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

• heterostructures on the lateral mesoscale. By means of in situ post-processing of Pt- and Co-based nano-stripes prepared by focused electron beam induced deposition (FEBID) we are able to locally tune their coercive field and remanent magnetization. Whereas single Co-FEBID nano-stripes show no hysteresis, we find

• out easier to deposit self-assembled Co nanoparticles on top of Pt thin films [38] and thereby fabricate surface alloys formed at step edges of Pt single crystalline substrates. In that work [38], an increase of the coercive field and of the Co orbital magnetic momentum was observed and attributed to

• the formation of the CoPt L10 phase with strongly increased magnetic anisotropy compared to pure Co. Here, we employ direct writing of Pt and Co layers by FEBID and demonstrate by means of in situ post-processing how to locally tune the coercive field and the remanent magnetization of layered Co/Pt

PEGylated versus non-PEGylated magnetic nanoparticles as camptothecin delivery system

• Paula M. Castillo,
• Mario de la Mata,
• Maria F. Casula,
• José A. Sánchez-Alcázar and
• Ana P. Zaderenko

Beilstein J. Nanotechnol. 2014, 5, 1312–1319, doi:10.3762/bjnano.5.144

• and separation temperatures (Tmax and Tsep) as obtained by ZFC-FC magnetization curves; coercive field (Hc), saturation magnetization (Msat); residual magnetization (Mr) and residual versus saturation magnetization values (Mr/Msat) as obtained by the hysteresis curve collected at 5 K. Maximum loading

Organic and inorganic–organic thin film structures by molecular layer deposition: A review

• Pia Sundberg and
• Maarit Karppinen

Beilstein J. Nanotechnol. 2014, 5, 1104–1136, doi:10.3762/bjnano.5.123

Antiferromagnetic coupling of TbPc₂ molecules to ultrathin Ni and Co films

• David Klar,
• Svetlana Klyatskaya,
• Andrea Candini,
• Bernhard Krumme,
• Kurt Kummer,
• Philippe Ohresser,
• Valdis Corradini,
• Valentina de Renzi,
• Roberto Biagi,
• Loic Joly,
• Jean-Paul Kappler,
• Umberto del Pennino,
• Marco Affronte,
• Heiko Wende and
• Mario Ruben

Beilstein J. Nanotechnol. 2013, 4, 320–324, doi:10.3762/bjnano.4.36

• the connecting lines for the Ni data in the upper picture of Figure 3 do not represent the Ni hysteresis curve, because of the low density of magnetic field steps. A more precise representation of the Ni hysteresis and the corresponding coercive field can be seen in the lower figure. Since the

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

• coercive field HC, and the change of the normalized magnetization M/MS at the magnetic field strength H = HC The evaluation of these parameters for in- and out-of-plane measurements are given in Table 1, with the respective indices || and . For in- and out-of-plane measurements of samples prepared with

• particle species I, we find increasing values for the remanent magnetization MR and the coercive field HC with longer treatment times. In contrast to these observations, the experiments carried out on species II show no clear tendency for these particular values. Instead, we find an increasing in-plane and

• synthesized FePt nanoparticles at a temperature of 600 °C, Antoniak et al. [20] found evidence for the partial formation of the chemically ordered L10 state, which entailed a significant increase of the coercive field by a factor of 6 after thermal treatment. With the pure Co particles studied in this work

Highly ordered ultralong magnetic nanowires wrapped in stacked graphene layers

• Abdel-Aziz El Mel,
• Jean-Luc Duvail,
• Eric Gautron,
• Wei Xu,
• Chang-Hwan Choi,
• Benoit Angleraud,
• Agnès Granier and
• Pierre-Yves Tessier

Beilstein J. Nanotechnol. 2012, 3, 846–851, doi:10.3762/bjnano.3.95

• from the shape anisotropy resulting from the very high aspect ratio of these nanostructures [7][35][36][37][38][39][40][41][42][43]. Concerning the coercive field, it is slightly higher ( = 32 Oe) when the external magnetic field is applied parallel to the nanowire array, than the one measured for the

• interactions between separated lines are due to magnetostatic effects that become relevant when the line separation is typically less than the line width [38][42]. For a field applied parallel to the lines, the coercive field and the squareness are reduced when the line separation decreases [36][38][41]. As a

Tuning the properties of magnetic thin films by interaction with periodic nanostructures

• Ulf Wiedwald,
• Felix Haering,
• Stefan Nau,
• Carsten Schulze,
• Herbert Schletter,
• Denys Makarov,
• Alfred Plettl,
• Karsten Kuepper,
• Manfred Albrecht,
• Johannes Boneberg and
• Paul Ziemann

