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

• anisotropy in cobalt were used in [43]. The model proposed by Neel considers magnetocrystalline anisotropy in more complex forms as compared to uniaxial anisotropy. This model is used to describe magnetocrystalline anisotropy between pairs of magnetic spins: where the intensity of the dipole and quadrupole

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

• magnetocrystalline anisotropy, high saturation magnetization, and coercivity even at room temperature as compared to others [15]. The substitution of metal cations M+ for cobalt, nickel, and zinc contributes to diverse magnetic properties, morphology, and size of iron oxide NPs [13][16] along with varied tissue

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

• compared to that in free MnFe2O4 nanoparticles. This leads to an enhancement of the magnetocrystalline anisotropy constant of partially encapsulated MnFe2O4, which in turn leads to the enhancement of coercivity [20]. Geng et al. [45] fabricated Fe-filled CNT arrays with high coercivity, which is primarily

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

• magnetocrystalline anisotropy at room temperature [10]. The anisotropy constant of CoFe2O4 (K = 2 × 105 J·m−3) is nearly one order of magnitude larger than that of Fe3O4 [11][12][13]. Fe3O4 NPs have been studied extensively for bio-medical applications, such as drug delivery [14], magnetic resonance imaging (MRI

• the anisotropy for x > 0.6 in CoxFe3−xO4 nanoparticles. They attributed this effect to Co–Co interactions at high Co concentrations leading to a reduction of anisotropy, while Fe–Co interactions in the lattice increase the magnetocrystalline anisotropy. Figure 10 shows Hc as a function of the cobalt

Tailoring the magnetic properties of cobalt ferrite nanoparticles using the polyol process

• Malek Bibani,
• Romain Breitwieser,
• Alex Aubert,
• Vincent Loyau,
• Silvana Mercone,
• Souad Ammar and
• Fayna Mammeri

Beilstein J. Nanotechnol. 2019, 10, 1166–1176, doi:10.3762/bjnano.10.116

• while the sub-stoichiometric NPs (particularly for x ≈ 0.7) are expected to be less magnetostrictive but to present a higher magnetocrystalline anisotropy constant, as previously observed in bulk cobalt ferrites. To control the size of the NPs, in order to overcome the superparamagnetic limit, as well

• piezoelectric polymers. Keywords: cobalt ferrite; magnetocrystalline anisotropy; magnetostriction; nanoparticle; non-stoichiometry; polyol process; Introduction Recently, extrinsically (or artificially) magnetoelectric (ME) multiferroic (MF) materials have been seriously investigated for many applications in

• magnetostrictive properties of the two most interesting samples, i.e., Co0.67Fe2.33O4, known to exhibit the highest magnetocrystalline anisotropy (Co-0.67-TriEG-6), and CoFe2O4, known to present the highest magnetostriction (Co-1-TetEG-6). XRD patterns of all the produced CoxFe3−xO4 powders. X-ray fluorescence

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

• , the influence of the demagnetization field leads to the formation of a local, almost flux-closure-like pattern of the magnetic moment distribution. This can be also seen in the simulations particularly for the smaller domains, since there the contribution of the magnetocrystalline anisotropy energy is

Magnetism and magnetoresistance of single Ni–Cu alloy nanowires

• Andreea Costas,
• Camelia Florica,
• Elena Matei,
• Maria Eugenia Toimil-Molares,
• Ionel Stavarache,
• Andrei Kuncser,
• Victor Kuncser and
• Ionut Enculescu

Beilstein J. Nanotechnol. 2018, 9, 2345–2355, doi:10.3762/bjnano.9.219

• constant (the magnetocrystalline anisotropy constant of the material is proven to be less relevant in structures where the shape anisotropy is dominant). To provide realistic values for MS under similar conditions to the magnetoresistance measurements, hysteresis loops at 300 K were collected by SQUID

Cubic chemically ordered FeRh and FeCo nanomagnets prepared by mass-selected low-energy cluster-beam deposition: a comparative study

• Veronique Dupuis,
• Anthony Robert,
• Arnaud Hillion,
• Ghassan Khadra,
• Nils Blanc,
• Damien Le Roy,
• Florent Tournus,
• Clement Albin,
• Olivier Boisron and
• Alexandre Tamion

Beilstein J. Nanotechnol. 2016, 7, 1850–1860, doi:10.3762/bjnano.7.177

• transition between FM to bulk-like AFM order. On the other hand, even if some theoretical papers [35] predict that bulk FeCo alloys doped by carbon can lead to an enhanced magnetocrystalline anisotropy energy of up to 0.75 MJ/m3 by conserving 70% of the FeCo average magnetic moment per atom, we have shown

