Magnetic Nanotubes Research Articles

Comparative study of electronic, thermoelectric, and transport properties in germanene and carbon nanotubes

This study investigates the electronic, thermoelectric, and transport properties of Germanene nanotubes (GeNTs) using a tight-binding calculations and explores their potential advantages over carbon nanotubes (CNTs) in thermoelectric applications. The effect of external electric and magnetic fields, nanotube radius, and temperature on heat capacity, electrical conductivity, power factor, and Seebeck coefficient are systematically investigated. The heat capacity C(T) of GeNTs shows a more pronounced increase with the application of external fields, especially electric field and exceeds that of CNTs. GeNTs also exhibit a lower threshold temperature for non-zero electrical conductivity attributed to their smaller energy gap, which results from easier thermal excitation of charge carriers. This property becomes more pronounced as the electrical conductivity of GeNTs increases more rapidly with temperature than that of CNTs, particularly under stronger external fields. Additionally, the thermoelectric properties of GeNTs can be further enhanced under external fields. While CNTs possess higher Seebeck coefficients and Lorenz numbers, GeNTs demonstrate distinct advantages in tunable heat capacity and conductivity, making them promising candidates for efficient thermoelectric and nanoelectronic devices. These results underscore the potential of GeNTs as an effective alternative to CNTs for advanced energy conversion applications, demonstrating their promise as high-performance thermoelectric materials for energy conversion applications.

Construction and Biological Evaluation of Different Nanoshell Thickness Ni@SiO2 Nanotubes as Good Protein Separation Carriers for Bovine Hemoglobin.

Nickel nanomaterials play an important role in biological applications, but they have high toxicity and poor biocompatibility. To overcome these defects, we coated the surface of Ni nanotubes with different thicknesses of SiO2 to reduce cytotoxicity, improve biocompatibility, and broaden their biological application value. This study aimed to construct Ni nanotubes with different thicknesses of SiO2 nanoshells; investigate the effects of silicon layer thickness, incubation time, and cell line category on the cytotoxicity of the as-synthesized materials, and evaluate the biocompatibility of the materials by biological enzymes. The Ni@SiO2-NH2 was selected for use as an adsorbent for the adsorption and purification of histidine-rich proteins, such as Bovine Hemoglobin (BHb). Magnetic Ni nanotubes were prepared by the template-chemical deposition method. A modified version of the Stöber process was used for the SiO2 coating of Ni@SiO2 nanotubes, and adjusted by changing the volume of TEOS for different thicknesses of SiO2 nanoshells. Different cell lines containing tumor cells and normal cells were used in the toxicity experiment, which confirmed the low cytotoxicity and good biocompatibility of Ni@SiO2. To achieve high efficiency of immobilization and purification of histidine- rich proteins, Ni@SiO2-NH2 was obtained by introducing the amino functional group. The Ni@SiO2-NH2 was found to possess lower cytotoxicity and higher adsorption capacity compared to other synthesized materials. Besides, the Ni@SiO2-NH2 also exhibited good selectivity of histidine-rich proteins. This work has not only provided ideas for reducing the cytotoxicity and improving the biocompatibility of biological nanomaterials, but also laid a foundation for subsequent biological applications.

Skyrmion motion induced by spin-waves on magnetic nanotubes

Abstract We investigate the skyrmion motion driven by spin waves on magnetic nanotubes through micromagnetic simulations. Our key results include demonstrating the stability and enhanced mobility of skyrmions on the edgeless nanotube geometry, which prevents destruction at boundaries — a common issue in planar geometries. We explore the influence of the damping coefficient, amplitude, and frequency of microwaves on skyrmion dynamics, revealing a non-uniform velocity profile characterized by acceleration and deceleration phases. Our results show that the skyrmion Hall effect is significantly modulated on nanotubes compared to planar models, with specific dependencies on the spin-wave parameters. These findings provide insights into skyrmion manipulation for spintronic applications, highlighting the potential for high-speed and efficient information transport in magnonic devices.

