Magnetism of Cr-doped diamond-like carbon

Abstract

Chromium-doped hydrogenated diamond-like carbon ͑Cr-DLC͒ and chromium carbide hydrogenated DLC alloys were synthesized by plasma-assisted vapor deposition and investigated by x-ray absorption near edge structure spectroscopy, extended x-ray absorption fine structure, and superconducting quantum interference device ͑SQUID͒ magnetometry. Structural and magnetic properties of the doped and alloy materials were investigated as a function of the Cr concentration ͑0.1-20 at. %͒. Toward the upper end of the concentration range, Cr precipitates in the form of chromium carbide ͑Cr 3 C 2 ͒ nanoclusters. For low Cr concentrations, the systems are ferromagnetic at very low temperatures, whereas the chromium carbide clusters appear to be antiferromagnetic with uncompensated spins at the surface. Cr-DLC films and alloys with various Cr concentrations are used to make heterojunctions on silicon, and the produced diodes are investigated by I-V measurements. The heterojunctions exhibit negative magnetoresistance that saturates at less than 500 Oe and may be suitable for spin-electronics applications.

Ab initio investigation of magnetism in Cr‐doped diamond‐like carbon

“…Further calculations were performed for the supercells consisting of 1, 3, 4, and 6 Cr ions yielding the atomic concentrations of 1.5625, 4.6875, 6.25, and 9.375 at.% at which the presence of low-temperature ferromagnetism was observed experimentally [4]. We determined the total energies for the non-spin-polarized and the spin-polarized case.…”

Electrical and magnetic properties of electrodeposited nickel incorporated diamond-like carbon thin films

“…Ni-DLC films may find usage in optoelectronics and in magnetic devices [30,31,36,37]. It is possible to control the size of incorporated metal particles inside DLC matrix [36,37]. We expect that the magnetic properties of the films can be tailored by manipulation of the size of metal particles.…”

“…Although few groups have studied magnetic properties of DLC and metal doped DLCs but we are not aware of any magnetic characterizations of electrodeposited Ni-DLC thin films yet. Colon Santana et al [36] reported magnetism studies of chromium (Cr) doped DLC thin films synthesized by plasma assisted vapor deposition method. They found that Cr doped DLC thin films exhibited ferromagnetic property at very low temperatures, whereas Cr 3 C 2 clusters appeared to be antiferromagnetic.…”

“…Here we also aim to study the magnetic properties of our magnetic metal particle incorporated Ni-DLC thin films for its potential magnetic applications. Ni-DLC films may find usage in optoelectronics and in magnetic devices [30,31,36,37]. It is possible to control the size of incorporated metal particles inside DLC matrix [36,37].…”

Sizeable magnetic circular dichroism of artificially precipitated Co clusters in amorphous carbon

“…In particular, recent developments in a-C materials with favorable magnetoelectronic properties have attracted attention. [11][12][13][14][15] with a graphitic C matrix, 16 the chemical bonding between the p-shell of carbon atoms and metallic cobalt atoms at the cluster surface can strongly influence the physical properties of such a material. These facts reveal that interface intermixing can dramatically influence magnetic measurements and lead to erroneous conclusions.…”