Photocatalytic degradation of methylene blue under visible light by cobalt ferrite nanoparticles/graphene quantum dots

• Vo Chau Ngoc Anh,
• Le Thi Thanh Nhi,
• Le Thi Kim Dung,
• Dang Thi Ngoc Hoa,
• Nguyen Truong Son,
• Nguyen Thi Thao Uyen,
• Nguyen Ngoc Uyen Thu,
• Le Van Thanh Son,
• Le Trung Hieu,
• Tran Ngoc Tuyen and
• Dinh Quang Khieu

Beilstein J. Nanotechnol. 2024, 15, 475–489, doi:10.3762/bjnano.15.43

• ferrites with high coercive field and magnetization, while the hysteresis loops of CF/GQDs are reversible, indicating that CF/GQDs exhibit superparamagnetic characteristics. The magnetic saturation values of the CF/GQDs-140, -180 and -200 samples are 0, 11.1, and 36.3 emu/g, respectively, at room

TEM sample preparation of lithographically patterned permalloy nanostructures on silicon nitride membranes

• Joshua Williams,
• Michael I. Faley,
• Joseph Vimal Vas,
• Peng-Han Lu and
• Rafal E. Dunin-Borkowski

Beilstein J. Nanotechnol. 2024, 15, 1–12, doi:10.3762/bjnano.15.1

• –iron alloy (80 atom % Ni and 20 atom % Fe) that has a small coercive field (Hc) [17] and low magnetostriction (λs) [18], as well as high permeability and high saturation magnetization (Ms) [19]. TEM offers high spatial resolution for magnetic imaging. TEM-based magnetic imaging techniques such as

• external magnetic field applied using the objective lens was first studied using Lorentz TEM. The initial magnetic configuration of the Py nanodisks after relaxation is shown in Figure 13c. In order to ascertain the coercive field of the sample, we applied the external field until the contrast was no

Ultrafast signatures of magnetic inhomogeneity in Pd_1−xFe_x (x ≤ 0.08) epitaxial thin films

• Andrey V. Petrov,
• Sergey I. Nikitin,
• Lenar R. Tagirov,
• Amir I. Gumarov,
• Igor V. Yanilkin and
• Roman V. Yusupov

Beilstein J. Nanotechnol. 2022, 13, 836–844, doi:10.3762/bjnano.13.74

• temperature. This field strength ensures a uniformly magnetized state of the film since the coercive field of the studied samples does not exceed 25 Oe. The sample temperature was set and maintained using a Lakeshore 335 temperature controller with an accuracy of 0.1 K. Results Figure 1 shows the dependency

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

• of the magnetization reversal are shown in Figure 3c and 3d, respectively. Since the projection of the magnetic field onto the film plane is small (Hx ≈ 0.12Hxz), the coercive field values are increased and the double jumps becomes smeared. Current at an angle to [100] direction, field H in the XY

In situ transport characterization of magnetic states in Nb/Co superconductor/ferromagnet heterostructures

• Olena M. Kapran,
• Roman Morari,
• Taras Golod,
• Evgenii A. Borodianskyi,
• Vladimir Boian,
• Andrei Prepelita,
• Nikolay Klenov,
• Anatoli S. Sidorenko and
• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2021, 12, 913–923, doi:10.3762/bjnano.12.68

• by SQUID magnetometry in a field parallel to the film in the normal state at T > Tc. A significant hysteresis of M(H) reveals the in-plane anisotropy of Co films (albeit with a small coercive field, HC ≈ 30 Oe), consistent with earlier studies [44][45][46][47]. Figure 1c shows a numerical simulation

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

• ferromagnet with a low coercive field [41]. It is important that magnetic properties of epitaxial Pd1−xFex films are precisely controlled with the iron content x [41], and a perfect cube-on-cube epitaxy is realized with either the MgO(001) substrate or with the superconducting VN layers in any sequence

Superconducting switching due to a triplet component in the Pb/Cu/Ni/Cu/Co₂Cr_1−xFe_xAl_y spin-valve structure

• Andrey Andreevich Kamashev,
• Nadir Nurgayazovich Garif’yanov,
• Aidar Azatovich Validov,
• Joachim Schumann,
• Vladislav Kataev,
• Bernd Büchner,
• Yakov Victorovich Fominov and
• Ilgiz Abdulsamatovich Garifullin

