Nanogels based on biocompatible, dual pH- and temperature-sensitive poly(2-(diethylamino)ethyl) methacrylate (PDEAEMA) have been successfully used as nanocontainers for the encapsulation of magnetite, Fe3O4 magnetic nanoparticles (MNPs). For this purpose, citric acid-coated MNPs were encapsulated into previously synthesized PDEAEMA-based nanogels using a poly(ethyleneglycol)-based stabilizer. After the encapsulation of the magnetite MNPs, the so-called magneto-nanogels (MNGs) were proved to be multiresponsive on temperature, pH, and magnetic field and colloidally stable. Moreover, preliminary studies on the biocompatibility of these MNGs with cells of human peripheral blood were performed and evidenced quite tolerable biocompatibility, thus suggesting potential use in biomedical applications. (C) 2015 Wiley Periodicals, Inc.

Magnetoresistance effects observed in superconductor/ferromagnet (SC/FM) hybrids, SC/FM bilayers and FM/SC/FM trilayers, have attracted much interest in recent years. Here we focus on the stray-fields-based superconducting magnetoresistance effect (sMRE) observed in Co(d(Co))/Nb(d(Nb))/Co(d(Co)) trilayers with sufficiently thick Co outer layers so that out-of-plane magnetic domains (MDs) and MDs walls (MDWs) emerge all over their surface when subjected to a parallel external magnetic field, H-ex equal to the coercive field, H-c. Asking for the optimum conditions to maximize the sMRE, we explore the interference between three basic length scales of the SC and FM structural units: the thickness of the SC interlayer (d(SC)), the zero-temperature coherence length (xi(0)) and the width of out-of-plane MDs (D-MDs). To this effect, simulations-based modeling of the transverse stray dipolar fields, H-z,H-dip that emerge at the interior of the out-of-plane MDs is performed. Both cases of homogeneous and inhomogeneous micromagnetic characteristics (saturation magnetization, M-sat and width, DMDs) of the out-of-plane MDs are investigated. Furthermore, the influence of the microstructure of the bottom and top Co layers on the macroscopic coercive field of the TLs is addressed. The obtained modeling results respond well when tested against experimental data. The generic criteria reported here on the optimum matching of d(SC), xi(0) and D-MDs aiming to maximize the sMRE magnitude in relevant FM/SC/FM trilayers, can assist the design of relevant cryogenic devices. (C) 2016 Elsevier B.V. All rights reserved.

The ferroelectric compound family Pb(ZrxTi1-x,)O-3 (PZT) is one of the most investigated and widely used piezoelectric materials. Optimization of the piezoelectric coefficients is observed for x similar to 0.52 (Pb(Zr0.52Ti0.48)O-3) and is further promoted by the increase of grain size (OS). However, in some cases the piezoelectric properties of Pb(Zr0.52Ti0.48)O-3 deteriorate upon processing due to the decrease of density, p, that is mostly ascribed to the appearance of byproduct phases. In the present study we discuss the influence of the processing conditions on the piezoelectric properties for polycrystalline Pb(Zr0.52Ti0.48)O-3, specifically focusing on the sintering temperature, 1100 degrees C Tsin <= 1250 degrees C. To this end, we use atomic force microscopy (AFM), Archimedes' method, x-ray diffraction (XRD) and a newly introduced local technique, based on a conventional optical microscope, which is further developed here to accommodate non-clamped specimens. The data obtained via this technique in the regime of relatively high electric fields evidence that the absolute piezoelectric coefficients, 141(i = x, y) show a non -monotonic behavior with an unexpectedly high maximum value broken vertical bar d broken vertical bar similar to 1100 pm V 1 at 7 = 1180 degrees C. These features are accompanied by a progressive increase of coercivity, reaching maximum value Ecj 4.5-5.0 kV cm I (i = x, y) at Tsin = 1250 degrees C. 'lb explain these findings, the Idzil coefficients are compared with the microstructure and compositional information, coming from AFM, Archimedes' method and XRD data. We conclude that the significantly high 141 values observed for samples prepared at Tsin = 1180 degrees C are motivated by the increase of mean GS, < GS >, while for Tsin > 1180 degrees C the decrease of density, p, ascribed to the appearance of byproduct phases, dominates and deteriorates Id2 I. These experimental results on broken vertical bar d broken vertical bar(T-sin) are reliably reproduced by a phenomenological model with reasonable assumptions for < GS > (7) 1 and rho(T(si)n). The unexpectedly high piezoelectric coefficients, broken vertical bar d(zi)broken vertical bar similar to 1100 pm V-1, reported here for the first time, are provocative and call for utilization of the introduced approach in the investigation of the respective properties of other compounds.

The competitive nature of ferromagnetism and superconductivity in Ferromagnet/Superconductor (FM/SC) hybrids has attracted much interest in the last decades. In particular, the superconducting magnetoresistance (SMR) observed in FM/SC/FM trilayers (TLs) is related to the manipulation of the transport properties of the SC interlayer by the magnetic domain structure of the FM outer layers with out-of-plane anisotropy. In our recent work [Sci. Rep. 5, 13420 (2015)], a phenomenological model was proposed that describes successfully the scaling of the SMR magnitude with the relevant macroscopic parameters and microscopic length scales of the SC and FM structural units. Based on this model, here we investigate the contribution of the parameters that affect indirectly the SMR magnitude and do not appear in the original model. To this end, the parameters of both the SC interlayer (i.e., the thickness, dSC, the mean free path, l, the coherence length, xi(0), etc.) and the FM outer layers (i.e., the thickness, d(FM)) are examined. The theoretical simulations presented here and experimental data unveil the indirect contribution of these parameters on the magnitude of the SMR and confirm the predictive power of the original phenomenological model. Accordingly, this model can be employed as a generic formula to combine successfully all involved parameters in every kind of FM/SC/FM TLs, ultimately optimizing the magnitude of the SMR. (C) 2016 AIP Publishing LLC.