Magnetic properties of optimized cobalt nanospheres grown by focused electron beam induced deposition (FEBID) on cantilever tips

• Soraya Sangiao,
• César Magén,
• Darius Mofakhami,
• Grégoire de Loubens and
• José María De Teresa

Beilstein J. Nanotechnol. 2017, 8, 2106–2115, doi:10.3762/bjnano.8.210

• nanosphere [11]. From the maximal relative variation of the cantilever frequency (1.2% in Figure 6a) and knowing the cantilever spring constant and the second spatial derivative of the magnetic field ((1.5 ± 0.3) × 109 T/m2) in which the measurements are operated, one can estimate the magnetic moment of the

• standard laser deflection technique is used to monitor the displacement of the cantilever. Its resonance frequency is tracked using a piezoelectric bimorph and a feedback electronic circuit based on a phase lock loop. The relative frequency shift due to the force acting on the magnetic moment m of the

Electronic structure, transport, and collective effects in molecular layered systems

• Torsten Hahn,
• Tim Ludwig,
• Carsten Timm and
• Jens Kortus

Beilstein J. Nanotechnol. 2017, 8, 2094–2105, doi:10.3762/bjnano.8.209

• similar fluorinated copper phthalocyanine (F16CoPc), has demonstrated the occurrence of hybridization [11]. It was proved that a local charge transfer which affects only the transition-metal centers changes the charge state of the transition metal and is directly related to a change of its magnetic moment

• density of states as obtained from the DFT calculations. While the electronic structure of CoPc and F16CoPc is qualitative similar after surface contact, the manganese center in the F16CoPc/MnPc yields a larger local magnetic moment and more strongly occupied metal 3d states close to the Fermi level. Both

Charge transfer from and to manganese phthalocyanine: bulk materials and interfaces

• Florian Rückerl,
• Daniel Waas,
• Bernd Büchner,
• Martin Knupfer,
• Dietrich R. T. Zahn,
• Francisc Haidu,
• Torsten Hahn and
• Jens Kortus

Beilstein J. Nanotechnol. 2017, 8, 1601–1615, doi:10.3762/bjnano.8.160

• ][8]. Phthalocyanine molecules can harbor a number of metal ions, in particular transition-metal ions such as cobalt, iron or manganese. A special characteristic of transition-metal centered phthalocyanines is, that transition-metal ions often are characterized by a magnetic moment, and therefore such

• possible [43][45][46]. The EELS cross section is proportional to Im(−1/ε) (ε is the dielectric function). In this way, one can investigate valence-band excitations (cf. optical methods) and the element-projected unoccupied density of states. Also, access to orbital selective occupations and the magnetic

• moment of open shells is accessible. Spectroscopic ellipsometry [47][48][49] measures the change in the light polarization after reflection on a sample surface. This information allows for the determination of the real and the imaginary part of the dielectric function. XAS [42][50] is equivalent to EELS

Formation of ferromagnetic molecular thin films from blends by annealing

• Peter Robaschik,
• Ye Ma,
• Salahud Din and
• Sandrine Heutz

Beilstein J. Nanotechnol. 2017, 8, 1469–1475, doi:10.3762/bjnano.8.146

• reached and is not saturated at the maximum field of 7 T. This is in line with earlier reports on β-MnPc powder and single-crystal samples [10][11][27][28]. However, to our knowledge no reports on the coercivity in β-MnPc thin films from OMBD have been made. The magnetic moment at 7 T amounts to 2.1 μB

• per MnPc molecules, which is below the expected value of 3 μB for a system with S = 3/2. This can be explained by the absence of magnetic saturation at the maximum available field and the reduction of magnetic moment due to crystal field effects [29]. Due to the observation of a reasonable magnetic

• -field cooled (ZFC) protocols. The average magnetic moment per MnPc molecule increases rapidly below 20 K and shows a bifurcation in both ZFC measurements at 3 K, whereas a steady increase in the FC data can be observed. This finding coincides with reports on DC and AC susceptibility measurements of pure