Beilstein J. Nanotechnol. 2019, 10, 1458–1463, doi:10.3762/bjnano.10.144

• samples were covered with a protective Si3N4 layer to prevent oxidation of the Pb layer. The Ni layer with the thickness dNi≤ 2 nm has coercive field of the order of 2 kOe [20]. In the present study the Ni layer is deposited at a substrate temperature of Tsub≈ 150 K. Therefore its coercive field should be

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

• observed that the heat efficiency of soft Fe3O4 is about 4 times larger than that of hard CoFe2O4 ferrite, which was attributed to the high coercive field of samples compared with the external field amplitude. Keywords: anisotropy; cobalt; ferrite; Henkel plots; hyperthermia therapy; nanoparticles

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

• temperature (TB), saturation magnetization (MS) and coercive field (HC) of the CoxFe3−xO4 nanoparticles. Acknowledgements We would like to thank M. Ludovic Mouton and Dr. Sophie Nowak (Université Paris Diderot) for their technical support on TEM and XRF analysis, respectively. We would also like to thank

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

• spectra. Isomer shift (IS), quadrupole splitting (QS), hyperfine magnetic field (Bhf) and relative percentage area of the components. All measurements have an uncertainty of 1 in the last digit. Remanent magnetization (MR), saturation magnetization (MS), reduced remanence (MR/MS) and coercive field

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

• 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

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

• structures in Ni nanowires, leading to magnetic moments enhanced by 25% with respect to bulk Ni. Both saturation and coercive field of the nanowire arrays are much lower than those of single nanowires (with material-related magnetic parameters selected from the best agreement between simulation and

• experiment). The much lower coercive field in case of the nanowires array (about 0.01 T) as compared to the switching field of a single nanowire (of the order of 0.1 T) in parallel geometry, as well as the much smoother reversal in the first case hint to a progressive rotation of magnetic moments of

Field-controlled ultrafast magnetization dynamics in two-dimensional nanoscale ferromagnetic antidot arrays

• Anulekha De,
• Sucheta Mondal,
• Sourav Sahoo,
• Saswati Barman,
• Yoshichika Otani,
• Rajib Kumar Mitra and
• Anjan Barman

Beilstein J. Nanotechnol. 2018, 9, 1123–1134, doi:10.3762/bjnano.9.104

• can be varied to tune the magnonic spectra and magnetization dynamics in ferromagnetic antidot lattices. Several studies have been focused on the engineering of the coercive field, magnetoresistance and anisotropy properties on domain formation and the magnetization reversal mechanism with the change

Magnetic characterization of cobalt nanowires and square nanorings fabricated by focused electron beam induced deposition

• Federico Venturi,
• Gian Carlo Gazzadi,
• Amir H. Tavabi,
• Alberto Rota,
• Rafal E. Dunin-Borkowski and
• Stefano Frabboni

Beilstein J. Nanotechnol. 2018, 9, 1040–1049, doi:10.3762/bjnano.9.97

• and Figure 2d, respectively. The square shape of the loop is a sign of the single domain character that results from the high aspect ratio and shape anisotropy of the NW. A coercive field of approximately 10 mT is measured from the loop and is consistent with previous measurements on Co NWs [42]. High

• of a square hysteresis loop with a coercive field of approximately 10 mT. L-TEM images of square nanorings revealed a horseshoe magnetic state, which could be changed to an opposite horseshoe state by reversing the magnetic field applied in situ. By increasing the external magnetic field and

Single-crystalline FeCo nanoparticle-filled carbon nanotubes: synthesis, structural characterization and magnetic properties

• Rasha Ghunaim,
• Maik Scholz,
• Christine Damm,
• Bernd Rellinghaus,
• Rüdiger Klingeler,
• Bernd Büchner,
• Michael Mertig and
• Silke Hampel

Beilstein J. Nanotechnol. 2018, 9, 1024–1034, doi:10.3762/bjnano.9.95

• -filled CNTs show significant enhancement in the coercive field as compared to the corresponding bulk material, which make them excellent candidates for several applications such as magnetic storage devices. Keywords: carbon nanotubes; crystal structure; encapsulation; Fe–Co binary nanoparticles

• data in Figure 7 demonstrate a robust enhancement in the hardness of the magnetic nanoparticles of the annealed Fe50Co50@CNT samples compared to the bulk material. Coercive field (Hc) measurements for the Fe50Co50 nanoparticles prepared by the first and second filling approaches at 300 K yield were Hc

