Influence of the thickness of an antiferromagnetic IrMn layer on the static and dynamic magnetization of weakly coupled CoFeB/IrMn/CoFeB trilayers

• Deepika Jhajhria,
• Dinesh K. Pandya and
• Sujeet Chaudhary

Beilstein J. Nanotechnol. 2018, 9, 2198–2208, doi:10.3762/bjnano.9.206

• of the antiferromagnetic (AF) IrMn layer is investigated using magnetization hysteresis (M–H) and ferromagnetic resonance (FMR) measurements. The study shows that the two CoFeB layers are coupled via a long-range dynamic exchange effect through the IrMn layer up to a thickness of 6 nm. It is found

• . Keywords: ferromagnetic resonance; interlayer exchange coupling; magnetic damping; magnetic thin films; spin pumping; Introduction Traditionally, antiferromagnets (AF) are known to play only a static role by pinning adjacent ferromagnetic (FM) layers via exchange bias in spin-valve devices [1]. Recently

• between two FM layers through an AF layer. Motivated by this, we chose a rather uncommon CoFeB(10 nm)/IrMn(tIrMn)/CoFeB(10 nm) trilayer system to investigate the interlayer exchange coupling, spin transport, magnetic damping and magnetization reversal by carrying out ferromagnetic resonance (FMR) and

Increasing the performance of a superconducting spin valve using a Heusler alloy

• Andrey A. Kamashev,
• Aidar A. Validov,
• Joachim Schumann,
• Vladislav Kataev,
• Bernd Büchner,
• Yakov V. Fominov and
• Ilgiz A. Garifullin

Beilstein J. Nanotechnol. 2018, 9, 1764–1769, doi:10.3762/bjnano.9.167

• Abstract We have studied superconducting properties of spin-valve thin-layer heterostructures CoOx/F1/Cu/F2/Cu/Pb in which the ferromagnetic F1 layer was made of Permalloy while for the F2 layer we have taken a specially prepared film of the Heusler alloy Co2Cr1−xFexAl with a small degree of spin

• manipulate the transition temperature Tc of a superconductor by sandwiching it between two ferromagnetic insulators was thought of by de Gennes [1]. Regarding the case of metallic ferromagnets, the physical principle of a superconducting spin valve (SSV) is based on the idea proposed by Oh et al. in 1997 [2

• ] who calculated the pairing wave-function amplitude in a trilayer F1/F2/S (where F1 and F2 are ferromagnetic layers and S is a superconducting layer) and found out that the superconducting (SC) transition temperature Tc depends on the mutual orientation of the magnetizations M1 and M2 of the layers F1

Magnetic properties of Fe₃O₄ antidot arrays synthesized by AFIR: atomic layer deposition, focused ion beam and thermal reduction

• Juan L. Palma,
• Alejandro Pereira,
• Raquel Álvaro,
• José Miguel García-Martín and
• Juan Escrig

Beilstein J. Nanotechnol. 2018, 9, 1728–1734, doi:10.3762/bjnano.9.164

• properties of the film [13][14][15][16][17][18][19]. Thus, the antidot geometry can also be used to tailor the coercivity and the frequencies of the ferromagnetic resonance modes [20][21][22]. It is well known that there are numerous techniques for attaining magnetic antidot arrays such as e-beam [6][16], UV

Josephson effect in junctions of conventional and topological superconductors

• Alex Zazunov,
• Albert Iks,
• Miguel Alvarado,
• Alfredo Levy Yeyati and
• Reinhold Egger

Beilstein J. Nanotechnol. 2018, 9, 1659–1676, doi:10.3762/bjnano.9.158

• for concreteness, we here imagine the field B as independent local field coupled only to the QD spin. One could use, e.g., a ferromagnetic grain near the QD to generate it. This field here plays a crucial role because for B = 0, the S+QD part is spin rotation [SU(2)] invariant and the arguments of [31

