Magnetic force microscopy characterization of core–shell cobalt-oxide/hydroxide nanoparticles

Angeloni, Livia; Passeri, Daniele; Scaramuzzo, Francesca A.; Schiavi, Pier Giorgio; Pagnanelli, Francesca; Rossi, Marco

doi:10.1016/j.jmmm.2020.167299

Cited by 5 publications

(4 citation statements)

References 72 publications

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“…For these films, the resistivity varies from ρ = 98 µΩ cm (thickness d = 10 nm) up to ρ = 43.14 µΩ cm for d = 100 nm thin film, having 1/d dependence [57]. These values are higher than the bulk resistivity for bulk Co (ρ = 5.88 µΩ cm) or Ni (ρ = 7.14 µΩ cm) [47].…”

Section: Discussionmentioning

confidence: 99%

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Microstructural and Morphological Characterization of the Cobalt-Nickel Thin Films Deposited by the Laser-Induced Thermionic Vacuum Arc Method

et al. 2023

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Laser Induced-Thermionic Vacuum Arc (LTVA) technology was used for depositing uniform intermetallic CoNi thin films of 100 nm thickness. LTVA is an original deposition method using a combination of the typical Thermionic Vacuum Arc (TVA) system and a laser beam provided by a QUANTEL Q-Smart 850 Nd:YAG compact Q-switched laser with a second harmonic module. The novelty is related to the simultaneous deposition of a bi-component metallic thin film using photonic processes of the laser over the plasma deposition, which improves the roughness but also triggers the composition of the deposited thin film. Structural analysis of the deposited thin films confirms the formation of face-centered cubic (fcc) as the main phase CoNi and hexagonal Co3Ni as the minority phase, observed mainly using high-resolution transmission electron microscopy. The magneto-optical measurements suggest an isotropic distribution of the CoNi alloy thin films for the in-plan angular rotation. From the low coercive field of Hc = 40 Oe and a saturation field at 900 Oe, the CoNi thin films obtained by LTVA are considered semi-hard magnetic materials. Magnetic force microscopy reveals spherical magnetic nanoparticles with mean size of about 40–50 nm. The resistivity was estimated at ρ = 34.16 μΩ cm, which is higher than the values for bulk Co and Ni.

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Section: Discussionmentioning

confidence: 99%

“…In this study, we used CoCr cantilevers with a radius of less than 40 nm and a scan rate of 1 Hz. In standard Magnetic Force Microscopy measurements, the phase shift ∆ϕ of the oscillating cantilever is recorded at a fixed lift height ∆z [47].…”

Section: Atomic and Magnetic Force Microscopymentioning

confidence: 99%

Microstructural and Morphological Characterization of the Cobalt-Nickel Thin Films Deposited by the Laser-Induced Thermionic Vacuum Arc Method

et al. 2023

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“…Previous studies revealed that the optimum height for the used cantilevers and Pd-Fe NPs, at which van der Waals forces could be neglected but magnetic interaction is still strong, was between 20 and 30 nm of lift height [20]. The magnetic signal was measured via phase shift of the cantilever oscillations, which is proportional to the gradient of force between the probe and the sample [22][23][24][25]. The NPs were magnetized by a magnet set below the slices of the strength of 0.58 T.…”

Section: Magnetic Force Microscopy (Mfm)mentioning

confidence: 99%

Magnetic Decoration of Escherichia coli Loaded with Palladium Nanoparticles

Campaña

Joudeh

Mikheenko

et al. 2021

2021 IEEE 11th International Conference Nanomaterials: Applications &Amp; Properties (NAP)

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Palladium (Pd) is a scarce metal, which is able to catalyze a variety of important chemical reactions. In the bulk form, Pd is anomalous paramagnetic, but in the form of nanoparticles, it has been reported as ferromagnetic. Detecting the magnetism of Pd nanoparticles is, however, difficult due to their reduced dimension. In addition, the ferromagnetic nature is a size-dependent property and, for Pd, the strength of magnetism decreases with slight increments in size. A "green" methodology for the preparation of small Pd nanoparticles was followed in this study. It is based on the ability of bacteria to take up Pd 2+ ions from its surrounding solution and to enzymatically reduce it to metallic Pd 0 nanoparticles. The efficiency of the production can be determined by transmission electron microscopy and, as a new technique, magnetic force microscopy. Notwithstanding, the study of nanoparticles of the size of just a few nanometers with these techniques is still difficult. Here we present a methodology for the enhancement of the magnetic signal of biologically produced Pd-based nanoparticles through the decoration of Escherichia coli bacteria cross-sections with Fe nanoparticles. This methodology allows the visualization of bacteria that are loaded with magnetic nanoparticles even when conventional transmission electron microscopy has difficulties to resolve them inside the microorganisms.

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“…Such magnetic measurements performed on dried powders or colloidal suspensions are necessary for optimizing the chemical synthesis, as well as for concluding about the magnetic state. MFM on the other hand is a technique able to image individual clusters and to address their magnetization states at the nanometer scale. − This technique has been used for revealing magnetic properties of individual NPs − and of magnetically correlated grain systems . Nevertheless, MFM has also the potential to qualitatively investigate the magnetization state of clusters made of several NPs, in addition to their morphology, size characteristics, and separation. , Moreover, in some cases, the magnetic interaction forces measured by the microscope can also be used for quantitative magnetization studies under magnetic fields. , …”

Section: Introductionmentioning

confidence: 99%

Imaging Large Iron-Oxide Nanoparticle Clusters by Field-Dependent Magnetic Force Microscopy

et al. 2021

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Iron-oxide nanoparticles are intensively considered for high-performance biomedical applications, where simultaneous functionalities, such as magnetic state, large surface area for maximal protein/enzyme binding, high magnetization values to provide large signals, and good dispersion in liquid media, are usually required. In this context, the association of individual nanoparticles into large clusters is of particular interest. Here, we present a magnetic force microscopy (MFM) approach capable to image individual nanoparticulate clusters as large as 350 nm at room temperature and under variable magnetic fields. It is shown that an in situ removal of electrostatic interactions─particularly important for large particle sizes supported by dielectric substrates─in MFM experiments based on phase detection allows us to image the magnetic state of individual clusters. After taking into account the magnetization behavior of the microscope tip, the phase signal reveals a gradual and uniform rotation of the magnetization with the magnetic field and the absence of a hysteretic behavior for all investigated clusters.

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Magnetic force microscopy characterization of core–shell cobalt-oxide/hydroxide nanoparticles

Cited by 5 publications

References 72 publications

Microstructural and Morphological Characterization of the Cobalt-Nickel Thin Films Deposited by the Laser-Induced Thermionic Vacuum Arc Method

Microstructural and Morphological Characterization of the Cobalt-Nickel Thin Films Deposited by the Laser-Induced Thermionic Vacuum Arc Method

Magnetic Decoration of Escherichia coli Loaded with Palladium Nanoparticles

Imaging Large Iron-Oxide Nanoparticle Clusters by Field-Dependent Magnetic Force Microscopy

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