Granular Co–C nano-Hall sensors by focused-beam-induced deposition

Abstract

We investigated the performance of Hall sensors with different Co-C ratios, deposited directly in nanostructured form, using Co(2)(CO)(8) gas molecules, by focused-electron or ion-beam-induced deposition. Due to the enhanced intergrain scattering in these granular wires, the extraordinary Hall effect can be increased by two orders of magnitude with respect to pure Co, up to a magnetic field sensitivity of 1 Omega T(-1). We show that the best magnetic field resolution at room temperature is obtained for Co ratios between 60% and 70% and is better than 1 microT Hz(-1/2). For an active area of the sensor of 200 x 200 nm(2), the room temperature magnetic flux resolution is phi(min) = 2 x 10(-5)phi(0) in the thermal noise frequency range, i.e. above 100 kHz.

Understanding the electron-stimulated surface reactions of organometallic complexes to enable design of precursors for electron beam-induced deposition

“…4f), CO is the dominant gas phase species produced during electron irradiation, with little NO observed. This observation helps to explain why EBID deposits created from Co(CO) 3 NO have much higher N/C ratios than the 1:3 ratio present in the precursor [40][41][42][43][44][45]. Figure 5 describes the elementary steps that we believe underpin the EBID process.…”

Lateral resolution in focused electron beam-induced deposition: scaling laws for pulsed and static exposure

“…In such a way, local functional nanostructures can be formed without multistep processing, which is necessary in common resistbased electron beam lithography. Among the functional materials that have been fabricated using FEBID are ferromagnetic wires [2][3][4], metallic [5], and graphitic material [6] for low-resistance nanocontacts, as well as granular wires for strain sensors [7], magnetic sensors [8], gas sensors [9], and material with photonic/plasmonic functionality [10][11][12][13].…”

Absolute cross sections for dissociative electron attachment and dissociative ionization of cobalt tricarbonyl nitrosyl in the energy range from 0 eV to 140 eV

“…[4][5][6] With the advancement of nanotechnology tools and in particular focused electron beam induced deposition (FEBID) (for recent reviews on the method, see Utke et al 7 and van Dorp and Hagen 8 ), it has become possible to deposit more localized, three-dimensional structures. Cobalt octacarbonyl and cobalt tricarbonyl nitrosyl have thus been used in FEBID to deposit catalysts for carbon nanotube growth, 9 and to fabricate magnetic force microscopy (MFM) tips, 10,11 crossbar Hall nanosensors, 12 electrode contacts, 10 and cobalt nanowires. 13 While deposit purities of up to 95% have been demonstrated for Co 2 (CO) 8 , 14 there are currently several drawbacks limiting the use of this purely carbonyl containing cobalt precursor in FEBID.…”