Magnetic sodium titanate nanotubes for simultaneous recovery of multiple low-level heavy and radioactive metal ions

Heavy and radioactive metal ions pollutants in water are a serious environmental problem and cause various health issues which lead to fetal human diseases. Herein, magnetic sodium titanate nanotubes (Fe3O4/NaTNTs) as magnetically separable nanostructure composite material were synthesized and used as adsorbent for simultaneous removal of multiple metal ions contaminants. HRTEM, SEM, FTIR, EDX, XRF, XRD, thermal gravimetric analysis (TGA), and zeta potential analysis were used for Fe3O4/NaTNT characterization. Thirteen metal cations including Th4+ and U4+, have been tested for competitive and simultaneous sorption on Fe3O4/NaTNTs nanostructure. In the mixed metal ions system, the removal efficiency of Co2+ and Pb2+ is the highest (Co2+; 95.9 %, Pb2+; 94.2 %). The relative selectivity for the removal of Cs+ ions (32 %) is more than that of Sr2+ ions (25 %). Thus, the data indicates the potential of Fe3O4/NaTNTs to be used in wastewater treatment, especially to simultaneously remove multiple heavy metal ions. Fe3O4/NaTNTs sorbent can be used for the rapid removal of heavy elements to mitigate large quantities of water pollution in emergencies, such as nuclear accidents and leaks.

Frequency combs based on magnon-skyrmion interaction in magnetic nanotubes

Abstract Within the magnonics community, there has been a lot of interests in the magnon–skyrmion interaction. Magnons and skyrmions are two intriguing phenomena in condensed matter physics, and magnetic nanotubes have emerged as a suitable platform to study their complex interactions. We show that magnon frequency combs can be induced in magnetic nanotubes by three-wave mixing between the propagating magnons and skyrmion. This study enriches our fundamental comprehension of magnon–skyrmion interactions and holds promise for developing innovative spintronic devices and applications. This frequency comb tunability and unique spectral features offer a rich platform for exploring novel avenues in magnetic nanotechnology.

Immobilization of ionic liquids (ILs) on magnetic mesoporous silica nanotubes: A high throughput and reusable nanocatalyst for the green synthesis of indeno[1,2-b]indolone derivatives

The acidic ionic liquid supported on the magnetic mesoporous silica nanotubes (M-MSNTs/IL) was prepared as a new magnetic catalyst and fully characterized with FE-SEM, HR-TEM, EDS, TGA, BET, VSM, FT-IR, EDX, elemental mapping and XPS. The template of catalyst was magnetic aminated MWCNTs (M-MWCNTs/CONHBu), which removed through calcination process and magnetic mesoporous silica nanotubes (M-MSNTs) were obtained and functionalized using adenine based ionic liquid. The prepared catalyst was successfully applied as a new reusable heterogeneous catalyst for the one-pot three-component indeno[1,2-b]indole-9,10-dione derivatives in water at 75 °C. All of desired products were obtained in good to excellent yields (79–96 %) after relatively short reaction times. M-MSNTs/IL also exhibited a remarkable performance with TOF of 61.2 h-1 and TON of 86.7. The use of M-MSNTs/IL catalyst in the synthesis of indeno[1,2-b]indole-9,10-dione derivatives revealed several advantages including mild reaction conditions, high yield of pure products, clean reaction conditions, avoiding the production of toxic waste, chemical stability of the catalyst, low amount and reusability of catalyst. In addition, the applied nanocatalyst was recovered with an external magnet and reused 6 times without considerable reduction in its catalytic activity.