Deposition of exchange-coupled dinickel complexes on gold substrates utilizing ambidentate mercapto-carboxylato ligands

• Martin Börner,
• Laura Blömer,
• Marcus Kischel,
• Peter Richter,
• Georgeta Salvan,
• Dietrich R. T. Zahn,
• Pablo F. Siles,
• Maria E. N. Fuentes,
• Carlos C. B. Bufon,
• Daniel Grimm,
• Oliver G. Schmidt,
• Daniel Breite,
• Bernd Abel and
• Berthold Kersting

Beilstein J. Nanotechnol. 2017, 8, 1375–1387, doi:10.3762/bjnano.8.139

• for 7 and 8 between 2 and 330 K in applied external magnetic fields of B = 0.1, 0.5, and 1.0 T. Figure 4 shows the susceptibility data (per dinuclear complex) in the form of μeff versus T plots at 1 T. Both complexes behave similarly. Thus, for complex 7, the effective magnetic moment per dinuclear

• complex at 300 K increases from 4.78·μB (8: 4.80 μB) at 300 K to a maximum value of 5.36 μB at 23 K (8: 5.27 μB). On lowering the temperature further the magnetic moment decreases to 4.60 μB (or 4.34 μB) at 2 K. This behavior suggests that the electron spins on the two Ni(II) (S = 1) ions are coupled by

• an intramolecular ferromagnetic exchange interaction. This would lead to an St = 2 ground state, in agreement with other carboxylato-bridged compounds supported by L. The decrease in χMT below 20 K can be attributed to zero-field splitting of Ni(II) [51]. The magnetic moment data were analyzed in

Characterization of ferrite nanoparticles for preparation of biocomposites

• Urszula Klekotka,
• Magdalena Rogowska,
• Dariusz Satuła and
• Beata Kalska-Szostko

Beilstein J. Nanotechnol. 2017, 8, 1257–1265, doi:10.3762/bjnano.8.127

• Fe in a way that the Fe magnetic moment increases when Co is in the nearest surrounding of the Fe nuclei. Such a scenario is in good agreement with the observation in other systems [26]. Particles substituted with Mn are very close to superparamagnetic TB, which is estimated to occur when the

Formation and shape-control of hierarchical cobalt nanostructures using quaternary ammonium salts in aqueous media

• Ruchi Deshmukh,
• Anurag Mehra and
• Rochish Thaokar

Beilstein J. Nanotechnol. 2017, 8, 494–505, doi:10.3762/bjnano.8.53

• (monomers) in presence of quaternary ammonium salts. Hydroxide ions and a magnetic moment of the monomers are essential to induce shape anisotropy in the nanostructures. The cobalt nanoplates are studied in detail, and a growth mechanism based on collision, aggregation, and crystal consolidation is proposed

• microscopy; hierarchical nanostructures; magnetic moment; tetramethylazanium hydroxide (TMAH); Introduction The synthesis of ferromagnetic nanomaterials with complex functional architectures has seen rapid development during the past decade [1][2][3]. Cobalt nanostructures form an important class of

• experimental conditions, with the exception of an elevated temperature (50 °C) nanorods are obtained (Figure 1d). We therefore hypothesize that a synergistic effect of OH− adsorption [23][24][29][30], inherent magnetic moment, controlled aggregation and growth temperature are the factors influencing the

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

• (distances below 20 nm down to contact) in the center of the laser spot had virtually no impact on the heat-assisted written magnetic feature. Three different tip types were used: plain Si tips, Au-coated Si tips and MFM tips with low magnetic moment (CoCr coating). All featured a geometry which allowed for

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

• drastically affects the intrinsic properties of this system by reducing the magnetization in comparison to the bulk. Keywords: bimetallic nanoparticles; magnetic moment and anisotropy; metamagnetic transition; Introduction Magnetic bimetallic nanoparticles (NPs) are very attractive systems not only from a