Orientation of FePt nanoparticles on top of a-SiO₂/Si(001), MgO(001) and sapphire(0001): effect of thermal treatments and influence of substrate and particle size

• Martin Schilling,
• Paul Ziemann,
• Zaoli Zhang,
• Johannes Biskupek,
• Ute Kaiser and
• Ulf Wiedwald

Beilstein J. Nanotechnol. 2016, 7, 591–604, doi:10.3762/bjnano.7.52

• transmission electron microscopy (HRTEM); nanoparticles; reflection high-energy electron diffraction (RHEED); solid-phase epitaxy; texture; Introduction Due to their attractive catalytic properties for oxygen reduction reactions (ORR) [1][2] as well as their high magnetocrystalline anisotropy energy density

Structural and magnetic properties of iron nanowires and iron nanoparticles fabricated through a reduction reaction

• Marcin Krajewski,
• Wei Syuan Lin,
• Hong Ming Lin,
• Katarzyna Brzozka,
• Sabina Lewinska,
• Natalia Nedelko,
• Anna Slawska-Waniewska,
• Jolanta Borysiuk and
• Dariusz Wasik

Beilstein J. Nanotechnol. 2015, 6, 1652–1660, doi:10.3762/bjnano.6.167

• identical, this observation is surprising at the first moment. In general, the effective anisotropy of the nanowires should be much higher due to the high uniaxial shape anisotropy, which is increased by the magnetocrystalline anisotropy with the easy axis oriented along the wire length caused by the

Influence of the shape and surface oxidation in the magnetization reversal of thin iron nanowires grown by focused electron beam induced deposition

• Luis A. Rodríguez,
• Lorenz Deen,
• Rosa Córdoba,
• César Magén,
• Etienne Snoeck,
• Bert Koopmans and
• José M. De Teresa

Beilstein J. Nanotechnol. 2015, 6, 1319–1331, doi:10.3762/bjnano.6.136

• magnetocrystalline anisotropy effects and, as a consequence, shape anisotropy will determine the magnetic anisotropy of the wires. The Fe content determined by EELS inside the wires is around 85%, in good agreement with the EDS performed inside the FIB-SEM equipment. According to previous studies, the saturation

• = 0 (we assume that in nanocrystalline iron the magnetocrystalline anisotropy is averaged out). For the simulation, we have adopted the same in-plane geometry used for the MOKE measurements shown before. In order to decrease the simulation time, different cell sizes have been used depending on the

Magnetic properties of iron cluster/chromium matrix nanocomposites

• Arne Fischer,
• Robert Kruk,
• Di Wang and
• Horst Hahn

Beilstein J. Nanotechnol. 2015, 6, 1158–1163, doi:10.3762/bjnano.6.117

• almost two orders of magnitude bigger than one would expect for clusters with the magnetocrystalline anisotropy of bulk α-iron. Both results lead to the conclusion that for the lowest concentration of clusters the effective anisotropy constant is determined by magnetic exchange interactions with the Cr

Tunable magnetism on the lateral mesoscale by post-processing of Co/Pt heterostructures

• Oleksandr V. Dobrovolskiy,
• Maksym Kompaniiets,
• Roland Sachser,
• Fabrizio Porrati,
• Christian Gspan,
• Harald Plank and
• Michael Huth

Beilstein J. Nanotechnol. 2015, 6, 1082–1090, doi:10.3762/bjnano.6.109

• carbon. Thus, in the course of the reaction, carbon is partially removed from the deposit causing a reduction of the deposit thickness. The magnetic behavior of the thin polycrystalline Co stripe A is dominated not by the magnetocrystalline anisotropy, but rather by the shape anisotropy causing the

• explained by the increasing perpendicular magnetocrystalline anisotropy. The Hall voltage cycling U(H) for sample D was repeated at different temperatures up to room temperature, see Figure 8. The temperature-induced reduction of the coercive field and the remanent magnetization is presented in the inset to

Cathode lens spectromicroscopy: methodology and applications

• T. O. Menteş,
• G. Zamborlini,
• A. Sala and
• A. Locatelli

Beilstein J. Nanotechnol. 2014, 5, 1873–1886, doi:10.3762/bjnano.5.198

• map in Figure 10b (right panel). This is a surprising confirmation of the magnetocrystalline anisotropy strength dominating the shape anisotropy. Iron oxides find wide application in several fields of research, among others magnetism and heterogeneous catalysis. In both cases, the heteroepitaxial