• ≈ 373 ± 2 Oe and Hc ≈ 185 ± 2 Oe (Figure 7b), respectively. These values are approximately 200 times higher than for the bulk material at the same temperature (Hc (bulk) = 0.68 Oe) [22][54]. The increase in the coercive field as the particle size decreases can be attributed to the size dependence of

Beyond Moore’s technologies: operation principles of a superconductor alternative

• Igor I. Soloviev,
• Nikolay V. Klenov,
• Sergey V. Bakurskiy,
• Mikhail Yu. Kupriyanov,
• Alexander L. Gudkov and
• Anatoli S. Sidorenko

Beilstein J. Nanotechnol. 2017, 8, 2689–2710, doi:10.3762/bjnano.8.269

Dynamic behavior of a nematic liquid crystal mixed with CoFe₂O₄ ferromagnetic nanoparticles in a magnetic field

• Emil Petrescu,
• Cristina Cirtoaje and
• Cristina Stan

Beilstein J. Nanotechnol. 2017, 8, 2467–2473, doi:10.3762/bjnano.8.246

• field intensity of 790 kA/m and a coercive field of 239 kA/m. The cell thickness was set by a pair of 180 micrometer Mylar sheets and planar alignment was obtained by coating the glass plates with a solution of 0.1% PVA and rubbing them with a soft cloth. The experimental setup used for the measurement

Grazing-incidence optical magnetic recording with super-resolution

• Gunther Scheunert,
• Sidney. R. Cohen,
• René Kullock,
• Ryan McCarron,
• Katya Rechev,
• Ifat Kaplan-Ashiri,
• Ora Bitton,
• Paul Dawson,
• Bert Hecht and
• Dan Oron

Beilstein J. Nanotechnol. 2017, 8, 28–37, doi:10.3762/bjnano.8.4

• smaller than in (a). Magnetic recording medium: (a) TEM cross-section image with indication of the stack setup used for modelling. (b) Thermo-magnetic plot of the coercive field strength (blue), normalized to the room temperature value, indicating switching field requirements. Zero-field-cooled (ZFC

Antitumor magnetic hyperthermia induced by RGD-functionalized Fe₃O₄ nanoparticles, in an experimental model of colorectal liver metastases

• Oihane K. Arriortua,
• Eneko Garaio,
• Borja Herrero de la Parte,
• Maite Insausti,
• Luis Lezama,
• Fernando Plazaola,
• Jose Angel García,
• Jesús M. Aizpurua,
• Maialen Sagartzazu,
• Mireia Irazola,
• Nestor Etxebarria,
• Ignacio García-Alonso,
• Alberto Saiz-López and
• José Javier Echevarria-Uraga

Beilstein J. Nanotechnol. 2016, 7, 1532–1542, doi:10.3762/bjnano.7.147

• of the Fe3O4@OA sample (Figure 2). The absence of a coercive field or remanence in the hysteresis loop recorded at 300 K is indicative of a superparamagnetic behavior of the sample. The saturation magnetization value obtained from the hysteresis loops at 300 K is 78.4 emu/g Fe3O4, which slightly

• (87.2 emu/g Fe3O4) to nearly reach the bulk value for magnetite. The coercive field value observed at 5 K is around 0.05 kOe, which is very similar to that observed in magnetite nanoparticles of similar size [41]. The measurement of magnetization versus temperature after cooling at zero-field-cooled

Microwave synthesis of high-quality and uniform 4 nm ZnFe₂O₄ nanocrystals for application in energy storage and nanomagnetics

• Christian Suchomski,
• Ben Breitung,
• Ralf Witte,
• Michael Knapp,
• Sondes Bauer,
• Tilo Baumbach,
• Christian Reitz and
• Torsten Brezesinski

Beilstein J. Nanotechnol. 2016, 7, 1350–1360, doi:10.3762/bjnano.7.126

• temperature Tf ≈ 22 K. Figure 7a–c shows results from field-dependent SQUID magnetometry. The M(H) curve measured at 5 K (Figure 7a,b) indicates ferrimagnetic behavior with a coercive field HC ≈ 12 mT. As evident, the magnetization is not completely saturated. Similar observations have been made for other

Thickness dependence of the triplet spin-valve effect in superconductor–ferromagnet–ferromagnet heterostructures

• Daniel Lenk,
• Vladimir I. Zdravkov,
• Jan-Michael Kehrle,
• Günter Obermeier,
• Aladin Ullrich,
• Roman Morari,
• Hans-Albrecht Krug von Nidda,
• Claus Müller,
• Mikhail Yu. Kupriyanov,
• Anatolie S. Sidorenko,
• Siegfried Horn,
• Rafael G. Deminov,
• Lenar R. Tagirov and
• Reinhard Tidecks

