Ferromagnetic resonance spectra of linear magnetosome chains

• Elizaveta M. Gubanova and
• Nikolai A. Usov

Beilstein J. Nanotechnol. 2024, 15, 157–167, doi:10.3762/bjnano.15.15

• is well known [14][15][33][34][35] that the power absorbed by the assembly per unit time and per unit volume is proportional to the area of the assembly hysteresis loop where m is the reduced magnetic moment of the assembly. To numerically calculate the power absorbed by an assembly of

Specific absorption rate of randomly oriented magnetic nanoparticles in a static magnetic field

• Ruslan A. Rytov and
• Nikolai A. Usov

Beilstein J. Nanotechnol. 2023, 14, 485–493, doi:10.3762/bjnano.14.39

• magnetic field, denoted by the symbol h. It is assumed that at the initial moment of time, the unit magnetization vector of the particle is given by αx = 1. Irregular perturbations of the components of the unit magnetization vector occur due to thermal fluctuations of the particle magnetic moment at T

• hysteresis loop, shown in Figure 3d. However, in a sufficiently strong perpendicular magnetic field, Hdc = 400 Oe (Figure 4d), a deep potential well appears in which the magnetic moment of the particle is actually blocked, αx ≈ 0, αz ≈ 1, since the direction of the dc magnetic field becomes energetically

The influence of structure and local structural defects on the magnetic properties of cobalt nanofilms

• Alexander Vakhrushev,
• Aleksey Fedotov,
• Olesya Severyukhina and
• Anatolie Sidorenko

Beilstein J. Nanotechnol. 2023, 14, 23–33, doi:10.3762/bjnano.14.3

• representing the magnetic spin of the particle, ωi is the magnetic moment, and ℏ is the Planck constant. This approach to calculate spin temperature was proposed in [44]. The approach described in this paper and originally proposed by the authors [40] is implemented using direct simulation methods. At each

Nonlinear features of the superconductor–ferromagnet–superconductor φ₀ Josephson junction in the ferromagnetic resonance region

• Aliasghar Janalizadeh,
• Ilhom R. Rahmonov,
• Sara A. Abdelmoneim,
• Yury M. Shukrinov and
• Mohammad R. Kolahchi

Beilstein J. Nanotechnol. 2022, 13, 1155–1166, doi:10.3762/bjnano.13.97

• difference with the magnetic moment of a ferromagnet in a φ0 junction leads to a number of unique features important for superconducting spintronics and modern information technology [1][2][3][4][5]. It allows one to control the magnetization precession by the superconducting current and affects the current

• Landau–Lifshitz model to reproduce the damping of the precessing magnetic moment. Gilbert damping is also important in modeling other resonance features, as its temperature dependence affects them [20][21], and, in turn, in the superconducting correlations that affect it [22]. The magnetization

• ferromagnetic resonant frequency (FMR) on the increase of the Gilbert damping was found. We showed that the damped precession of the magnetic moment is dynamically driven by the Josephson supercurrent and the resonance behavior is given by the Duffing spring. The obtained results were based on numerical

A cantilever-based, ultrahigh-vacuum, low-temperature scanning probe instrument for multidimensional scanning force microscopy

• Hao Liu,
• Zuned Ahmed,
• Sasa Vranjkovic,
• Manfred Parschau,
• Andrada-Oana Mandru and
• Hans J. Hug

Beilstein J. Nanotechnol. 2022, 13, 1120–1140, doi:10.3762/bjnano.13.95

• not limited by detector noise at room temperature. Such an extremely high force derivative sensitivity is key for MFM experiments with high spatial resolution (and also to minimize the influence of the tip stray field on the sample by employing low magnetic moment tips). In addition, such a

Controllable two- and three-state magnetization switching in single-layer epitaxial Pd_1−xFe_x films and an epitaxial Pd_0.92Fe_0.08/Ag/Pd_0.96Fe_0.04 heterostructure

• Igor V. Yanilkin,
• Amir I. Gumarov,
• Gulnaz F. Gizzatullina,
• Roman V. Yusupov and
• Lenar R. Tagirov

Beilstein J. Nanotechnol. 2022, 13, 334–343, doi:10.3762/bjnano.13.28

• easy-plane ferromagnets with four-fold anisotropy in the film plane [18][19]. Our conjecture is a possibility to switch the magnetic moment of a Pd1−xFex alloy film between the steady directions (90° apart) as it had been done with epitaxial iron films [20][21][22]. To realize this idea, it is