Hydrogen-plasma-induced magnetocrystalline anisotropy ordering in self-assembled magnetic nanoparticle monolayers

• Alexander Weddemann,
• Judith Meyer,
• Anna Regtmeier,
• Irina Janzen,
• Dieter Akemeier and
• Andreas Hütten

Beilstein J. Nanotechnol. 2013, 4, 164–172, doi:10.3762/bjnano.4.16

• ; magnetocrystalline anisotropy; monolayers; Introduction Due to their wide range of applications in physical, biological and medical fields, magnetic nanoparticles have been thoroughly studied during the past few decades [1][2]. In this regard, various manufacturing techniques to synthesize particles with distinct

• prerequisite for such an application is the high thermal stability of a magnetic state in order to maintain the magnetic configuration and not to lose the stored information. In the case of a single particle, materials with a strong uniaxial magnetocrystalline anisotropy, such as face-centered tetragonal L10

• components are aligned parallel to the magnetization directions of the magnetic equilibrium state of the system itself. If particles with low magnetocrystalline anisotropy are considered, the magnetic equilibrium state is mainly dominated by dipolar coupling. In this case, the magnetic-moment vectors do not

Nanoscaled alloy formation from self-assembled elemental Co nanoparticles on top of Pt films

• Luyang Han,
• Ulf Wiedwald,
• Johannes Biskupek,
• Kai Fauth,
• Ute Kaiser and
• Paul Ziemann

Beilstein J. Nanotechnol. 2011, 2, 473–485, doi:10.3762/bjnano.2.51

• ordered arrays of Co NPs on top of textured and epitaxial Pt films. Similarly to the previous research interest in FePt equiatomic alloys in the chemically ordered L10 phase, our interest in this system is motivated by the magnetic properties of CoPt alloys exhibiting very large magnetocrystalline

• anisotropy energy density (MAE) and, directly related to that, a high value of the coercive field HC in the direction of the easy axis of magnetization. However, as it has been reported previously, laterally extended CoPt alloy systems may form CoPt3 as well [14]. At this composition the MAE is significantly

• ) derives its sensitivity from being both element specific and surface sensitive. It is therefore ideally suited for the kind of specimens studied here. In addition to the information contained in (both, SQUID and XMCD) hysteresis loops, we obtain spectroscopic signatures of the average magnetocrystalline

Structural and magnetic properties of ternary Fe_1–xMn_xPt nanoalloys from first principles

• Markus E. Gruner and
• Peter Entel

Beilstein J. Nanotechnol. 2011, 2, 162–172, doi:10.3762/bjnano.2.20

• as small as 3 nm if the bulk values of the anisotropy constant are assumed. Both materials owe their large magnetocrystalline anisotropy to the strong hybridization of the electronic states of the 3d and 5d elements [19]. In addition, the L10 order, which is defined by a layer-wise alternating

• been discovered that L10 particles with a sufficient magnetocrystalline anisotropy are difficult to obtain in the corresponding size range [16][20][21][22][23]. It is certainly a straight-forward idea to seek the problem in the lower dimensionality of the particles. These naturally contain a

• morphologies consist of several strained twins – twenty in the case of Mackay icosahedra and five in the case of decahedra. Although the twins may be perfectly L10 ordered, they will not exhibit a significant uniaxial magnetocrystalline anisotropy because of the different crystallographic orientations of the

Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles

• Ulf Wiedwald,
• Luyang Han,
• Johannes Biskupek,
• Ute Kaiser and
• Paul Ziemann

Beilstein J. Nanotechnol. 2010, 1, 24–47, doi:10.3762/bjnano.1.5

• for systems which undergo a phase transition and thereby improves their magnetic properties such as in the cases of FePt or CoPt NPs which are of technological interest due to their high magnetocrystalline anisotropy in the L10 phase. However, it has mostly been observed that the as-prepared particles

Preparation, properties and applications of magnetic nanoparticles

• Ulf Wiedwald and
• Paul Ziemann

Beilstein J. Nanotechnol. 2010, 1, 21–23, doi:10.3762/bjnano.1.4

• scale of typically a decade is not at all compatible with superparamagnetism. A natural way out of this problem is to look for materials exhibiting an as high as possible magnetocrystalline anisotropy which suppresses fluctuations of the effective magnetic moment of the NPs [7]. For binary alloys like

• remedy of the problem [8], a thorough understanding of the reduced magnetocrystalline anisotropy in nanoparticles is still missing. The route to such an understanding is, however, tedious and requires highest possible particle quality. It turns out that the application of magnetic NPs for data storage