Modulated critical currents of spin-transfer torque-induced resistance changes in NiCu/Cu multilayered nanowires

• Mengqi Fu,
• Roman Hartmann,
• Julian Braun,
• Sergej Andreev,
• Torsten Pietsch and
• Elke Scheer

Beilstein J. Nanotechnol. 2024, 15, 360–366, doi:10.3762/bjnano.15.32

• oscillatory manner by the magnetic field in the nanowire-based devices. We present a toy model to qualitatively explain these observations. Keywords: AAO template; critical current; multilayered magnetic nanowires; spin-transfer torque; three-dimensional devices; Introduction Spin-transfer torque (STT) has

• a nonmonotonic dependence between the critical current of STT-assisted resistance changes and the strength of the external magnetic field in NiCu/Cu multilayered nanowire devices with arbitrary sequence of magnetic and nonmagnetic sections along the long axis of the nanowires. The STT devices were

• at a positive critical current Ic+ of 1.5 mA in the upsweep of I (initiating from a large negative current) and an abrupt jump at a negative critical current Ic− of around −1.2 mA in the downsweep of I (starting from a large positive current), thereby forming a hysteresis loop. The hysteresis loop

Design, fabrication, and characterization of kinetic-inductive force sensors for scanning probe applications

• August K. Roos,
• Ermes Scarano,
• Elisabet K. Arvidsson,
• Erik Holmgren and
• David B. Haviland

Beilstein J. Nanotechnol. 2024, 15, 242–255, doi:10.3762/bjnano.15.23

• through the inductor is limited by the critical current Ic, also set by material choice and physical dimensions. From Equation 5, we can increase nc for a given material by, again, making the nanowire longer or narrower, or by increasing Lk,□ through a thinner film. However, longer and narrower nanowires

• kinetic inductance of the nanowire. In our design, a sufficient requirement on g0 is that the motional sidebands due to the thermal noise force can be resolved above the noise floor of the detector. We prioritize a larger critical current of the nanowire to compensate a potentially smaller g0. For

• with minimal back-action from motion detection. Our design covers a vast parameter space, balancing different considerations for both the electrical mode, such as critical current Ic, critical temperature Tc, and kinetic inductance per square Lk,□, and the mechanical mode, such as resonance frequency

Josephson dynamics and Shapiro steps at high transmissions: current bias regime

• Artem V. Galaktionov and
• Andrei D. Zaikin

Beilstein J. Nanotechnol. 2024, 15, 51–56, doi:10.3762/bjnano.15.5

• reconsidered. Recently, it was demonstrated [3] that provided the voltage changes adiabatically and remains small enough, that is, V(t) ≪ Δ/e, the voltage dynamics in the current bias regime can be described by a simple equation, where Ic = πΔ/(eRN) is the critical current of our weak link at T → 0 and φ(t

Measurements of dichroic bow-tie antenna arrays with integrated cold-electron bolometers using YBCO oscillators

• Leonid S. Revin,
• Dmitry A. Pimanov,
• Alexander V. Chiginev,
• Anton V. Blagodatkin,
• Viktor O. Zbrozhek,
• Andrey V. Samartsev,
• Anastasia N. Orlova,
• Dmitry V. Masterov,
• Alexey E. Parafin,
• Victoria Yu. Safonova,
• Anna V. Gordeeva,
• Andrey L. Pankratov,
• Leonid S. Kuzmin,
• Anatolie S. Sidorenko,
• Silvia Masi and
• Paolo de Bernardis

Beilstein J. Nanotechnol. 2024, 15, 26–36, doi:10.3762/bjnano.15.3

• deposition of cerium dioxide CeO2 on the heated substrate as a buffer layer. The dimensions of the obtained Josephson junctions were 50 µm in length and 0.3 µm in thickness. At a temperature T ~ 2.7 K, the value of the critical current density was ~400 kA/cm2 with the ICRN product of ~1.6 mV. The junctions

A bifunctional superconducting cell as flux qubit and neuron

• Dmitrii S. Pashin,
• Pavel V. Pikunov,
• Marina V. Bastrakova,
• Andrey E. Schegolev,
• Nikolay V. Klenov and
• Igor I. Soloviev

