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

• of magnetic anisotropy, the direction of the particle easy anisotropy axes, and other parameters. In addition, the FMR spectrum is sensitive to the presence of magnetostatic interactions in dense assemblies of magnetic nanoparticles. Thus, ferromagnetic resonance spectroscopy is a promising technique

• field H. In this paper the calculation of the specific absorbed power is carried out using Equation 8 for dilute assemblies of linear chains of magnetosomes with saturation magnetization Ms = 460 emu/cm3 and cubic magnetic anisotropy constant Kc = −1.1 × 105 erg/cm3 [37]. The average diameter 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

• nanoparticles with uniaxial magnetic anisotropy randomly oriented in a solid matrix. The saturation magnetization of particles and the magnetic anisotropy constant are taken to be Ms = 350 emu/cm3 and K1 = 105 erg/cm3, respectively [27]. The range of nanoparticle diameters studied is D = 18–50 nm, the

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

• -hand side are the Zeeman and exchange interactions, respectively, the next two terms describe magnetic anisotropy, followed by the terms responsible for the Dzialoshinsky–Moriya, magnetoelectric, and dipole interactions, respectively. The consideration of different types of interactions in a model

• the crystal lattice of magnets largely determine the type and shape of the resulting magnetic anisotropy. In ferromagnets, magnetic anisotropy is characterized by the magnitude and orientation of the magnetization, as well as by the change in the magnetic energy of the material. The main causes of

• magnetic anisotropy are temperature changes, dipole interactions, mechanical deformations, or other external factors. If external influences are absent, then due to spin–orbit interactions of atoms inside the nanomaterial, magnetic crystallographic anisotropy can occur, which is caused by a change in the

A new method for obtaining the magnetic shape anisotropy directly from electron tomography images

• Cristian Radu,
• Ioana D. Vlaicu and
• Andrei C. Kuncser

Beilstein J. Nanotechnol. 2022, 13, 590–598, doi:10.3762/bjnano.13.51

• rare earth-free permanent magnets [16][17], a more complex description of the morphology including particle shape and specific aspect ratio, as the main factors influencing the magnetic anisotropy [18][19] is absolutely necessary. The new methodology that is proposed here, implemented in Magn3t, is

Topographic signatures and manipulations of Fe atoms, CO molecules and NaCl islands on superconducting Pb(111)

• Carl Drechsel,
• Philipp D’Astolfo,
• Jung-Ching Liu,
• Thilo Glatzel,
• Rémy Pawlak and
• Ernst Meyer

Beilstein J. Nanotechnol. 2022, 13, 1–9, doi:10.3762/bjnano.13.1

• possibility to tune the magnetic anisotropy of a single porphyrin molecule by perturbing its ligand field with the STM probe [39][40]. These results not only suggest the importance of future manipulations experiments, but also shed new lights into the potential of decoupling atoms and molecules electronically

Heating ability of elongated magnetic nanoparticles

• Elizaveta M. Gubanova,
• Nikolai A. Usov and
• Vladimir A. Oleinikov

Beilstein J. Nanotechnol. 2021, 12, 1404–1412, doi:10.3762/bjnano.12.104

• also examined. Theoretical studies [18][19][20][21][22][23][24][25][26] show that to achieve high SAR values several important factors have to be taken into account, such as the geometric dimensions of particles, particle saturation magnetization, magnitude of the magnetic anisotropy constant, and

• is assumed for simplicity that single-domain magnetite nanoparticles are monocrystalline, so that the cubic-type magneto-crystalline anisotropy energy of the assembly is given by [25]: Here, Kc = −105 erg/cm3 is the cubic magnetic anisotropy constant [47], V = πab2/6 is the volume of a spheroidal

• nanoparticles with saturation magnetization Ms = 350 emu/cm3 depending on the value of the effective uniaxial magnetic anisotropy constant in the range Ku = 1 × 104–5 × 105 erg/cm3. This fact shows once again that the dependence of the SAR of a dilute assembly of magnetite nanoparticles on the aspect ratio is

Biocompatibility and cytotoxicity in vitro of surface-functionalized drug-loaded spinel ferrite nanoparticles

• Sadaf Mushtaq,
• Khuram Shahzad,
• Tariq Saeed,
• Anwar Ul-Hamid,
• Bilal Haider Abbasi,
• Nafees Ahmad,
• Waqas Khalid,
• Muhammad Atif,
• Zulqurnain Ali and
• Rashda Abbasi

