochoa" Programme for Centres of Excellence in R&D (Grant No. SEV-2015-0496) and from Generalitat de Catalunya through the projects 2017SGR00765 and 2017SGR1632. The authors also acknowledge Bernat Bozzo, Maite Simón, Vega Lloveras, Francisco Javier Campos and Anna Crespi from the Scientific Services at ICMAB-CSIC and Ignasi Villarroya from the Chemical Analysis Service at UAB. Z. M. was financially supported by China Scholarship Council (CSC) with No. 201606070094. Z. M.'s work was done as a part of the PhD program in Materials Science at Universitat Autònoma de Barcelona. ; Peer reviewed

This contribution discusses the modelling and parameterization of dielectric and magnetic properties of ferroconcrete by using numerical electromagnetic field analysis software. The software is based on the Method of Moments (MoM). The shielding effectiveness (SE) of the ferroconcrete DUT was already measured in a study by order of the government. According to these results, the ferroconcrete DUT is modelled and calculated. Therefore the DUT is subdivided into two parts. The first part represents the reinforcement mesh; the second part represents the lossy concrete with complex permittivity. Afterwards, the reflection and transmission properties of numerical analysed building materials are validated and compared with the measurement results in a frequency range of 30–1000 MHz.

This contribution discusses the modelling and parameterization of dielectric and magnetic properties of ferroconcrete by using numerical electromagnetic field analysis software. The software is based on the Method of Moments (MoM). The shielding effectiveness (SE) of the ferroconcrete DUT was already measured in a study by order of the government. According to these results, the ferroconcrete DUT is modelled and calculated. Therefore the DUT is subdivided into two parts. The first part represents the reinforcement mesh; the second part represents the lossy concrete with complex permittivity. Afterwards, the reflection and transmission properties of numerical analysed building materials are validated and compared with the measurement results in a frequency range of 30–1000 MHz.

The influence of post-processing conditions on the magnetic properties of amorphous and nanocrystalline microwires has been thoroughly analyzed, paying attention to the influence of magnetoelastic, induced and magnetocrystalline anisotropies on the hysteresis loops of Fe-, Ni-, and Co-rich microwires. We showed that magnetic properties of glass-coated microwires can be tuned by the selection of appropriate chemical composition and geometry in as-prepared state or further considerably modified by appropriate post-processing, which consists of either annealing or glass-coated removal. Furthermore, stress-annealing or Joule heating can further effectively modify the magnetic properties of amorphous magnetic microwires owing to induced magnetic anisotropy. Devitrification of microwires can be useful for either magnetic softening or magnetic hardening of the microwires. Depending on the chemical composition of the metallic nucleus and on structural features (grain size, precipitating phases), nanocrystalline microwires can exhibit either soft magnetic properties or semi-hard magnetic properties. We demonstrated that the microwires with coercivities from 1 A/m to 40 kA/m can be prepared. ; This research was funded by Spanish MCIU under PGC2018-099530-B-C31 (MCIU/AEI/FEDER, UE), by the Government of the Basque Country under PIBA 2018-44 and Elkartek (CEMAP and AVANSITE) projects and by the University of Basque Country under the scheme of "Ayuda a Grupos Consolidados" (Ref.: GIU18/192).

This paper deals with the effect of a biocompatible surface coating layer on the magnetic properties of ultrasmall iron oxide nanoparticles. Particles were synthesized by laser pyrolysis and fully oxidized to maghemite by acid treatment. The surface of the magnetic nanoparticles was systematically coated with either phosphonate (phosphonoacetic acid or pamidronic acid) or carboxylate-based (carboxymethyl dextran) molecules and the binding to the nanoparticle surface was analyzed. Magnetic properties at low temperature show a decrease in coercivity and an increase in magnetization after the coating process. Hysteresis loop displacement after field cooling is significantly reduced by the coating, in particular, for particles coated with pamidronic acid, which show a 10% reduction of the displacement of the loop. We conclude that the chemical coordination of carboxylates and phosphonates reduces the surface disorder and enhances the magnetic properties of ultrasmall maghemite nanoparticles. ; This work was partially supported by grants from the Spanish Ministry of Economy and Competitiveness (MAT2011-23641), the Madrid regional government (S009/MAT-1726 to MPM) and the 7th framework programme of the European Community (Nanomag 604448). ; Peer reviewed