Polyethyleneimine in designed nanocomposite based magnetic halloysite nanotubes for extraction and determination of gallic acid in green tea

An innovative and simple nanocomposite denoted as MHNTs@PEI was synthesized for gallic acid (GA) analytical sample pretreatment. Polyethyleneimine (PEI) functionalized was binded onto magnetic halloysite nanotubes (MHNTs) to inhence adsorption capacity. MHNTs@PEI was obtained only through two steps modification (amination and PEI modification). Characterizations showed that there are layers of synthetic PEI on the tubular structure of the material and magnetic spheres on its surface, both indicating successful synthesis of the nanocomposite. Furthermore, the adsorption isotherms and kinetic modeling showed that the Langmuir model and pseudo-first-order model fit the adsorption data, respectively. MHNTs@PEI achieved an adsorption capacity of 158 mg·g−1. Overall, the abundant adsorption sites significantly improved the adsorption performance of the MHNTs@PEI. Regeneration tests demonstrated that the MHNTs@PEI exhibits effective adsorption, even after undergoing five consecutive cycles. Optimization of key parameters (ratio, volume of elution, elution time and frequency) in the process of adsorption and desorption was also conducted. The limit of detection (LOD) and that of the quantification (LOQ) were 0.19 and 0.63 μg·mL−1, respectively, and the recoveries were 95.67–99.43 %. Finally, the excellent magnetism (43.5 emu·g−1) and the adsorption feature of MHNTs@PEI enabled its successful utilization in analytical sample pretreatment through the extraction of GA from green tea.

Switching of magnetic bilayer nanotube ring with antiferromagnetically coupled layers in an annular field

The magnetization switching behavior of magnetic nanotube rings with core–shell structure is investigated by solving the Landau-Lifshitz-Gilbert (LLG) equation, focusing on the effects of the magnetic structure, interfacial exchange interactions, anisotropy constants, and transverse field on the coercivity of the system. The reduction of the coercivity of the magnetic nanorings can increase the magnetization switching rate and reduces the energy consumption when the magnetic nanorings are used as magnetic storage units. In the study, it is found that the antiferromagnetic exchange interaction between the spins in the core can greatly reduce the coercivity of the system, and the coercivity decreases with the increase of the interface exchange interaction. When the anisotropy constant of the antiferromagnetic core gradually increases, the coercivity of the system varies nonlinearly and a point of minima occurs. Finally, the effect of the transverse magnetic field on the hysteresis behavior of the system is also discussed, and it is found that the coercivity of the system decreases gradually with the increase of the transverse magnetic field, but the hysteresis loop of the system is distorted when the critical value is exceeded.

Synthesis and characterization of Restricted Access Magnetic Nanotubes (M-RACNTs) for the extraction of secondary metabolites from Lasiodiplodia sp. fermentation broth

This work proposed the synthesis and the characterization of Restricted Access Magnetic Nanotubes (M-RACNTs) to be used as sorbent in the magnetic dispersive solid-phase extraction (MDSPE) of organic compounds from the fermentation broth of the endophyte Lasiodiplodia sp. Synthesis was performed by functionalizing commercial multiple-walled carbon nanotubes with magnetic nanoparticles (M-CNTs) and by coating the M-CNTs with a layer of bovine serum albumin. The materials were characterized by infrared spectroscopy with Fourier Transform, thermogravimetry, zeta potential, and scanning electron microscopy. Different crude extracts were obtained, depending on the sample pH and the elution solvent tested. Chloroform and ethyl acetate extracts showed activity against a Gram-positive pathogen (Staphylococcus aureus). The crude extract's constitution was investigated. By GC/MS analysis were found hydrocarbons, aldehydes, alcohols, among others, while by LC-MS/MS analysis were found flavonoids, macrocyclic lactones, oleic acids, jasmonic acid derivatives and amino acids. A multivariate optimization, through fractional factorial planning, for four independent variables, was performed for a hydrocarbon (hexadecane) and one possible jasmonic acid derivative, both with antimicrobial activity related in the literature. The results showed that it was possible to obtain crude extracts with high concentrations of these analytes in a single extraction procedure. The increase in the analytical signal was 3.7 times for hexadecane and 1.4 times for the possible jasmonic acid derivative. The M-RACNTs also demonstrated their ability to prevent the adsorption of macromolecules, such as lysozyme, which was confirmed through SDS-PAGE analysis.