Beilstein J. Nanotechnol. 2021, 12, 1339–1364, doi:10.3762/bjnano.12.99

• ) values, as shown in Table 3 [24]. From Figure 2c, all samples went through saturation at an applied field of 2.0 T, except nickel ferrite. This is may be due to the presence of a strong magnetic anisotropy, which required a higher applied field to induce saturation [25]. Cobalt ferrite has the maximum

• coercivity (883 Oe) and saturation magnetization values (56 emu/g) in comparison to other ferrites due to a high anisotropy. Also, during cationic distribution, Co+2 cations incorporate into Fe–O, whereas the cationic distribution of other divalent metals (e.g., Ni+2 or Zn+2) leads to a decrease in magnetic

• anisotropy [17][26]. Moreover, zinc ferrite has a slightly increased coercivity than nickel ferrite and iron oxide due to the formation of a noncollinear ferrimagnetic structure [27]. From Table 3, cobalt ferrite has the best magnetic properties in terms of saturation magnetization and coercivity, followed

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

• SiO2/Si substrate were irradiated on one half with 25 keV helium ions. It was found that at a dose of 2 × 1015 ions/cm2 a domain wall could be injected into the structure due to the introduction of lattice defects that locally reduced the perpendicular magnetic anisotropy. By raising the dose slightly

• resolution capability of the helium ion beam enabling the creation of a sharper energy barrier at the domain wall. Later work in this area employed similar helium ion doses (1–4 × 1015 ions/cm2) to locally reduce the perpendicular magnetic anisotropy in a Co/Pt multilayered thin film [50]. Here, patterns

• and the underlying substrate on the magnetic modification obtained. It was found that helium ion bombardment influenced the magnetic anisotropy in both layers of the structure, strongly reducing the saturation magnetization of the layer system. Moreover, the behavior observed correlated with both the

The patterning toolbox FIB-o-mat: Exploiting the full potential of focused helium ions for nanofabrication

• Victor Deinhart,
• Lisa-Marie Kern,
• Jan N. Kirchhof,
• Sabrina Juergensen,
• Joris Sturm,
• Enno Krauss,
• Thorsten Feichtner,
• Sviatoslav Kovalchuk,
• Michael Schneider,
• Dieter Engel,
• Bastian Pfau,
• Bert Hecht,
• Kirill I. Bolotin,
• Stephanie Reich and
• Katja Höflich

Beilstein J. Nanotechnol. 2021, 12, 304–318, doi:10.3762/bjnano.12.25

• , atomic composition, and crystallographic phase [33][34]. Here, the impact of He irradiation on the ferromagnetic multilayer [Co0.6/Pt0.8]15 is studied [35][36]. This multilayer shows perpendicular magnetic anisotropy arising from the Co/Pt interfaces and forms nanometer-scale, labyrinth-like domains with

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

• corresponding magnetic configuration of the system. For the numerical simulation, two widely known models have been used [19][20][21]. We started with a system of single-domain magnetic nanoparticles, consisting of spherical iron-oxide nanoparticles with uniaxial magnetic anisotropy, which have a lognormal

• Equation 9, θi is the angle between the easy magnetisation and anisotropy axes of the i-th nanoparticle; therefore: In Equation 18 and Equation 20, is the effective magnetic anisotropy constant of the i-th nanoparticle. If hi < hic(Ψi) < 1 [21][22], then Simulation conditions and results For this study

Applications of superparamagnetic iron oxide nanoparticles in drug and therapeutic delivery, and biotechnological advancements

• Maria Suciu,
• Corina M. Ionescu,
• Alexandra Ciorita,
• Septimiu C. Tripon,
• Dragos Nica,
• Hani Al-Salami and
• Lucian Barbu-Tudoran

Beilstein J. Nanotechnol. 2020, 11, 1092–1109, doi:10.3762/bjnano.11.94

• , size, volume, magnetic anisotropy, concentration, and the potential to remain dispersed and not to agglomerate at the site of action [63]. Hyperthermia only works if the nanoparticles have a single magnetic domain, i.e., if they behave uniformly throughout the entire mass as a single magnet. There are

Observation of unexpected uniaxial magnetic anisotropy in La_2/3Sr_1/3MnO₃ films by a BaTiO₃ overlayer in an artificial multiferroic bilayer

• John E. Ordóñez,
• Lorena Marín,
• Luis A. Rodríguez,
• Pedro A. Algarabel,
• José A. Pardo,
• Roger Guzmán,
• Luis Morellón,
• César Magén,
• Etienne Snoeck,
• María E. Gómez and
• Manuel R. Ibarra