Motivated by the recent synthesis of single layer TiSe2,we used state-of-the-art density functional theory calculations, to investigate the structural and electronic properties of zigzag and armchairedged nanoribbons (NRs) of this material. Our analysis reveals that, differing from ribbons of other ultra-thin materials such as graphene, TiSe2 NRs have some distinctive properties. The electronic band gap of the NRs decreases exponentially with the width and vanishes for ribbons wider than 20 Å. For ultranarrow zigzag-edged NRs we find odd-even oscillations in the band gap width, although their band structures show similar features. Moreover, our detailed magnetic-ground-state analysis reveals that zigzag and arm chair edged ribbons have non-magnetic ground states. Passivating the dangling bonds with hydrogen at the edges of the structures influences the band dispersion. Our results shed light on the characteristic properties of T phase NRs of similar crystal structures. ; Flemish Science Foundation (FWO-Vl); Methusalem foundation of the Flemish government; FWO Pegasus Long Marie Curie Fellowship; FWO Pegasus Short Marie Curie Fellowship; TUBITAK (114F397)

Iron and stony‐iron meteorites form the Widmanstätten pattern during slow cooling. This pattern is composed of several microstructures whose length‐scale, composition and magnetic properties are dependent upon cooling rate. Here we focus on the cloudy zone: a region containing nanoscale tetrataenite islands with exceptional paleomagnetic recording properties. We present a systematic review of how cloudy zone properties vary with cooling rate and proximity to the adjacent tetrataenite rim. X‐ray photoemission electron microscopy is used to compare compositional and magnetization maps of the cloudy zone in the mesosiderites (slow cooling rates), the IAB iron meteorites and the pallasites (intermediate cooling rates), and the IVA iron meteorites (fast cooling rates). The proportions of magnetic phases within the cloudy zone are also characterized using Mössbauer spectroscopy. We present the first observations of the magnetic state of the cloudy zone in the mesosiderites, showing that, for such slow cooling rates, tetrataenite islands grow larger than the multidomain threshold, creating large‐scale regions of uniform magnetization across the cloudy zone that render it unsuitable for paleomagnetic analysis. For the most rapidly cooled IVA meteorites, the time available for Fe‐Ni ordering is insufficient to allow tetrataenite formation, again leading to behavior that is unsuitable for paleomagnetic analysis. The most reliable paleomagnetic remanence is recorded by meteorites with intermediate cooling rates ( urn:x-wiley:ggge:media:ggge22125:ggge22125-math-0001 2–500 °C Myr urn:x-wiley:ggge:media:ggge22125:ggge22125-math-0002) which produces islands that are "just right" in both size and degree of Fe‐Ni order. ; This work was supported by the European Research Council under the European Union's Seventh Framework Programme (FP/2007‐2013)/ ERC grant agreement numbers 320750 and 312284. ; Peer reviewed

In this paper the results of magnetic properties study for a series samples of R(Co0.88Fe0.12)2 type intermetallic compounds with a heavy rare-earth elements (R = Gd, Tb, Dy, Ho, Er) are presented. Such materials having a plateau-like temperature dependences of magnetic entropy change in the temperature range lower Curie point are considered as a promising functional materials for magnetic refrigerators. Their phase composition was controlled by X-ray diffraction analysis with a help of Bruker D8 Advance diffractometer. Magnetic field magnetization dependences - M(H) were measured using a SQUID magnetometer (MPMS-XL-7, Quantum Design) within the temperature range of 5 - 600 K in magnetic fields up to 5600 kA/m. The crystal lattice parameter - a, Curie temperature - TC, coercivity - Hc and residual magnetization - Mr values are analyzed as a functions of R-element atomic number. For compounds with Tb, Dy, Ho and Er the second picks on the high field susceptibility temperature dependences - χhf (T) were found in the temperature range lower their TC. © Published under licence by IOP Publishing Ltd. ; Ministry of Science and Higher Education of the Russian Federation ; № 02. ; 3.6121.2017/8.9 ; This work has been supported by the State contract No. 3.6121.2017/8.9 between UrFU and Ministry of Science and High Education of Russian Federation, and by Act 211 Government of the Russian Federation, contract № 02.A03.21.0006.