• , both FeRh and FeCo bulk alloys present a CsCl-type (B2) chemically ordered phase at room temperature (Figure 1) with the competition between several magnetic orderings for FeRh and a huge magnetic moment for soft FeCo according to the Slater–Pauling graph. It is interesting to examine the chemical and

• temperatures with respective values of 3μB and 1μB [13]. The ferromagnetic order increases slightly for smaller nanoparticles as confirmed from XMCD measurements on annealed 2 nm FeRh (see Figure 10). It should be noted that the total magnetic moment of Rh which is expected to be non-magnetic in bulk

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

• -prepared ZFO nanoparticles at an applied field of 10 mT are shown in Figure 5. As seen, the magnetic moment continuously increases until a maximum, Tmax, is reached at about 22 K. The fact that this maximum is rather sharp supports the size uniformity of the particles with a similar magnetic anisotropy

• environment. These data can be fitted using a simple Langevin model (L(x) with additional paramagnetic susceptibility term) of the form M = M0L(x) + kH with L(x) = coth(x) – 1/x and x = µH/(kBT), where M0 is the magnetization of the superspin glass part, k is the paramagnetic susceptibility, µ is the magnetic

• moment per cluster, kB is the Boltzmann’s constant and T is the temperature. The best fit was obtained with M0, k and µ values equal to 0.84 µB/f.u., 7.8 × 10–2 emu/(T × f.u.) and 1090 µB, respectively. Using these data and assuming a spherical cluster shape (with eight f.u. per unit cell), the cluster

Multiwalled carbon nanotube hybrids as MRI contrast agents

• Nikodem Kuźnik and
• Mateusz M. Tomczyk

Beilstein J. Nanotechnol. 2016, 7, 1086–1103, doi:10.3762/bjnano.7.102

• according to their magnetic moment (and the content of iron), so the researchers were able to separate mechanically the most iron-enriched hybrids from the rest of the product. Another example comes from Lamanna's research, where enhanced uptake of CNTs by PC3 tumor cells directly above a neodymium magnet

• millimolar concentration of the CA (Equation 1). Relaxivity (with a commonly used unit of mM−1s−1) is a derivative of the magnetic moment of the metal and its complex or the net magnetic moment of the nanoparticle [4]. The Solomon–Bloembergen–Morgan (SBM) theory is a well-established description of

• coordination via neighboring ligands and is given in Equation 2 and Equation 3. These hold for a moderate proton residence time τM ≈ 10 ns with C being a constant, q the number of inner-sphere water molecules, µeff the effective magnetic moment, τC the molecular correlation time, r the metal–H distance, τS the

Signal enhancement in cantilever magnetometry based on a co-resonantly coupled sensor

• Julia Körner,
• Christopher F. Reiche,
• Thomas Gemming,
• Bernd Büchner,
• Gerald Gerlach and
• Thomas Mühl

Beilstein J. Nanotechnol. 2016, 7, 1033–1043, doi:10.3762/bjnano.7.96

• magnetometry, Δk does not only depend on the interaction of the magnetic moment m of the sample with the external magnetic field H but also on the effective length of the cantilever Leff [6][7]. Furthermore, by assuming a simple Stoner–Wohlfarth single domain particle, the magnetic interaction is related to

• the coupled system. Since the effective magnetic monopole moment has to be the same for both peaks we calculate the mean value and finally obtain q = (3.7 ± 0.7) · 10−10 A·m, which corresponds to a magnetic moment of approximately 4 · 108μB (CNT length 10 μm). Geometric effective magnetic monopole

• the noise limits for each subsystem, indicating a range of the sensitivity for the coupled system. In standard cantilever magnetometry the noise limits the detectable frequency shift and, hence, the minimal detectable magnetic moment. The thermal limit for the frequency shift for a cantilever is given

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

• quantum interference device (SQUID) magnetic moment measurements. The triplet spin-valve effect has been investigated for different layer thicknesses, dF1, of F1 and was found to decay with increasing dF1. The data is described by an empirical model and, moreover, by calculations using the microscopic