Beilstein J. Nanotechnol. 2020, 11, 651–661, doi:10.3762/bjnano.11.51

• results indicate that the BaTiO3 layer induces an additional strain in the La2/3Sr1/3MnO3 layers close to their common interface. The presence of BaTiO3 on the surface of tensile-strained La2/3Sr1/3MnO3 films transforms the in-plane biaxial magnetic anisotropy present in the single layer into an in-plane

• uniaxial magnetic anisotropy. Our experimental evidence suggests that this change in the magnetic anisotropy only occurs in tensile-strained La2/3Sr1/3MnO3 film and is favored by an additional strain on the La2/3Sr1/3MnO3 layer promoted by the BaTiO3 film. These findings reveal an additional mechanism that

• ; magnetic anisotropy; Introduction In recent years, enormous interest has been shown in the multiferroic properties of the multilayered system based on La2/3Sr1/3MnO3 (LSMO) and BaTiO3 (BTO) films [1][2][3][4][5]. Each perovskite material has a particular ferroic order at room temperature, i.e

Formation of nanoripples on ZnO flat substrates and nanorods by gas cluster ion bombardment

• Xiaomei Zeng,
• Vasiliy Pelenovich,
• Bin Xing,
• Rakhim Rakhimov,
• Wenbin Zuo,
• Alexander Tolstogouzov,
• Chuansheng Liu,
• Dejun Fu and
• Xiangheng Xiao

Beilstein J. Nanotechnol. 2020, 11, 383–390, doi:10.3762/bjnano.11.29

• -enhanced Raman spectroscopy [4]. Ion beam formation of nanoscale ripples has emerged as a versatile method to imprint uniaxial magnetic anisotropy [5] and to control the magnetic texture of thin films [6]. Formation of self-assembled surface nanoripple structures by monoatomic off-normal ion irradiation

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

• -surface properties [11][12]. The terbium(III) ion, (TbIII), is a particularly suitable candidate for the creation of surface-based magnetic and luminescent devices [5][6]. It has one of the highest magnetic moments of all elements in the periodic table, and it shows a very strong magnetic anisotropy when

• spin carrier. However, a full saturation of the magnetization is not observed at 40 kOe, probably because of a partial loss of the magnetic anisotropy of TbIII in the deposits (vide infra). Dynamic magnetic measurements have also been performed (Figure 5). In these measurements, the magnetic

• sample is similar to that of crystalline bulk [Tb(hfac)3·2H2O]n. Namely, two maxima of X″ are observed, which however differently depend on the static magnetic field applied (Figure S3 and Figure S4, Supporting Information File 1) probably due to a partial loss of the magnetic anisotropy of TbIII upon

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

• the effective magnetic anisotropy constant of the nanoparticle, Hk = 2K/Ms is the particle anisotropy field, and Ms is the saturation magnetization. Equations 1–3 describe the complex coupled dynamics of the unit vectors and in RMFs. Numerical solution of Equations 1–3 with a small time step

• a saturation magnetization Ms = 350 emu/cm3 and a magnetic anisotropy constant K = 105 erg/cm3. The liquid viscosity is assumed to be η = 0.01 g/(cm·s). The domains of existence of various magneto-dynamic regimes I–III on the plane (f, H0) determined numerically using the abovementioned physical

• of a dilute assembly of superparamagnetic nanoparticles distributed in a viscous fluid in RMFs and AMFs. In the calculations presented in Figure 4 the saturation magnetization of nanoparticles is given by Ms = 350 emu/cm3, the effective magnetic anisotropy constant K = 105 erg/cm3, the particle

Oblique angle deposition of nickel thin films by high-power impulse magnetron sputtering

• Hamidreza Hajihoseini,
• Movaffaq Kateb,
• Snorri Þorgeir Ingvarsson and
• Jon Tomas Gudmundsson

Beilstein J. Nanotechnol. 2019, 10, 1914–1921, doi:10.3762/bjnano.10.186

• at small tilt angles while larger tilt angles result in uniaxial magnetic anisotropy. The transition tilt angle varies with deposition method and is measured around 35° for dcMS and 60° for HiPIMS. Conclusion: Due to the high discharge current and high ionized flux fraction, the HiPIMS process can

• sputtering; magnetic anisotropy; nickel; Introduction The realization of electronics based on utilizing the electron spin degree of freedom, commonly referred to as spintronics, requires the integration of ferromagnetic films with semiconductors [1]. Nickel is a ferromagnetic heavy 3d transition metal that