Nanocomposites comprised of homogeneously dispersed magnetic iron-oxide nanoparticles and poly(methyl methacrylate)

• Sašo Gyergyek,
• David Pahovnik,
• Ema Žagar,
• Alenka Mertelj,
• Rok Kostanjšek,
• Miloš Beković,
• Marko Jagodič,
• Heinrich Hofmann and
• Darko Makovec

Beilstein J. Nanotechnol. 2018, 9, 1613–1622, doi:10.3762/bjnano.9.153

• -oxide nanoparticles with a size close to the superparamagnetic limit have been extensively studied because of their unique properties that can be exploited in a variety of applications. When the size of a single-domain ferromagnetic material is reduced below a certain critical value, the transition to

Interaction-tailored organization of large-area colloidal assemblies

• Silvia Rizzato,
• Elisabetta Primiceri,
• Anna Grazia Monteduro,
• Adriano Colombelli,
• Angelo Leo,
• Maria Grazia Manera,
• Roberto Rella and
• Giuseppe Maruccio

Beilstein J. Nanotechnol. 2018, 9, 1582–1593, doi:10.3762/bjnano.9.150

• theoretically driven route for a feasible fabrication of metal nanostructures has been demonstrated with this work. Concerning magnetic samples and their properties, a hysteresis loop of cobalt nanoholes is presented in Figure 5d as obtained by magneto-optic Kerr effect (MOKE) measurements – a ferromagnetic

Solid-state Stern–Gerlach spin splitter for magnetic field sensing, spintronics, and quantum computing

• Kristofer Björnson and
• Annica M. Black-Schaffer

Beilstein J. Nanotechnol. 2018, 9, 1558–1563, doi:10.3762/bjnano.9.147

• edge of a two-dimensional topological insulator can be used to construct a solid-state Stern–Gerlach spin splitter. By threading such a Stern–Gerlach apparatus with a magnetic flux, Aharanov–Bohm-like interference effects are introduced. Using ferromagnetic leads, the setup can be used to both measure

• ferromagnetic leads, the device can be used for sensitive measurements of magnetic field strengths. The same setup can also be used to implement a spintronic switch. Instead using normal metallic leads, we show that a switchable spintronics NOT-gate can be constructed. Finally, we also demonstrate how a

• concrete application, we consider a system with fully spin-polarized ferromagnetic leads only containing electrons with spin-up. Further, the SG spin splitter is assumed to be oriented at an angle φ = π/2, which forces the incoming spins to split equally into both channels. Because the leads only conduct

Spatial Rabi oscillations between Majorana bound states and quantum dots

• Jun-Hui Zheng,
• Dao-Xin Yao and
• Zhi Wang

Beilstein J. Nanotechnol. 2018, 9, 1527–1535, doi:10.3762/bjnano.9.143

• Majorana island consists of a one-dimensional topological superconductor such as a nanowire–superconductor hybrid structure and a ferromagnetic chain, with zero-energy Majorana bound states at the ends of the system. The wave functions of the two Majorana bound states overlap with each other, inducing an

Interplay between pairing and correlations in spin-polarized bound states

• Szczepan Głodzik,
• Aksel Kobiałka,
• Anna Gorczyca-Goraj,
• Andrzej Ptok,
• Grzegorz Górski,
• Maciej M. Maśka and
• Tadeusz Domański

Beilstein J. Nanotechnol. 2018, 9, 1370–1380, doi:10.3762/bjnano.9.129

• the Kondo and the leaking Majorana quasiparticle can be confronted with each other. These magnetically polarized YSR and Majorana quasiparticles as well as the subgap Kondo effect can be experimentally verified using tunneling heterostructures with ferromagnetic lead (STM tip). Results and Discussion

Proximity effect in a two-dimensional electron gas coupled to a thin superconducting layer