Mean Field Study of a Cylindrical Ferrimagnetic Nanotube with Different Anisotropies

In this paper, the ferrimagnetic mixed spins (1, 5/2) Blume-Capel model is proposed to investigate the phase diagrams and hysteresis behaviors of a magnetic cylindrical nanotube with a core-shell structure using the mean-field approximation based on the Bogoliubov inequality for the Gibbs free energy. The core sites are occupied by σ= ±1, 0 spins, whereas the shell sites are filled by S= ±5/2, ±3/2, ±1/2 spins. The effects of exchange couplings (Jin, JS) and single-ion anisotropies (DC, DS) on core, shell, and total magnetizations are investigated, as well as hysteresis behaviors. The entropy, free energy, and specific heat are analyzed to establish the stability of the solutions. The presentation and discussion of phase diagrams is detailed. The system shows a first-order and second-order phase transitions, as well as tricritical and critical end- points. In addition, the system shows compensation and reentrant behaviors. Various multiple hysteresis loop behaviors are seen according on the Hamiltonian parameters, such as the presence of triple, quintuple, and septuple hysteresis loops.

Magnetic materials as an environmentally friendly cooling and heating systems: Tuning magnetocaloric properties in the magnetic nanotubes

The magnetocaloric properties - which is important for designing energy efficient and environment friendly heating and cooling systems- of the magnetic nanotube are constituted by arbitrary core spin values S_C and the shell spin values S_(S ) have been investigated by mean field approximation. Several quantities have been calculated during this investigation, such as isothermal magnetic entropy change, full width at half maximum value and the refrigerant capacity, in order to suggest more efficient heating and cooling. The variation of these quantities with the values of the spins and exchange interaction between the core and shell is determined. Besides, recently experimentally observed double peak behavior in the variation of the isothermal magnetic entropy change with the temperature is obtained for the nanotube.

Examining the adsorption efficiency of iron oxide-decorated magnetic halloysite nanotubes for tetracycline elimination from solutions

In our research, we investigated the potential of HNT-Fe3O4, a magnetic adsorbent composed of halloysite nanotubes(HNTs) and iron oxide nanoparticles, for removing tetracyclines(TCs) from water. We utilized a range of analytical techniques such as FT-IR, VSM, XRD, BET, TEM, TGA, and SEM to characterize the materials. Furthermore, we evaluated HNT-Fe3O4’s capability to remove TCs from water, particularly noting the influence of solution pH on its adsorption properties. Results indicated that the adsorption process adhered to the pseudo-second-order kinetics, with the Langmuir model best describing the adsorption isotherms. The reusability study revealed that after six repeated uses, HNT-Fe3O4 maintained most of its adsorption efficiency. An adsorption–desorption experiment further confirmed its potential as a valuable adsorbent for wastewater treatment. In summary, our study underscores the potential of HNT-Fe3O4 as a durable and effective medium for TCs removal in water treatment.

Magnetic induction heating and drug release properties of magnetic carbon nanotubes

Aim The use of magnetic carbon nanotubes for multi-modal cancer treatment, incorporating both hyperthermia and drug delivery functions, has drawn substantial interest. Yet, the present method of regulating hyperthermia temperature involves manually adjusting the magnetic field intensity, adding to the complexity and difficulty of clinical applications. This study seeks to design novel magnetic carbon nanotubes capable of self-temperature regulation, and investigate their drug loading and release characteristics. Methods Using the co-precipitation method, we synthesized magnetic carbon nanotubes with a Curie temperature of 43 °C. A comprehensive investigation was conducted to analyze their morphology, crystal structure, and magnetic characteristics. To enhance their functionality, chitosan and sodium alginate modifications were introduced, enabling the loading of the antitumor drug doxorubicin hydrochloride (DOX) into these magnetic carbon nanotubes. Subsequently, the loading and release properties of DOX were investigated within the modified magnetic nanotubes. Results Under alternating magnetic field, magnetic carbon nanotubes exhibit self-regulating properties by undergoing a magnetic phase transition, maintaining temperatures around 43 °C as required for hyperthermia. On the other hand, during magnetic induction heating, the release percentage of DOX reached 23.5% within 2 h and 71.7% within 70 h at tumor pH conditions, indicating their potential for sustained drug release. Conclusions The prepared magnetic carbon nanotubes can effectively regulate the temperature during hyperthermia treatment while ensuring controlled drug release, which presents a promising method for preparing nanomaterials that synergistically enhance magnetic hyperthermia and chemotherapy drugs.