• magnetic moment by 90° in epitaxial Pd1−xFex films has not been yet explored. In [18][19], based on magnetometry data, it was assumed that magnetization reversal occurs as a result of the coherent rotation of the magnetic moment by 180°; and in the study of the Pd0.96Fe0.04/VN/Pd0.92Fe0.08 structure [23

• resistivity returns to a common value of approx. 15.8 μΩ·cm, corresponding to the magnetic moment along the easy axes (see more details below). The resistivities hierarchy for the magnetic moment oriented along the X-, Y-, and Z-axes, ρx > ρy > ρz, is typical for ferromagnetic films of comparable thickness

Sputtering onto liquids: a critical review

• Anastasiya Sergievskaya,
• Adrien Chauvin and
• Stephanos Konstantinidis

Beilstein J. Nanotechnol. 2022, 13, 10–53, doi:10.3762/bjnano.13.2

Recent progress in magnetic applications for micro- and nanorobots

• Ke Xu,
• Shuang Xu and
• Fanan Wei

Beilstein J. Nanotechnol. 2021, 12, 744–755, doi:10.3762/bjnano.12.58

• -dimensional Helmholtz coil control system was used to form a rotating magnetic field in three dimensions. A change in the direction of the magnetic field exerted a magnetic moment to steer the magnetic structure. Compared with the traditional straight helical structure for MNRs [28], the conical helical

• nanoparticles gain magnetization against an applied external magnetic field. Paramagnetism is caused by spin angular momentum (i.e., spin magnetic moment). Under the action of an external magnetic field, the initially disordered magnetic moments will be reoriented, thereby exhibiting paramagnetism, while other

Free and partially encapsulated manganese ferrite nanoparticles in multiwall carbon nanotubes

• Saja Al-Khabouri,
• Salim Al-Harthi,
• Toru Maekawa,
• Mohamed E. Elzain,
• Ashraf Al-Hinai,
• Ahmed D. Al-Rawas,
• Abbsher M. Gismelseed,
• Ali A. Yousif and
• Myo Tay Zar Myint

Beilstein J. Nanotechnol. 2020, 11, 1891–1904, doi:10.3762/bjnano.11.170

• tetrahedral site increases from 32% to 46%. This may be due to a higher calcination temperature used during the preparation of the partially encapsulated MnFe2O4 sample [20]. The origin of the magnetic hyperfine field in MnFe2O4 is the magnetic moment of the unpaired 3d electrons coupled by a super-exchange

Kondo effects in small-bandgap carbon nanotube quantum dots

• Patryk Florków,
• Damian Krychowski and
• Stanisław Lipiński

Beilstein J. Nanotechnol. 2020, 11, 1873–1890, doi:10.3762/bjnano.11.169

• dots (CNTQDs) is an extended two-orbital Anderson model: where the dot Hamilonian reads: with site dot energies: depending on the magnetic field B∥ and the gate voltage Vg. The upper and lower signs, ±, refer to conduction or valence states, μo is orbital magnetic moment μo = evFD/4, where vF is the

• ) will occur. The corresponding expressions are given below in Equation 9 and Equation 10; here μs = gμB is the spin magnetic moment. SU(4) state occurs for B = 0 and Equations 9–11 are satisfied when Eg > ΔZ and ΔO > ΔZ. The gate dependence of conductance values corresponding to the states in Figure 4

• in all Coulomb valleys. There are also threefold-degeneracy points in a finite field and fourfold-degeneracy points for zero magnetic field. The resonances of the spin SU(2) Kondo effect are characterized by a non-zero orbital moment (quenched spin magnetic moment) and orbital Kondo resonances

Molecular dynamics modeling of the influence forming process parameters on the structure and morphology of a superconducting spin valve

• Alexander Vakhrushev,
• Aleksey Fedotov,
• Vladimir Boian,
• Roman Morari and
• Anatolie Sidorenko

Beilstein J. Nanotechnol. 2020, 11, 1776–1788, doi:10.3762/bjnano.11.160

• ferromagnetic layers causes a restructuring of the magnetic moment configuration under low-power magnetic fields and switches the spin valve from a high to a low resistance state. When a superconducting film is used as a magneto-resistive interlayer, a superconducting spin valve is obtained. Furthermore, these

Proximity effect in [Nb(1.5 nm)/Fe(x)]₁₀/Nb(50 nm) superconductor/ferromagnet heterostructures

• Yury Khaydukov,
• Sabine Pütter,
• Laura Guasco,
• Roman Morari,
• Gideok Kim,
• Thomas Keller,
• Anatolie Sidorenko and
• Bernhard Keimer