• , the Co film is still in the mono-domain state with in-plane magnetization, while the Cu41Ni59 film is expected to exhibit a local net magnetization along its easy axis perpendicular to the layer (although the total magnetic moment of the layer is zero). Thus, with a magnetic field applied parallel to

• 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

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

• approximation as long as the antiferromagnetic coupling between the two sublattices of the simulated material is stronger than other effects. In this case, the magnetic moments of the two sublattices can be locally summarized to one magnetic moment (e.g., one macrospin). The LLB equation requires several

• switched due to misaligned adjacent antidots, breaking the alternating pattern. The arising periodic structure of bright (positive) and dark (repulsive) interactions with the MFM tip is described best using magnetic charges as suggested before [44]. We assign the charges ±qi = µ/l with µ being the magnetic

• moment of a bridge and l its length to each end of the i-th bridge, respectively. With three bridges being connected to each vertex, there are a total of four possible charge states a vertex can attain: qvertex = ±q or qvertex = ±3q. The ±3q states would result in a three times higher signal than the ±q

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

• Fe3O4 NPs have a squareness value of 0.15. Since a theoretical squareness value for a uniaxial system of magnetite bulk material is 0.5, our values are in general smaller due to the frustration of the magnetic moment at the NP surface [37]. But obviously the NP assembly can reduce this frustration

Sub-monolayer film growth of a volatile lanthanide complex on metallic surfaces

• Hironari Isshiki,
• Jinjie Chen,
• Kevin Edelmann and
• Wulf Wulfhekel

Beilstein J. Nanotechnol. 2015, 6, 2412–2416, doi:10.3762/bjnano.6.248

• metal-organic molecules with magnetic-ion cores exhibit long spin-relaxation times for the reversal of the localized magnetic moment at low temperatures. These molecules are called single-molecule magnets (SMMs), because the magnetic properties are attributed to the individual single molecules as a

• result of the quantum mechanical interaction of the local magnetic moment and the ligand field [1]. Lanthanide-based SMMs have attracted much interest due to the potentially huge energy barrier for the reversal of magnetization [2]. This is an advantage from an applications viewpoint for magnetic storage

An adapted Coffey model for studying susceptibility losses in interacting magnetic nanoparticles

• Mihaela Osaci and
• Matteo Cacciola

Beilstein J. Nanotechnol. 2015, 6, 2173–2182, doi:10.3762/bjnano.6.223

• -domain nanoparticle, it is possible to see how the energy barriers, expressed as a function of the domain wall movement, are relatively small if compared with the reversal of the complete magnetic moment. Thus, multi-domain nanoparticles are magnetically “softer” than single-domain nanoparticles

• ][10][11][12][13][14][15]. It is well known that the magnetic monodomain nanoparticles exhibit unstable behaviour of their magnetic moments due to the thermal agitation, i.e., the magnetic moment of the nanoparticle can randomly change direction under the influence of temperature. This is called

• is a solid-state mechanism that occurs within the nanoparticle. It corresponds to a switching of the magnetic moment between two equilibrium positions. The latter is due to the physical rotation of nanoparticle within the colloidal solution. Changing in orientation of the magnetic moment of a

Self-assembly mechanism of Ni nanowires prepared with an external magnetic field

• Xiaoyu Li,
• Hu Wang,
• Kenan Xie,
• Qin Long,
• Xuefei Lai and
• Li Liao

Beilstein J. Nanotechnol. 2015, 6, 2123–2128, doi:10.3762/bjnano.6.217

• the dipole magnetic moment of a nanoparticle is proportional to its volume [31]. Similarly, the interaction between the nanoparticle and the external magnetic field is also negligible, thus the motion of Ni nanoparticles cannot be influenced by the external magnetic field. As the reaction proceeds