• Christopher Reeg,
• Daniel Loss and
• Jelena Klinovaja

Beilstein J. Nanotechnol. 2018, 9, 1263–1271, doi:10.3762/bjnano.9.118

• proposals to realize topological superconductivity that have received the most attention to date involve engineering Majorana bound states in either low-dimensional semiconducting systems [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] or in ferromagnetic atomic chains [24][25][26

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

• for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 106, India 10.3762/bjnano.9.104 Abstract Ferromagnetic antidot arrays have emerged as a system of tremendous interest due to their interesting spin configuration and dynamics as well as their potential applications in magnetic storage

• triangular holes in future magnonic and spintronic devices. Keywords: ferromagnetic antidot lattice; magnonic crystal; micromagnetic simulations; spin-wave modes; time-resolved magneto-optical Kerr effect; Introduction Recent advances in nanofabrication techniques have resulted in artificially patterned

• magnetic metamaterials, known as magnonic crystals (MCs), which have great potential for technological applications and fundamental research [1][2]. Investigation and tailoring of the magnetization dynamics in ferromagnetic nanodots [3][4], nanowires [5] and antidots [6][7][8] have fuelled considerable

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

• -prepared samples compared to the annealed samples and to the formation of a bulk-like ferromagnetic core and a shell composed of disordered moments [32][34][53]. The temperature dependence of the saturation magnetization of the annealed samples prepared by both filling routes indicated a change of less

• shielded by the carbon shell. To be specific, the presence of oxide layers would imply the presence of an antiferromagnetic shell around the ferromagnetic cores, i.e., the material would evolve the exchange bias effect where nanoparticles cooled under a magnetic field show a significant shift between the

Effect of ferroelectric BaTiO₃ particles on the threshold voltage of a smectic A liquid crystal

• Abbas R. Imamaliyev,
• Mahammadali A. Ramazanov and
• Shirkhan A. Humbatov

Beilstein J. Nanotechnol. 2018, 9, 824–828, doi:10.3762/bjnano.9.76

• of other functional materials. In polymer-dispersed LCs used in flexible displays, small drops of LC are distributed in a polymer medium [5]. In colloidal LC composites, vice versa, micrometer- or submicrometer-sized particles of various nature (e.g., ferromagnetic or ferroelectric) are dispersed in

Anchoring Fe₃O₄ nanoparticles in a reduced graphene oxide aerogel matrix via polydopamine coating

• Błażej Scheibe,
• Radosław Mrówczyński,
• Natalia Michalak,
• Karol Załęski,
• Michał Matczak,
• Mateusz Kempiński,
• Zuzanna Pietralik,
• Mikołaj Lewandowski,
• Stefan Jurga and
• Feliks Stobiecki

Beilstein J. Nanotechnol. 2018, 9, 591–601, doi:10.3762/bjnano.9.55

• ][34], gas sensors [18] or even nanoswitches/actuators [22]. The magnetic properties of hybrid aerogels are related to the presence of magnetic nanoparticles (MNPs) which can be in ferromagnetic or superparamagnetic state and are embedded in aerogel matrix. Iron oxide nanoparticles, such as magnetite

• sheets [11][16][18][33][34]. This method is based on a simple single-step process; however, its main drawback is the lack of the control over nanoparticle synthesis. Therefore, as prepared iron oxide MNPs are often agglomerated (form ferromagnetic agglomerates) and heterogeneous in size and shape. The

Revealing the interference effect of Majorana fermions in a topological Josephson junction

• Jie Liu,
• Tiantian Yu and
• Juntao Song

Beilstein J. Nanotechnol. 2018, 9, 520–529, doi:10.3762/bjnano.9.50

• experimentally is related to ferromagnetic atomic chains, which are put on a trivial superconductor [15]. It is believed that MFs can generate a zero-bias conductance peak (ZBP) in the conductance spectrum [16][17][18][19], and indeed the signature of ZBPs has been observed in both systems in tunneling