Beilstein J. Nanotechnol. 2016, 7, 957–969, doi:10.3762/bjnano.7.88

• interaction with a CoOx film. This shifts the coercive field of the Co film, Hc,Co, to high negative fields with respect to the cooling-field direction, yielding clear separation of the coercive fields of the two ferromagnetic layers [55]. At the small negative coercive field of the Cu41Ni59 film, Hc,CuNi

• was enlarged by a factor of 5. The corresponding equation is given by with m(H) being the magnetic moment, ms the saturation magnetic moment, Hc the coercive field, and Ht a threshold field, determining the field (relative to the coercive field), at which half of the saturation magnetization is

• line is the resistance level, at which we evaluated the transition temperature, Tc, at one half of the normal state resistance. There are no obvious peculiarities in the shape of the transition curves, even at the coercive field of Cu41Ni59. At this field the transition is shifted towards lower

Magnetic switching of nanoscale antidot lattices

• Ulf Wiedwald,
• Joachim Gräfe,
• Kristof M. Lebecki,
• Maxim Skripnik,
• Felix Haering,
• Gisela Schütz,
• Paul Ziemann,
• Eberhard Goering and
• Ulrich Nowak

Beilstein J. Nanotechnol. 2016, 7, 733–750, doi:10.3762/bjnano.7.65

• at a lateral resolution better than the structural grain size of the antidots based on magneto-optical Kerr (MOKE) microscopy is possible and the determination of interaction- and coercive field-distributions by fast MOKE related first-order reversal curves (FORC) is feasible. The hands-on

• films starting from the antidots’ rims. In practice, however, it turned out that neither the magnetisation of the samples nor their coercive field changed significantly over time scales of several months. The experimental parameters used for preparing the antidot samples presented below are given in the

• nanostructures. Hence, it is necessary to use complex and sophisticated synchrotron methods like STXM and photoemission electron microscopy (PEEM) or magnetic force microscopy. One possible way, however, gaining further microscopic understanding of interaction phenomena and coercive field distributions in

Hemolysin coregulated protein 1 as a molecular gluing unit for the assembly of nanoparticle hybrid structures

• Tuan Anh Pham,
• Andreas Schreiber,
• Elena V. Sturm (née Rosseeva),
• Stefan Schiller and
• Helmut Cölfen

Beilstein J. Nanotechnol. 2016, 7, 351–363, doi:10.3762/bjnano.7.32

• leading to a higher MR/MS ratio. The coercive field (HC) also stays unchanged for both samples at 100 Oe. The blocking temperature, Tb, (the maximum in the zero-field cooling (ZFC) curve), decreases from 94 K to 78 K as the hybrid structure is formed (Figure 10C). Hiroi et al. found that decreasing Tb for

A facile method for the preparation of bifunctional Mn:ZnS/ZnS/Fe₃O₄ magnetic and fluorescent nanocrystals

• Houcine Labiadh,
• Tahar Ben Chaabane,
• Romain Sibille,
• Lavinia Balan and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2015, 6, 1743–1751, doi:10.3762/bjnano.6.178

• change as well in the same manner for Mn:ZnS/ZnS/Fe3O4 QDs (1, 1.5 and 2). Surprisingly, the Mn:ZnS/ZnS/Fe3O4 (3) crystals exhibited reduced MR and M9T values, which were lower than those measured for (1.5) and (2) samples. However, its coercive field was the highest (Table 2). This likely originates

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

• determination of the coercive field (HC), which depends on the shape of the nanostructure. In the present work, we have used the Fe2(CO)9 precursor to grow iron nanowires by FEBID in the thickness range from 10 to 45 nm and width range from 50 to 500 nm. These nanowires exhibit an Fe content between 80 and 85

• indicate that these wires have a bell-type shape with a surface oxide layer of about 5 nm. Such features are decisive in the actual value of HC as micromagnetic simulations demonstrate. These results will help to make appropriate designs of magnetic nanowires grown by FEBID. Keywords: coercive field

• magnetic structures [19], the growth of three-dimensional nanowires [20][21] and the fabrication of nanospheres on scanning probe tips [22][23]. One of the crucial parameters to be controlled in such magnetic nanostructures grown by FEBID is the coercive field, HC, which corresponds to the magnetic field