• ° tilt using dcMS and HiPIMS. The films prepared by HiPIMS present a lower anisotropy field (Hk) and coercivity (Hc) than films deposited with dcMS. For the polycrystalline films both deposition methods give uniaxial magnetic anisotropy due to the oblique deposition. However, for the epitaxial films dcMS

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

• collective magnetic behavior. Studies show that the magnetic properties are strongly affected by the magnetic anisotropy of NPs and by interparticle interactions that are the result of the collective magnetic behavior of NPs. Here we study these effects in more detail. For this purpose, we prepared CoxFe3

• −xO4 NPs, with x = 0–1 in steps of 0.2, from soft magnetic (Fe3O4) to hard magnetic (CoFe2O4) ferrite, with a significant variation of the magnetic anisotropy. The phase purity and the formation of crystalline NPs with a spinel structure were confirmed through Rietveld refinement. The effect of Co

• [1][2]. In recent years, ferrite nanoparticles with the general formula of MFe2O4 (M = Fe, Co, Ni, Mn) have attracted great attention of researchers due to their potential applications in biomedicine and industry [3]. Magnetic anisotropy and interparticle interactions are important parameters that

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

• of thirteen magnetic nanoparticles (each of size 4.4 × 4 × 4 nm in order to assure the uniaxial magnetic anisotropy) with no magneto-crystalline anisotropy, a stiffness constant (A) of 1.3 × 10−11 J/m3 and a spontaneous magnetization (Ms) of 8.5 × 105 A/m have been arranged in a bidimensional

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

• -to-face alignment (i.e., interaction of the particle {110} faces with other particle faces within the layer) and on the other side magnetic anisotropy of magnetite nanoparticles induces the alignment of the <111>magnetite easy axis parallel to the direction of the external magnetic field

Co-doped MnFe₂O₄ nanoparticles: magnetic anisotropy and interparticle interactions

• Bagher Aslibeiki,
• Parviz Kameli,
• Hadi Salamati,
• Giorgio Concas,
• Maria Salvador Fernandez,
• Alessandro Talone,
• Giuseppe Muscas and
• Davide Peddis

Beilstein J. Nanotechnol. 2019, 10, 856–865, doi:10.3762/bjnano.10.86

• , the effect of the chemical composition, i.e., the amount of Co doping, produces marked differences on the magnetic properties, especially on the magnetic anisotropy, with evident large changes in the coercive field. Moreover, Co substitution has a profound effect on the interparticle interactions, too

• , hence showing a final net magnetization (ferrimagnetism) which depends directly on the specific population of Td and Oh sites. Furthermore, the magnetic anisotropy of the system is related to the specific cationic population and distribution in the different interstitial sites [19]. In the present paper

• of Co substitution on the magnetic properties of the whole ensemble. The Co substitution does not only affect the single particle anisotropy energy, and thus the intrinsic magnetic anisotropy of individual particles, but also the overall interacting regime among them. Because the samples are dense

Heating ability of magnetic nanoparticles with cubic and combined anisotropy

• Nikolai A. Usov,
• Mikhail S. Nesmeyanov,
• Elizaveta M. Gubanova and
• Natalia B. Epshtein

Beilstein J. Nanotechnol. 2019, 10, 305–314, doi:10.3762/bjnano.10.29

• magnetic anisotropy have mostly been studied. Meanwhile, perfect iron oxide nanoparticles of spherical shape should have cubic-type magnetic anisotropy [5]. However, to describe the existing experimental data properly one has also to take into account the possible perturbation of the nanoparticle shape. A

• appreciable contribution to the total particle energy. As a result, the nanoparticles having shape perturbation possess combined magnetic anisotropy [23]. In this paper the low frequency hysteresis loops and the SAR of magnetite nanoparticles with cubic and combined magnetic anisotropy have been calculated

• interacting nanoparticles. It is also important for clusters of magnetite nanoparticles with cubic and combined magnetic anisotropy that the maximal SAR values shift to larger particle diameters with respect to those for similar nanoparticles with uniaxial anisotropy [22]. This is attributed to a decreased

Relation between thickness, crystallite size and magnetoresistance of nanostructured La_1−xSr_xMn_yO_3±δ films for magnetic field sensors