Atomic layer deposition and properties of ZrO₂/Fe₂O₃ thin films

• Kristjan Kalam,
• Helina Seemen,
• Peeter Ritslaid,
• Mihkel Rähn,
• Aile Tamm,
• Kaupo Kukli,
• Aarne Kasikov,
• Joosep Link,
• Raivo Stern,
• Salvador Dueñas,
• Helena Castán and
• Héctor García

Beilstein J. Nanotechnol. 2018, 9, 119–128, doi:10.3762/bjnano.9.14

• processes have been employed to prepare the samples. Ca- and Mg-stabilized cubic zirconia, prepared by pulsed laser deposition (PLD), has shown ferromagnetic properties [3]. Magnetic properties of PLD-synthesized ZrO2, doped with Co, Fe, Mn or Ni, have been studied [4], showing that doping ZrO2 with Mn

• properties were characterized [5]. Upon annealing at 500 °C, the metastable cubic phase of ZrO2 was stabilized and ferromagnetic hysteresis of the nanocomposite film was confirmed. Saturation magnetization was measured to be ≈173 emu/g [5]. Undoped ZrO2, prepared by pulsed electron beam deposition [6] or

• reactive DC magnetron sputtering [7], also exhibited ferromagnetic properties. The undoped ZrO2 exhibited ferromagnetic properties mainly driven by oxygen vacancies. Monoclinic and tetragonal phases with similar amounts of oxygen vacancies were compared and ferromagnetism was only observed in the case of

Comparative study of post-growth annealing of Cu(hfac)₂, Co₂(CO)₈ and Me₂Au(acac) metal precursors deposited by FEBID

• Marcos V. Puydinger dos Santos,
• Aleksandra Szkudlarek,
• Artur Rydosz,
• Carlos Guerra-Nuñez,
• Fanny Béron,
• Kleber R. Pirota,
• Stanislav Moshkalev,
• José Alexandre Diniz and
• Ivo Utke

Beilstein J. Nanotechnol. 2018, 9, 91–101, doi:10.3762/bjnano.9.11

• ], ferromagnetic nanostructures for magnetic logic and memory [23][24][25], as well as functional core–shell ferromagnetic nanowires with improved magnetic properties [26] have already been realised through this technique. It is worth mentioning that the superior conductivity of Cu, compared to other non-noble

• -based devices [28]. Furthermore, the possibility of depositing 3D nanostructures with high aspect ratio makes FEBID an adequate tool for the fabrication of advanced scanning-probe systems, as well as high-resolution ferromagnetic probes for magnetic force microscopy (MFM) [29][30][31]. Nevertheless, the

Magnetic field induced orientational transitions in liquid crystals doped with carbon nanotubes

• Danil A. Petrov,
• Pavel K. Skokov and
• Alexander N. Zakhlevnykh

Beilstein J. Nanotechnol. 2017, 8, 2807–2817, doi:10.3762/bjnano.8.280

• researchers [1]. This is not only because liquid crystals (LCs) have found wide application in modern optoelectronic devices [2] but also because anisometric particles orient like a LC in a medium that is capable of spontaneous orientational ordering. Examples of such media are suspensions of ferromagnetic or

• ferroelectric particles, as well as of carbon nanotubes. In 1970, Brochard and de Gennes proposed to dope nematic liquid crystals (NLCs) with elongated ferromagnetic particles [3]. The magnetic susceptibility of such composite system (called ferronematic), turned out to be several orders of magnitude higher

• ferronematics have been published [4][5], which indicates the interest in this kind of composite materials. Along with ferri- or ferromagnetic particles it is also possible to use carbon nanotubes (CNTs) in order to increase the magneto-orientational response of the LC matrix [6][7]. Due to the highly elongated

Dry adhesives from carbon nanofibers grown in an open ethanol flame

• Christian Lutz,
• Julia Syurik,
• C. N. Shyam Kumar,
• Christian Kübel,
• Michael Bruns and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2017, 8, 2719–2728, doi:10.3762/bjnano.8.271