Beilstein J. Nanotechnol. 2023, 14, 1116–1126, doi:10.3762/bjnano.14.92

• by the second term in Equation 1, wherein the effective coordinate is a phase of the Josephson junction, φ. The quantities Ec = and EJ = are the capacitive and the Josephson energy, respectively, determined by critical current Ic and the capacity C of the Josephson junction. A typical example of

A distributed active patch antenna model of a Josephson oscillator

• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2023, 14, 151–164, doi:10.3762/bjnano.14.16

• density through the JJ, which has Cooper pair and quasiparticle (QP) components, Here, Jc0 is the Josephson critical current density, η is the Josephson phase difference, and rQP = RQPab is the QP resistance per unit area. Active patch antenna model of a junction Equation 1 is the equation for an active

• geometrical resonances, the dc current, well above the field-dependent critical current, I ≫ Ic(H), is determined by the QP resistance, I = V/RQP. In dimensionless units, I/Ic0 = αV/Vp, where Vp = Φ0ωp/2π is the voltage at plasma frequency. At resonances, a partial rectification of the oscillating

Observation of collective excitation of surface plasmon resonances in large Josephson junction arrays

• Roger Cattaneo,
• Mikhail A. Galin and
• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2022, 13, 1578–1588, doi:10.3762/bjnano.13.132

• of different voltage states at the same current. This will be exploited for accessing a larger variety of states with different number of active junctions in the oscillating resistive state. Figure 2a shows the modulation, Ic(H), of the critical current versus the in-plane magnetic field for the

• steps with the only difference that the corresponding MW current, IMW, originates from the cavity mode in the array rather than from an external source. Therefore, the amplitude of the step, ΔI, is proportional to the critical current and modulates together with it as a function of magnetic field, as

• are done in zero magnetic field at T ≃ 2.6 K. Appearance of profound steps in the I–Vs due to excitation of cavity resonances in electrodes is clearly seen for both arrays. (a) Fraunhofer-type modulation of the critical current as a function of in-plane magnetic field for the linear array. Panels (b–d

Induced electric conductivity in organic polymers

• Konstantin Y. Arutyunov,
• Anatoli S. Gurski,
• Vladimir V. Artemov,
• Alexander L. Vasiliev,
• Azat R. Yusupov,
• Danfis D. Karamov and
• Alexei N. Lachinov

Beilstein J. Nanotechnol. 2022, 13, 1551–1557, doi:10.3762/bjnano.13.128

• only during the process of sample preparation for transmission microscopy. The sufficiently high critical current (Figure 4b–d) also indicates the large area of the conductive channel, which does not correspond to the scenario of the occurrence of single point short circuits. The I–V dependencies of

Coherent amplification of radiation from two phase-locked Josephson junction arrays

• Mikhail A. Galin,
• Vladimir M. Krasnov,
• Ilya A. Shereshevsky,
• Nadezhda K. Vdovicheva and
• Vladislav V. Kurin

Beilstein J. Nanotechnol. 2022, 13, 1445–1457, doi:10.3762/bjnano.13.119

• estimated as ≃300 V/W. Results Figure 2a shows the individually measured IVCs of array-a and array-b of sample-1 (Figure 1a,b). The critical current in both arrays is Ic = 2.0–2.1 mA and the characteristic frequency, estimated within the resistively shunted junction (RSJ) model, is in the range of fc ∼ 100

• –120 GHz. Figure 2b shows similar data for sample-2. Here, for both arrays, Ic ≈ 2.9 mA and fc ∼ 80–100 GHz. Although the area of junctions in sample-2 is smaller, the critical current is slightly larger than in sample-1 due to higher doping of the NbSi interlayers. Note that the abrupt transition from

Density of states in the presence of spin-dependent scattering in SF bilayers: a numerical and analytical approach

• Tairzhan Karabassov,
• Valeriia D. Pashkovskaia,
• Nikita A. Parkhomenko,
• Anastasia V. Guravova,
• Elena A. Kazakova,
• Boris G. Lvov,
• Alexander A. Golubov and
• Andrey S. Vasenko