Beilstein J. Nanotechnol. 2020, 11, 1254–1263, doi:10.3762/bjnano.11.109

• pattern with coexisting Nb(100) and Nb(110) phases (Figure 3b). Magnetic properties SQUID measurements Figure 4a shows hysteresis loops measured on sample s3 at T = 300 K and T = 13 K. At room temperature the sample saturates to a magnetic moment msat = 12 μemu above a saturation field of only Hsat = 50

• Oe. At 13 K the saturation moment increases to msat = 40 μemu and a field above Hsat ≈ 2 kOe is needed to saturate the magnetic moment of the sample. The temperature dependence of the magnetic moment at H = 250 Oe (Figure 4b) shows that the moment is constant down to T ≈ 100 K, and grows upon further

• cooling to T = 8.2 K. Below this temperature a decrease of the magnetic moment due to the Meissner effect is observed. Polarized neutron reflectometry Figure 5a shows reflectivity curves measured on sample s3 at a temperature of T = 13 K in a magnetic field of H = 4.5 kOe. The curves are characterized by

Influence of the magnetic nanoparticle coating on the magnetic relaxation time

• Mihaela Osaci and
• Matteo Cacciola

Beilstein J. Nanotechnol. 2020, 11, 1207–1216, doi:10.3762/bjnano.11.105

• . Upon reaching the tumour, the magnetic nanoparticles are locally subjected to an alternating magnetic field, generating heat that kills the cancer cells [1]. The heat is generated due to two phenomena: Néel relaxation (an internal phenomenon driven by the rotation of the particle magnetic moment inside

• the particle) and Brown relaxation (an external phenomenon driven by the rotation of the nanoparticle along the magnetic moment). Both internal and external sources of friction lead to a delay in the orientation of the particle magnetic moment in the direction of the applied magnetic field, thus

• particle [25]. The internal dipolar magnetic field is given as where Dij is the distance between the centres of those two nanoparticles, is the versor of the direction connecting the i-th and j-th nanoparticles, μj is the magnetic moment of the j-th nanoparticle ( where Vj is the magnetic core volume of

Epitaxial growth and superconducting properties of thin-film PdFe/VN and VN/PdFe bilayers on MgO(001) substrates

• Wael M. Mohammed,
• Igor V. Yanilkin,
• Amir I. Gumarov,
• Airat G. Kiiamov,
• Roman V. Yusupov and
• Lenar R. Tagirov

Beilstein J. Nanotechnol. 2020, 11, 807–813, doi:10.3762/bjnano.11.65

• . Magnetic moment measurements shown in Figure 4 confirm the composition of Pd0.96Fe0.04 and Pd0.92Fe0.08 through the ferromagnetic transition temperature TC ≈ 125 K and TC ≈ 240 K, respectively [41]. Temperature dependence of resistance and superconducting transition A physical property measurement system

Nonequilibrium Kondo effect in a graphene-coupled quantum dot in the presence of a magnetic field

• Levente Máthé and
• Ioan Grosu

Beilstein J. Nanotechnol. 2020, 11, 225–239, doi:10.3762/bjnano.11.17

• et al. [11] was used to analyze the nonequilibrium Kondo effect in QDs for arbitrary Coulomb interaction [15][16][31] and infinite Coulomb interaction [12][46][48]. The influence of magnetic adatoms on graphene has been studied theoretically [56][57][58][59][60][61][62]. It was found that a magnetic

• moment can be engineered by electrically controlling the properties of a transition metal adatom on graphene providing the possibility to develop graphene-based spintronic devices [56]. Therefore, the physical properties of a graphene monolayer with one of its carbon atoms substituted with a magnetic

Self-assembly of a terbium(III) 1D coordination polymer on mica

• Quentin Evrard,
• Giuseppe Cucinotta,
• Felix Houard,
• Guillaume Calvez,
• Yan Suffren,
• Carole Daiguebonne,
• Olivier Guillou,
• Andrea Caneschi,
• Matteo Mannini and
• Kevin Bernot

Beilstein J. Nanotechnol. 2019, 10, 2440–2448, doi:10.3762/bjnano.10.234

• substrate. Accordingly, the very strong magnetic moment and the high brightness of the TbIII ion facilitate observing the magnetic and the luminescent behavior of [Tb(hfac)3·2H2O]n@mica without any particular surface-dedicated instrumentation. In particular, a significant magnetic signal is observed from

Dynamics of superparamagnetic nanoparticles in viscous liquids in rotating magnetic fields

• Nikolai A. Usov,
• Ruslan A. Rytov and
• Vasiliy A. Bautin

Beilstein J. Nanotechnol. 2019, 10, 2294–2303, doi:10.3762/bjnano.10.221

• assembly of superparamagnetic particles with uniaxial anisotropy distributed in a viscous liquid have been carried out. First, the behavior of a magnetic particle in a RMF is studied in the magneto-dynamics approximation [25][44][45] neglecting the thermal fluctuations of the particle magnetic moment and

