Fabrication and electrical transport properties of embedded graphite microwires in a diamond matrix
Abstract
Micrometer width and nanometer thick wires with different shapes were produced ≈ 3~ below the surface of a diamond crystal using a microbeam of He+ ions with 1.8~MeV energy. Initial samples are amorphous and after annealing at T≈ 1475~K, the wires crystallized into a graphite-like structures, according to confocal Raman spectroscopy measurements. The electrical resistivity at room temperature is only one order of magnitude larger than the in-plane resistivity of highly oriented pyrolytic bulk graphite and shows a small resistivity ratio((2 K)/(315 K) ≈ 1.275). A small negative magnetoresistance below T=200~K was measured and can be well understood taking spin-dependent scattering processes into account. The used method provides the means to design and produce millimeter to micrometer sized conducting circuits with arbitrary shape embedded in a diamond matrix.