Enhanced magnetic halloysite nanotubes for dye removal at different pH conditions

Halloysite nanotubes (HNTs) have been extensively investigated for potential utilization due to their unique structure and properties as a type of natural, eco-friendly clay. The synthesis and modification of magnetic halloysite nanotubes was studied using several experimental techniques including SEM, TEM, FT-IR, Raman spectroscopy, UV-Vis spectroscopy, and BET. Dye absorption experiments were conducted to understand bonding using EDS, XPS, XRD, and Raman spectroscopy. In this study, we evaluated Sunset Yellow FCF (SY) dye removal as a model to understand bonding structures among magnetic HNTs, magnetic particles, and dye molecules. We focus on the interactions of SY-magnetic HNTs and characteristics of magnetization by VSM after SY dye adsorption, which highlight the notable features of magnetic halloysite nanotubes. We used different pH environments to study the behavior of magnetic HNTs after dye absorption. The application of these modified HNTs is promising for future organic dye removal and wastewater treatment.

The Effect of Exchange Interaction on Phase Transition Behavior of Magnetic Nanotubes

In this paper, the phase diagram of the Blume-Capel model under exchange interaction between lattice points in different positions in magnetic nanotube lattice is studied with effective field theory. The research shows that the interaction between nearest neighbors and the lattice field strength strongly influences the system’s three critical points and phase transition temperature. Under certain conditions, there are three critical points in the system. That is, the relationship between the crucial points is linear from the second-order phase transition to the first-order phase transition. First-order phase transition replaces second-order phase transition in the system’s phase transition. The findings demonstrate that exchange interaction significantly affects the system’s phase transition, and they offer a theoretical framework for both industrial production and experimental study.

Nucleation and Growth Mechanisms of Bimetallic Sm-Co Nanowires and Nanotubes

Nucleation and growth mechanisms of bimetallic Sm-Co magnetic nanowires and nanotubes, electrocrystallizing into hard anodic alumina templates, are described. Nanowires are produced at two overpotentials −0.9 V and −3 V, into templates with pore diameters of 20 nm and 40 nm; for larger pores, 200 nm in diameter, nanowires result at −0,9 V while at −3 V nanotubes form. The electrodeposition process mainly develops under diffusional control, with the current monotonically decreasing with time. Experimental current/time curves are described by suitable models adapted to bimetallic phases, considering successive stages in the pore filling process. In membranes with small pore diameter, a linear diffusion zone ahead the growing nanowire surface allows to apply a modified Cottrell equation. Models based on recessed microelectrodes behaviour are proposed, considering the overlap of diffusion zones at the porous mouth. For large pore diameter (>100 nm), current transitory is described by a 1D model for nanowires grown at −0.9 V, while a new expression is derived for nanotubes developing at −3 V, where the hydrogen evolution provides an important contribution to the mechanism. The mechanisms proposed are consistent with nanowires´ and nanotubes´ morphology details observed in SEM images.

Sono-enhanced heterogeneous Fenton catalysis: magnetic halloysite nanotube synthesis and accelerated free radical generation.

Although heterogeneous Fenton catalysis has captured increasing attention compared to its homogeneous counterpart, it still confronts some inherent drawbacks in use, such as the dilemma in solid-liquid separation and greater mass transfer resistance. Driven by the acoustic cavitation effect, herein, a sono-enhanced heterogeneous Fenton catalysis process was built to overcome the above two shortcomings, by rapidly synthesizing magnetic Fenton-like catalysts and accelerating electron transfer during the catalytic reaction. The results show that, compared to the traditional chemical coprecipitation method, Fe3O4 with smaller particle size and better crystallinity grew on the surface of halloysite nanotubes (HNTs) by using the sonochemical strategy, leading to displaying the higher catalytic activity toward the degradation of methylene blue (MB, improved by ~2.5 times). In parallel, more •OH and •O2- were produced after the ultrasound was further introduced to the routine Fenton-like catalysis system, thus highly accelerating the removal of MB (improved by ~50%). Besides, benefiting from the robust chemical integration of Fe3O4 and HNTs, Fe3O4@HNTs-S had a lower iron ion leaching in use, showing superior catalytic stability. The speed, simplicity, and generality, together with the enhanced mass transfer rate, make the use of ultrasound an enabling methodology to improve the heterogeneous Fenton catalysis.