Magnetic reversal dynamics of a quantum system on a picosecond timescale

• Nikolay V. Klenov,
• Alexey V. Kuznetsov,
• Igor I. Soloviev,
• Sergey V. Bakurskiy and
• Olga V. Tikhonova

Beilstein J. Nanotechnol. 2015, 6, 1946–1956, doi:10.3762/bjnano.6.199

• process in natural and artificial atomic systems by means of short magnetic pulses. In terms of the simplest model of a two-level system with a magnetic moment, we analyze the possibility of a fast magnetization reversal on the picosecond timescale induced by oscillating or short unipolar magnetic pulses

• framework of the macroscopic theory of the magnetic moment, which allows for the comparison and explanation of the quantum and classical behavior. Keywords: atomic-based qubits; magnetization reversal; quantum state control; RSFQ; superconducting qubits; Introduction The study of magnetic moment dynamics

• in atomic systems (including Rydberg atoms) is one of the simplest ways to monitor the evolution of quantum states. Two-level quantum systems with a well-defined magnetic moment of two magnetic basis states, and , continue to attract considerable attention in the context of the development of modern

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

• -cooled (ZFC) and field-cooled (FC) procedures under an applied magnetic field of 500 Oe. For the ZFC/FC measurements, the sample was first cooled without a field from room temperature to 2 K. Thereafter, a 500 Oe magnetic field was applied and the magnetic moment was recorded upon increasing temperature

• to obtain the ZFC curve. For the FC curve, the sample was cooled from 300 K under a field of 500 Oe and the magnetic moment was recorded upon decreasing temperature. Schematic of the core/shell/shell Mn:ZnS/ZnS/Fe3O4 QD synthesis. XRD patterns of (a) Mn:ZnS/ZnS, (b–e) Mn:ZnS/ZnS/Fe3O4 (1), (1.5), (2

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

• higher value of magnetic moment than nanoparticles (NPs) of comparable volume [10][11]. But they have not taken into account that the compared materials have not been exactly the same in terms of their chemical compositions. Besides that, as far as we know, nobody has reported any experimental results

Thermal treatment of magnetite nanoparticles

• Beata Kalska-Szostko,
• Urszula Wykowska,
• Dariusz Satula and
• Per Nordblad

Beilstein J. Nanotechnol. 2015, 6, 1385–1396, doi:10.3762/bjnano.6.143

• particles are to some extent transformed to hematite by this process. This was learned from the appearance of anomalies in the M vs T curves near 250 K, reflecting the Morin transition [40]. Also, the magnetic moment of the annealed sample is significantly lower and the blocking temperature can be estimated

The convenient preparation of stable aryl-coated zerovalent iron nanoparticles

• Olga A. Guselnikova,
• Andrey I. Galanov,
• Anton K. Gutakovskii and
• Pavel S. Postnikov

Beilstein J. Nanotechnol. 2015, 6, 1192–1198, doi:10.3762/bjnano.6.121

• pure metal NPs. We also conclude that this approach can be applicable for medicinal research since water is the reaction solvent and it produces materials with a high anticipated magnetic moment, stable covalent binding, and a high density of functional groups. The proposed synthesis strategy of ZVI

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

• external magnetic field flips the magnetization in the opposite direction. The switching field must overcome the FM/AFM coupling which is proportional to J multiplied by the cluster surface area πR2, where R is the cluster radius. On the other hand the bigger the total magnetic moment of the cluster (which

Interaction of electromagnetic radiation in the 20–200 GHz frequency range with arrays of carbon nanotubes with ferromagnetic nanoparticles

• Agylych Atdayev,
• Alexander L. Danilyuk and
• Serghej L. Prischepa

Beilstein J. Nanotechnol. 2015, 6, 1056–1064, doi:10.3762/bjnano.6.106

• other words, the nanocomposite impedance compensates for the magnetic moment created by the NP in the carbon matrix at a fixed frequency range. When no valley is present in the μ(ω) dependence, the impedance of the magnetic dipole (and consequently, its polarizability) is determined by the permeability