In this paper we report on the fabrication of a spintronic device based on multiwalled carbon nanotubes functionalized/coupled with a rare earth element complex. The spin valve behavior is verified by magneto-resistance fluctuations at low temperatures. We report the magneto-transport features of spin valve devices based on multiwalled carbon nanotube covalently functionalized with a gadolinium complex. The switching is encoded in the composite from which devices are fabricated by di-electrophoresis. The magnetic field dependent electronic transport characteristics are investigated through the Cryogenic high field measurement system at 300 mK. Structural characterization of the material through transmission and scanning electron microscopy and Raman spectroscopy of the pristine and composite is done. The electronic transport shows a magnetic field dependence which is characteristic of spin valve at 300 mK and furthermore this spin valve feature is temperature dependent.
We utilize nano-manipulting probes for the fabrication of a range of devices including multilayered graphene coplanar waveguides, suspended multilayered graphene hall bars and air-gap single crystal organic field effect transistors. We find that devices fabricated using this technique are of high quality and can be used to probe not only application based phenomena (such as transistor behaviour), but also fundamental quantum transport properties. Magnetoresistance measurements show that the multilayered graphene devices exhibit either quantum linear magnetoresistance (QLMR) or Shubnikov de-Haas oscillations depending on the topology (i.e. either wrinkled or smooth) of the graphene sheet. From this data we calculate the carrier density (ns) in the wrinkled graphene to be in the range 5.2 × 10<sup>9</sup> cm<sup>-2</sup> (at <i>B</i>~0) to 3.5 × 10<sup>13</sup> cm<sup>-2</sup> (at <i>B</i>=12 T) with effective masses of 0.001<i>m</i><sub>e</sub> and 0.121<i>m</i><sub>e</sub>, respectively. The smooth multilayer graphene devices have a carrier density 1.39 - 2.85 × 10<sup>12</sup> cm<sup>-2</sup> and effective mass (0.022<i>m</i><sub>e</sub> ≤ <i>m</i>*≤ 0.032<i>m</i><sub>e</sub>) as calculated from the analysis of the Shubnokov de-Haas oscillations. The high frequecny coplanar waveguide devices fabricated using this technique demonstrated high transmission up to 50 GHz, highlighting the potential for HF application. Organic field effect transistors were also fabricated using the manipulation technique, the transfere characteristics were measured, it was found that the devcies with channel length of 1 μm have non-linear transfere characterisitcs and pass a maximum current of between 0.1 and 10 nA. These OFET devices showed pronounced switching behaviour with mobilities of up to 3 cm<sup>2</sup>V<sup>-1</sup>s<sup>-1</sup> in the best devices.