Giant magnetoresistance behavior of an iron/carbonized polyurethane nanocomposite

Abstract

This letter describes the magnetoresistance (MR) behavior of the heat-treated polyurethane composites reinforced with iron nanoparticles. The flexible nanocomposites were fabricated by the surface-initiated-polymerization method. The uniformly distributed nanoparticles within the polymer matrix, well characterized by field emission scanning electron microscopy, favor a continuous carbon matrix formation, rendering the transition from insulating to conductive composites. The coercive forces reflect strong particle loading and matrix dependent magnetic properties. By simply annealing in a reducing environment, the obtained nanocomposites possess a MR of 7.3 % at room temperature and 14 % at 130 K occurring at a field of 90 kOe.

Magnetic Graphene Nanoplatelet Composites toward Arsenic Removal

“…The coercivity (coercive force, H c ) is observed to be 496.0 Oe after forming the core@shell structure, which is significantly larger than that of the bare Fe NPs (5.0 Oe) with a comparable size. 56,57 This observation indicates that the NPs become much harder (ferromagnetic at room temperature) after they were decorated on the GNP sheet. The observed large H c is due to the decreased interparticle dipolar interaction arising from the increased interparticle distance as compared to the close contact of the pure iron NPs, and also due to the interfacial exchange coupling 58 between the ferromagnetic iron core and the antiferromagnetic iron oxide.…”

Electrospun magnetic fibrillar polyarylene ether nitriles nanocomposites reinforced with Fe‐phthalocyanine/Fe3O4 hybrid microspheres

“…The T g for the pure PEN fibers is 173. 5 C and increases to 176.1, 179.8, and 181.1 C for the nanocomposite fibers with a particle loading of 5, 10, and 30 wt %, respectively. It is attributed to the interactions between the functional groups which are formed on the hybrid microspheres and PEN matrix 21,24 and the nanoconfinement of microspheres on the polymer chains, which restrict the segmental motions at the organic-inorganic interface.…”

“…This indicates that the hybrid microspheres become magnetically harder after being dispersed in the PEN matrix within the nanocomposite fibers. The enhanced coercivity of nanoparticles is due to the decreased interparticle dipolar interaction, which arises from the enlarged nanoparticle spacer distance for the single domain nanoparticles, 30,31,33 as compared with the closer contact of the hybrid microspheres.…”

“…These PNCs have attracted wide interest in both academic and industrial fields for their diverse potential applications in energy storage devices, 2 electronics, 3,4 and microwave absorbers. 5,6 Electrospinning, first reported in 1934 by Formhals et al, has attracted much attention in both scientific and industry areas, because it is a very convenient and effective method to produce ultra fine fibers or fibrous structures of various polymers with diameter ranging from a few nanometers to several micrometers. [7][8][9] Electrospun fibers, especially in the nanoscale size, have found wide applications in various fields.…”

Magnetic and Electron Transport Behaviors of Conductive‐Polymer Nanocomposites

“…Granular polymer nanocomposites have also been investigated for possible GMR applications [43,96]. Conductive iron nanoparticle-reinforced vinyl ester resin nanocomposites are observed to possess MRs of only 0.9%, which increase to 1.7% after carbonization ( Figure 12.17a).…”