Hybrid Ni–Boron Nitride Nanotube Magnetic Semiconductor—A New Material for Spintronics

Abstract

Here, we report the presence of ferromagnetism in hybrid nickel–boron nitride nanotubes (BNNTs) with an ordered structure, synthesized by chemical vapor deposition using elemental boron, nickel oxide as the catalyst, and ammonia gas as the source for nitrogen. In previous studies, the nanotubes were synthesized with two metal oxide catalysts, whereas here, only a single catalyst was used. The nanotube’s structure was determined by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. Purity of the nanotubes synthesized at 1150 °C was exceptional and this was determined by Raman spectroscopy. The average diameter of the nanotubes was 63 nm. Based on the magnetic studies carried out, it can be confirmed that the synthesized hybrid material is ferromagnetic at room temperature. Cyclic voltammetry was carried out to confirm the dielectric nature of the nanotubes. These materials could pave ways to nanoscale devices. The well-known thermal stability of BNNTs would play a vital role in preventing thermal failures in such small-scale devices where overheating is a major concern. The presence of semiconducting and magnetic properties in a single material could be confirmed, which might be highly significant in the field of spintronics.

Research of Low-Dimensional Carbon-Based Magnetic Materials

“…(d) Isothermal magnetization of the nanotubes. (a–d) Reproduced from ref . Copyright 2020 American Chemical Society.…”

“…52 A first-principles study on substituted doping of BN nanotubes by transition metals appeared ten years ago. 53 Until recently, Ni 2 O 3 as catalyst and the chemical vapor deposition technique were used synthesize BNNT materials; the CNT-based magnetic material is formed without removing Ni, 26 and its magnetic properties are shown in Figure 3. The temperature-dependent magnetization zero field cooling (ZFC) and field cooling (FC) clearly show weak ferromagnetic behavior from room temperature to low temperature, as shown in Figure 3a.…”

“…(a) Hybrid nickel–boron nitride nanotubes (BNNTs). Reproduced from ref . Copyright 2020 American Chemical Society.…”

A current review on boron nitride nanotubes and their applications

“…However, in the CVD technique, instead of purging additional hydrogen into the reaction chamber, gaseous ammonia is used, which is NH 3 . The deduced reactions and related products can be seen in equations [55]. The obtained intermediary products are the same in both CVD and thermal plasma techniques.…”

“…Irrespective of the precursor type, a catalyst is necessary to initiate the nanotube growth. In an earlier work [55], a single nickel oxide was used as the catalyst to aid tube growth. The entire reaction takes place inside the tubular furnace under an inert atmosphere and ammonia gas assisted in nitriding the boron to give BNNTs.…”