• () acting away from the magnet. In principle there is a ferromagnetic force acting on the Ni catalysts below the Curie temperature of Nickel (360 °C). The temperature of the ethanol flame, however, is about 750 °C. Consequently, only a small paramagnetic force might act on the Ni catalysts () and the

• temperature a ferromagnetic or paramagnetic force acts on the Ni catalysts. Since the temperature of 750 °C in the ethanol flame is considerably higher than the Curie temperature of Ni (360 °C) only a small paramagnetic force acts on the Ni catalysts () in the direction towards the magnet. Consequently, as

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

• [82]. SFQ-to-current conversion can be realized also by superconducting–ferromagnetic transistors (SFTs) [83] or by “non-Josephson” devices such as an n-Tron [84]. The former is a three (or four) -terminal device comprising two stacked Josephson junctions. One of them, the “injector”, (containing

• ferromagnetic layer(s)) serves for injection of spin-polarized electrons in a common superconducting electrode of both junctions, thus suppressing its superconductivity. This manifests itself as redistribution of the superconducting current flowing through this electrode or as degradation of the critical

Ferrocholesteric–ferronematic transitions induced by shear flow and magnetic field

• Dmitriy V. Makarov,
• Alexander A. Novikov and
• Alexander N. Zakhlevnykh

Beilstein J. Nanotechnol. 2017, 8, 2552–2561, doi:10.3762/bjnano.8.255

• ; helix unwinding; liquid crystals; magnetic field; shear flow; Introduction The dispersing of nanoparticles of different nature (e.g., carbon nanotubes, ferromagnetic or ferroelectric particles, quantum dots, silica particles) into liquid crystals (LCs) leads to a change in the properties of the

• mechanism of interaction between the LC and an external magnetic field, the addition of magnetic particles into the LC leads to the appearance of an additional dipole mechanism of the influence on the system. Some types of synthesized ferroliquid crystals have ferromagnetic properties and are highly

• transition field Hc = πHq/2 [13]. A comparison of the elastic F1 and ferromagnetic F3 contributions determines one more typical field , which corresponds to the ferrocholesteric–ferronematic transition field with the predominance of the dipole mechanism of the magnetic field effect over the quadrupole

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

• and only a small distortion angle of the liquid crystal molecular director is observed. A comparison with a previously developed theoretical model confirms this small deviation. Keywords: ferromagnetic nanoparticles; Fréedericksz transition; Introduction Currently, there is a high interest in the

• theoretical analysis of suspensions of ferromagnetic particles in water, the so-called ferrofluids [1], or in liquid crystals [2][3][4][5][6][7][8], as well as in related experimental studies [9][10]. Optical phase modulation can be easily achieved in nematic liquid crystals (LC) subjected to external fields

• reason is the long response time of liquid crystals to the field action. The second reason is the high threshold for the Fréedericksz transition, which requires powerful DC voltage sources and large electromagnets. By using ferromagnetic particles, the response time can be reduced, but at the cost of a

Towards molecular spintronics

• Georgeta Salvan and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2017, 8, 2464–2466, doi:10.3762/bjnano.8.245

• guests with topics beyond the molecular systems investigated in our Research Unit, for example: theoretical predictions on metal/C60 interfaces [16], magneto-resistive donor/acceptor transistors [17], spin-crossover complexes [18], ferromagnetic thin films obtained from organic blends [19], and

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

• reports on Co-FEBID, which have confirmed this layer to be non-ferromagnetic [50]. Furthermore, a thin layer containing carbon and oxygen of about 7 nm is formed due to contamination before and during the electron beam irradiation in the TEM experiment. As a result, the average diameter of cobalt under

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

• ferromagnetic Fe thin film exhibits pronounced spin dependence. These investigations suggest the possibility of versatile applications in spintronic devices. The calculations on model systems with gold contacts show that it is possible to obtain spin-polarized currents from both phthalocyanine-based devices