• Rasuole Lukose,
• Valentina Plausinaitiene,
• Milita Vagner,
• Nerija Zurauskiene,
• Skirmantas Kersulis,
• Virgaudas Kubilius,
• Karolis Motiejuitis,
• Birute Knasiene,
• Voitech Stankevic,
• Zita Saltyte,
• Martynas Skapas,
• Algirdas Selskis and
• Evaldas Naujalis

Beilstein J. Nanotechnol. 2019, 10, 256–261, doi:10.3762/bjnano.10.24

• practical applications due to low sensitivity and large magnetic anisotropy [15][16]. For this reason, the investigation and control of the magnetoresistive properties of manganite materials on the nanometer scale is of great importance. It was shown that the change of nanostructure by variation of

Size limits of magnetic-domain engineering in continuous in-plane exchange-bias prototype films

• Alexander Gaul,
• Daniel Emmrich,
• Timo Ueltzhöffer,
• Henning Huckfeldt,
• Hatice Doğanay,
• Johanna Hackl,
• Muhammad Imtiaz Khan,
• Daniel M. Gottlob,
• Gregor Hartmann,
• André Beyer,
• Dennis Holzinger,
• Slavomír Nemšák,
• Claus M. Schneider,
• Armin Gölzhäuser,
• Günter Reiss and
• Arno Ehresmann

Beilstein J. Nanotechnol. 2018, 9, 2968–2979, doi:10.3762/bjnano.9.276

• charge density in the domain wall center, causing a widening of the latter [44]. The DW spreads wider into the bombarded areas than into the non-bombarded areas, resulting in asymmetric DWs. This is caused by the reduced effective magnetic anisotropy within the bombarded regions correlated to the nuclear

• saturation magnetization [35] and the uniaxial magnetic anisotropy constant [40] are Dtail,B = 1.32 μm for the bombarded and Dtail,NB = 1.04 μm for the non-bombarded regions (see Appendix for details), it is evident that for b ≤ 2 μm there is a significant crosstalk between neighboring DWs. However, the

• were carried out using the object-oriented micromagnetic framework (OOMMF) for a 10 nm thick Co70Fe30 film assuming a uniaxial magnetic anisotropy constant of KF,NB = 4.5 × 104 J·m−3 for the non-bombarded areas [43] and KF,B = 0.71KF,NB for the bombarded areas [40]. The saturation magnetization in the

Magnetic and luminescent coordination networks based on imidazolium salts and lanthanides for sensitive ratiometric thermometry

• Pierre Farger,
• Cédric Leuvrey,
• Mathieu Gallart,
• Pierre Gilliot,
• Guillaume Rogez,
• João Rocha,
• Duarte Ananias,
• Pierre Rabu and
• Emilie Delahaye

Beilstein J. Nanotechnol. 2018, 9, 2775–2787, doi:10.3762/bjnano.9.259

• networks, the luminescent properties can be used to synthesize temperature probes with possible applications in the aerospace area, safety and health [17][18]. Beside luminescent properties, lanthanide ions exhibit large magnetic moment and strong magnetic anisotropy, which might have potential

Size-selected Fe₃O₄–Au hybrid nanoparticles for improved magnetism-based theranostics

• Maria V. Efremova,
• Yulia A. Nalench,
• Eirini Myrovali,
• Anastasiia S. Garanina,
• Ivan S. Grebennikov,
• Polina K. Gifer,
• Maxim A. Abakumov,
• Marina Spasova,
• Makis Angelakeris,
• Alexander G. Savchenko,
• Michael Farle,
• Natalia L. Klyachko,
• Alexander G. Majouga and
• Ulf Wiedwald

Beilstein J. Nanotechnol. 2018, 9, 2684–2699, doi:10.3762/bjnano.9.251

• (Table 2). The temperature dependence of the coercive field HC(T) allows us to estimate the effective magnetic anisotropy energy density Keff (Table 3) by using Sharrock’s equation for single domain, randomly oriented, non-interacting NPs [47][48][49]: Random orientation and single domain properties are

• the NPs, especially significant for the present octahedra, increase the effective magnetic anisotropy by shape anisotropy which increases quadratically with MS [59]. Experimentally, this was observed by Joshi et al. [74] and Smolensky et al. [75] when they compared spherical and faceted NPs. In both

• determined by XRD and AES analysis. Overview of the size-dependent magnetic properties of Fe3O4–Au NPs. Saturation magnetization MS at 9 T, T = 5 K and T = 300 K, coercive field µ0HC at T = 5 K, and deduced blocking temperature, TB, and effective magnetic anisotropy, Keff. The bulk Fe3O4 reference values are