Beilstein J. Nanotechnol. 2012, 3, 831–842, doi:10.3762/bjnano.3.93

• with respect to the saturation magnetization, and small coercive field, the percolated Fe film of identical thickness exhibits a strongly enhanced coercive field of HC = 250 Oe. Moreover, the hysteresis is more S-shaped with slightly reduced remanent magnetization and large saturation field of about

• characterization techniques, such as SQUID magnetometry, it is convenient to determine the coercive field HC as a function of the geometric parameters t, d, and a of the samples, as shown in Figure 5b–d, respectively. In panel (b) HC is displayed as a function of the film thickness t for different remaining

• particle diameters. All samples were prepared from PS spheres with an initial diameter of a = 95 nm. The coercive field is found to be larger in all samples compared to the reference films having HC < 10 Oe. It is apparent that HC has a gradually shifting maximum moving from about t = 10 nm for d = 37 nm

Focused electron beam induced deposition: A perspective

• Michael Huth,
• Fabrizio Porrati,
• Christian Schwalb,
• Marcel Winhold,
• Roland Sachser,
• Maja Dukic,
• Jonathan Adams and
• Georg Fantner

Beilstein J. Nanotechnol. 2012, 3, 597–619, doi:10.3762/bjnano.3.70

• electron irradiated sample shows an increase by about two orders of magnitude. The conductivity levels off below 50 K and shows only a small residue of the conductance drop at 12 K. The Hall data indicate now a ferromagnetic state at room temperature with increasing coercive field as the sample is cooled

Distinguishing magnetic and electrostatic interactions by a Kelvin probe force microscopy–magnetic force microscopy combination

• Miriam Jaafar,
• Oscar Iglesias-Freire,
• Luis Serrano-Ramón,
• Manuel Ricardo Ibarra,
• Jose Maria de Teresa and
• Agustina Asenjo

Beilstein J. Nanotechnol. 2011, 2, 552–560, doi:10.3762/bjnano.2.59

• -plane coercive field higher than the magnetic field values to be applied in the experiments. In addition, micromagnetic simulations have been performed by means of the object oriented micromagnetic framework (OOMMF) code [41] and with the polycrystalline cobalt values [37] and a cell size of 5 nm. As

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

• ) films with micron-sized grains, local alloying at the film surface was established. Signatures of alloy formation were evident from magnetic investigations. Upon annealing to temperatures up to 380 °C, we found an increase both of the coercive field and of the Co orbital magnetic moment, indicating the

• 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

• (TA = 250 °C) a narrow hysteresis loop was observed with a coercive field of µ0HC = 27 mT on Pt(100) films, while no clear opening was detected for Co NPs on Pt(111), within the experimental uncertainties. The largest difference of coercive fields was obtained after annealing in the interval TA = 300

Ultrafine metallic Fe nanoparticles: synthesis, structure and magnetism

• Olivier Margeat,
• Marc Respaud,
• Catherine Amiens,
• Pierre Lecante and
• Bruno Chaudret

Beilstein J. Nanotechnol. 2010, 1, 108–118, doi:10.3762/bjnano.1.13

• measured under µoH = 1 mT. Inset shows the extracted temperature dependence of MS. AC susceptibility measured for various frequencies (symbols) and their fits (solid lines). Hysteresis loop measured at 2 K. Inset: enlargement near zero field showing the coercive field. Magnetization curves in the

Review and outlook: from single nanoparticles to self-assembled monolayers and granular GMR sensors

• Alexander Weddemann,
• Inga Ennen,
• Anna Regtmeier,
• Camelia Albon,
• Annalena Wolff,
• Katrin Eckstädt,
• Nadine Mill,
• Michael K.-H. Peter,
• Jochen Mattay,
• Carolin Plattner,
• Norbert Sewald and
• Andreas Hütten

Beilstein J. Nanotechnol. 2010, 1, 75–93, doi:10.3762/bjnano.1.10

• significance of dipolar coupling increases. A manifestation of this type of interaction is the induced hysteresis in the detection signal. The coercive field of the ΔTMR-hysteresis loop coincides with the coercive field measured by an alternating gradient magnetometer (AGM). Once a second critical value is

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

• etching (details are given in section 1.4) led to Co NPs with an average particle height of 8 ± 1 nm (measured by AFM) with an interparticle distance D ≈ 60 nm (see inset of Figure 10 (b)). The measured hysteresis loop showed a sample saturation moment, remanent magnetization and a coercive field of MS

• = 5∙10–6 emu, MR = 26%, HC = 150 Oe, respectively. This value of the coercive field is typical for Co NPs [32]. An MR of 26%, which is only about half the value expected for Stoner-Wohlfarth NPs, suggests that already a significant amount of NPs is in the superparamagnetic state at T = 29 K. Comparing