• neglect the influence of thermal fluctuations on the behavior of magnetic moment and the particle director and describe their movement in RMFs in the magneto-dynamics approximation [25][44][45]. Without loss of generality one can assume that the magnetic field of constant frequency f and amplitude H0

• in Figure 2 for specific values of Ms, K and η. SAR in RMFs We now turn to the SAR calculation for a dilute assembly of superparamagnetic nanoparticles in RMFs, taking into account thermal fluctuations of the magnetic moment and the director of a superparamagnetic nanoparticle. The SAR calculations

Magnetic properties of biofunctionalized iron oxide nanoparticles as magnetic resonance imaging contrast agents

• Natalia E. Gervits,
• Andrey A. Gippius,
• Alexey V. Tkachev,
• Evgeniy I. Demikhov,
• Sergey S. Starchikov,
• Igor S. Lyubutin,
• Alexander L. Vasiliev,
• Vladimir P. Chekhonin,
• Maxim A. Abakumov,
• Alevtina S. Semkina and
• Alexander G. Mazhuga

Beilstein J. Nanotechnol. 2019, 10, 1964–1972, doi:10.3762/bjnano.10.193

• , respectively. However, small single-domain MNPs with a diameter of less than 10 nm are highly sensitive to thermal energy. Even room temperature is sufficient to destabilize the magnetic moment of the entire nanoparticle and transfer it to a paramagnetic state. The 57Fe Mössbauer spectra of iron oxide

• interaction between the particles is weaker. Therefore, the magnetic moment fluctuates somewhat more for the coated compared to the uncoated particles. This leads to a decrease in the Hmax value, the appearance of a doublet at a lower temperature and a transition to the paramagnetic state at a lower

Giant magnetoresistance ratio in a current-perpendicular-to-plane spin valve based on an inverse Heusler alloy Ti₂NiAl

• Yu Feng,
• Zhou Cui,
• Bo Wu,
• Jianwei Li,
• Hongkuan Yuan and
• Hong Chen

Beilstein J. Nanotechnol. 2019, 10, 1658–1665, doi:10.3762/bjnano.10.161

• ) terminated interfaces. In order to study the magnetic behavior of Ti2NiAl/Ag/Ti2NiAl CPP-SV, we calculated the spin-resolved atom magnetic moment of each layer of the device with various atomic-terminated interfaces, which are shown in Figure 2. It can be seen that the magnetic moment of interfacial Tib

• moments of TiAlT and TiAlB terminated structures are 0.831μB and 0.871μB, respectively. The TiNiT-terminated structure has the highest total interfacial magnetic moment of 1.06μB, while the TiNiB-terminated structure owns the lowest total interfacial magnetic moment of 0.81μB. In addition, when Tia, Tib

• and Ni are in the deep layer of the heterostructure, their magnetic moments are close to the values in Ti2NiAl bulk, indicating that interfacial effects have a minor influence on the magnetic moment of deep-layer atoms. The magnetic property of Al atoms can be explained by the Ruderman–Kittel–Kasuya

Unipolar magnetic field pulses as an advantageous tool for ultrafast operations in superconducting Josephson “atoms”

• Daria V. Popolitova,
• Nikolay V. Klenov,
• Igor I. Soloviev,
• Sergey V. Bakurskiy and
• Olga V. Tikhonova

Beilstein J. Nanotechnol. 2019, 10, 1548–1558, doi:10.3762/bjnano.10.152

• the unperturbed Hamiltonian of the system, is the external magnetic field and stands for the operator of the magnetic moment. In our approach we firstly take into account three energy states of such artificial Josephson atom: two qubit states with energies E1, E2 and one upper-lying level with

• junction phases. (b) A “Not”-operation in a double-well potential of the flux-driven superconducting meta-atom (α = 1.5) is shown as a transition between the states with certain values of the magnetic moment (these states correspond to the energy levels of E1 and E2, respectively). Applied adjusting

The effect of magneto-crystalline anisotropy on the properties of hard and soft magnetic ferrite nanoparticles

• Hajar Jalili,
• Bagher Aslibeiki,
• Ali Ghotbi Varzaneh and
• Volodymyr A. Chernenko

Beilstein J. Nanotechnol. 2019, 10, 1348–1359, doi:10.3762/bjnano.10.133

• and Henkel plots are shown in Figure. 12. The interaction field increases with increasing cobalt content, which can be related to the particle size and the larger magnetic moment of bigger nanoparticles [13][47]. The particle aggregation visible in FE-SEM images shows that the particles are