Insulin‑like growth factor axis: A potential nanotherapy target for resistant cervical cancer tumors (Review).

Cervical cancer is among the most frequently occurring neoplasms worldwide, and it particularly affects individuals in developing countries. Factors such as the low quality of screening tests, the high incidence of locally advanced cancer stages and the intrinsic resistance of certain tumors are the main causes of failure in the treatment of this neoplasm. Due to advances in the understanding of carcinogenic mechanisms and bioengineering research, advanced biological nanomaterials have been manufactured. The insulin-like growth factor (IGF) system comprises multiple growth factor receptors, including IGF receptor 1. These receptors are activated by binding to their respective growth factor ligands, IGF-1 and IGF-2, and insulin, and play an important role in the development, maintenance, progression, survival and treatment resistance of cervical cancer. In the present review, the role of the IGF system in cervical cancer and three nanotechnological applications that use elements of this system are described, namely Trap decoys, magnetic iron oxide nanoparticles and protein nanotubes. Their use in the treatment of resistant cervical cancer tumors is also discussed.

Magnetic semiconducting borophenes and their derivatives.

Two semiconducting borophenes with layer-dependent magnetism are predicted based on spin-polarized density functional theory. Both monolayer borophenes are ferromagnetic. One is composed of B3 and B15 triangular motifs, exhibiting bipolar spin polarization and a magnetic moment of 1.00 μB per primitive cell. The other consists of B15 triangular motifs, possessing a Curie temperature of about 437 K and a magnetic moment of 3.00 μB per primitive cell. B atoms located between the triangular motifs are essential for inducing ferromagnetism in monolayer borophenes. However, bilayer borophenes with high-symmetry stacking orders are nonmagnetic. Furthermore, magnetic boron nanotubes and fullerenes could be made of monolayer borophenes. Finally, we propose to fabricate these magnetic semiconducting borophenes from the buckled triangular structure of borophenes via selective electron beam ionization of B atoms by scanning transmission electron microscopy.

Design and Fabrication of a Retrievable Magnetic Halloysite Nanotubes Supported Nickel Catalyst for the Efficient Degradation of Methylviolet 6B and Acid Orange 7

AbstractMagnetic halloysite nanotubes based organic‐inorganic hybrid materials have elicited ripples of excitement in the area of water research and technology by the virtue of their hollow nanotubular structure, presence of adequate hydroxyl groups and tunable surface chemistry. Fascinated by these riveting benefits, a nickel based nanocatalyst has been designed wherein a bidentate chelating ligand “4‐aminoantipyrine (AA)” was anchored onto the surface of aminosilane functionalized magnetic halloysite nanotubes followed by its metalation. In a shorter time span of 30 min, the synthesized nanocatalyst showed outstanding degradation efficiency of 96.87 % and 96.22 % towards MV6B and AO7 respectively under neutral conditions. The ensuing nanocomposite in‐situ generates ⋅OH from H2O2 that aided in rapid degradation of MV6B and AO7 into innocuous products with unprecedented efficacy. Besides, the impressive magnetic attributes of designed Ni(II)@AA@APTES@MHNTs offer effortless magnetic retrievability with the aid of an external magnet and the catalyst could be recycled upto six consecutive runs. GC‐MS analysis helped in identifying the generated degradation products and provided valuable insights into the plausible degradation pathway of pollutants followed during the reaction. Through various studies, it is believed that the peerless advantages of Ni(II)@AA@APTES@MHNTs nanocatalyst will lay a foundation for treatment of wastewater containing devastating organic contaminants.