On the relaxation time of interacting superparamagnetic nanoparticles and implications for magnetic fluid hyperthermia

• Andrei Kuncser,
• Nicusor Iacob and
• Victor E. Kuncser

Beilstein J. Nanotechnol. 2019, 10, 1280–1289, doi:10.3762/bjnano.10.127

• , the link between the two coefficients being expressed as: In the above relation, P/VNP = P* represents the absorbed power per unit volume of MNPs which can be directly related to the evolution of the magnetization (or susceptibility) of the system (magnetic moment per unit volume). For nanoparticles

• perturbation theory due to a mean field effect of the dipolar interactions is to express the magnetic energy of the system by a superposition of uniparticle energies, with the anisotropy energy modified by an additional Zeeman term due to the presence of the particle magnetic moment in the effective field

• –Lifshitz–Gilbert (LLG) equations describing the time evolution of each magnetic moment (only one magnetic moment is assigned to each monodomain-like nanoparticle). For the specific purpose of this work, i.e., the observation of the magnetic behavior under thermal excitations, an extension of the program

Influence of dielectric layer thickness and roughness on topographic effects in magnetic force microscopy

• Alexander Krivcov,
• Jasmin Ehrler,
• Marc Fuhrmann,
• Tanja Junkers and
• Hildegard Möbius

Beilstein J. Nanotechnol. 2019, 10, 1056–1064, doi:10.3762/bjnano.10.106

• magnetic field of the probe with a magnetic moment of 3·10−16 A·m2 is sufficient to induce a magnetic moment at lift heights up to 150 nm in superparamagnetic nanoparticles with 10 nm diameter. This results in attractive forces and, thus, negative phase shifts in MFM measurements. Therefore the magnetic

• magnetized sphere [20][22][23]: where Q is the quality factor of the cantilever, k is the spring constant, µ0 is the vacuum permeability, mp is the magnetic moment of the nanoparticle, mtip is the magnetic moment of the tip, and a is the distance between the two dipoles and is shown schematically in Figure 5

• and SPION. Figure 7 shows the phase shift as a function of lift height for substrates with different dielectric layer thicknesses ranging from 0 nm (no layer) up to 380 nm. The measurements are carried out with a tip with high magnetic moment (ASYMFM-HM tip) in order to obtain a strong magnetic

Electronic and magnetic properties of doped black phosphorene with concentration dependence

• Ke Wang,
• Hai Wang,
• Min Zhang,
• Yan Liu and
• Wei Zhao

Beilstein J. Nanotechnol. 2019, 10, 993–1001, doi:10.3762/bjnano.10.100

• for the Si-doped phosphorene with 2 × 2 × 1 supercell and a dopant content of 6.25%. The magnetic moment induced by 3p orbit–spin splitting increases with the in-plane size of the supercell, and the largest magnetic moment can be found in 4 × 4 × 1 and 5 × 5 × 1 supercells. These findings offer an

• . According to the first-principles calculations, we find that the magnetic moment of doped phosphorene increases significantly with increasing the in-plane size of the supercell and reducing the impurity concentration, while the bandgap of doped phosphorene is opened due to the shrinking of the charge

• magnetic moment In order to identify the magnetism of Si- and S-doped phosphorenes, the energy difference ΔEsp was calculated as follows [24][25][26]: where Esp and Ensp are the energy of doped phosphorene computed with spin polarization and without polarization, respectively. According to the lowest

Magnetic field-assisted assembly of iron oxide mesocrystals: a matter of nanoparticle shape and magnetic anisotropy

• Julian J. Brunner,
• Marina Krumova,
• Helmut Cölfen and
• Elena V. Sturm (née Rosseeva)

Beilstein J. Nanotechnol. 2019, 10, 894–900, doi:10.3762/bjnano.10.90

• driven by competing of two types of anisotropic interactions caused by particle shape (i.e., faceting) and orientation of the magnetic moment (i.e., easy axes: <111>magnetite). Hence, these findings provide a fundamental understanding of formation mechanisms and structuring of mesocrystals built up from

• ]. Due to the superparamagnetic property of the magnetite nanocrystals, their assembly process can be strongly influenced by an external magnetic field which is then labelled as “directed assembly” [21]. The magnetic moment of the magnetic nanocrystals tends to align along a certain crystallographic axis

• shape (i.e., faceting), while the alignment along the magnetic field lines is driven by the orientation of the magnetic moment of the nanoparticles (i.e., easy axis: <111>magnetite). Future work applying varying magnetic field strength will show the structural variety of the mesocrystals, which is