Beilstein J. Nanotechnol. 2022, 13, 1418–1431, doi:10.3762/bjnano.13.117

• patterns on the surface of a 3D topological insulator (TI) [18]. The Josephson critical current demonstrates damped oscillatory behavior as a function of the thickness of the ferromagnetic layer in SFS Josephson junctions [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39

Nonlinear features of the superconductor–ferromagnet–superconductor φ₀ Josephson junction in the ferromagnetic resonance region

• Aliasghar Janalizadeh,
• Ilhom R. Rahmonov,
• Sara A. Abdelmoneim,
• Yury M. Shukrinov and
• Mohammad R. Kolahchi

Beilstein J. Nanotechnol. 2022, 13, 1155–1166, doi:10.3762/bjnano.13.97

• ) = EJ[1 − cos(φ − φ0)], and EJ = Φ0Ic/2π is the Josephson energy. Here Φ0 is the flux quantum, Ic is the critical current, r = lυso/υF, l = 4hL/ℏυF, L is the length of the ferromagnetic (F) layer, h is the exchange field of the F layer, , the parameter υso/υF characterizes a relative strength of spin

• critical current Ic and the voltage V is normalized to Vc = IcR. The system in Equation 6 is solved numerically using the fourth-order Runge–Kutta method [14]. Results and Discussion A. Effect of system parameters on the anomalous damping dependence ADD of the FMR frequency with increasing α was discussed

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

• ]. Moreover, attempts have been made to use this material (with low iron concentrations of x = 0.01–0.03) for MJJ memory applications [1][14][15][24][31][32]. However, these studies faced the problems of small critical current and temporal instability of magnetic properties [33]. On the one hand, nanoscale

• inhomogeneities cause spin-flip and pairing wave function damping, thus, reducing the magnitude of the Josephson critical current. Small-scale inhomogeneities are difficult to detect with either conventional neutron-scattering methods [34] or with the stationary magneto-optical Kerr/Faraday effect and

A superconducting adiabatic neuron in a quantum regime

• Marina V. Bastrakova,
• Dmitrii S. Pashin,
• Dmitriy A. Rybin,
• Andrey E. Schegolev,
• Nikolay V. Klenov,
• Igor I. Soloviev,
• Anastasiya A. Gorchavkina and
• Arkady M. Satanin

Beilstein J. Nanotechnol. 2022, 13, 653–665, doi:10.3762/bjnano.13.57

• in [46] when considering the classical mode of this system. Inductances are normalized to (2πIc/Φ0), where Ic is the critical current of the Josephson junction and Φ0 is the magnetic flux quantum. The inertial properties of the system are due to the junction capacitance, which, along with the

• critical current Ic, determines the plasma frequency of the JJ, In this case, the dissipative properties of the system are determined by the Josephson characteristic frequency ωc = 2eRIcℏ (here, R and C are the normal state resistance and capacitance of the Josephson junction, respectively). Dynamic

Approaching microwave photon sensitivity with Al Josephson junctions

• Andrey L. Pankratov,
• Anna V. Gordeeva,
• Leonid S. Revin,
• Dmitry A. Ladeynov,
• Anton A. Yablokov and
• Leonid S. Kuzmin

Beilstein J. Nanotechnol. 2022, 13, 582–589, doi:10.3762/bjnano.13.50

• power, whose presence can be observed only in the switching distributions and in the shorter lifetime of the superconducting state. The used experimental setup is the same as in [7], except for the measured sample. In [7], the critical current of the sample was very low, and the phase diffusion regime

• was noticeably pronounced. The sample considered here has a much higher critical current, and the phase diffusion does not appear. As a result, the theoretical estimates based on the BCS theory for critical currents and Kramers’ theory for escape times are well applicable. Furthermore, the analysis of

• switching probability, respectively. We begin our consideration of the Josephson junction as a photon counter with its current–voltage characteristic (see Figure 2a) and the determination of the critical current. All further analysis of experimental results and understanding of the energy relations of the

Tunable superconducting neurons for networks based on radial basis functions

• Andrey E. Schegolev,
• Nikolay V. Klenov,
• Sergey V. Bakurskiy,
• Igor I. Soloviev,
• Mikhail Yu. Kupriyanov,
• Maxim V. Tereshonok and
• Anatoli S. Sidorenko

Beilstein J. Nanotechnol. 2022, 13, 444–454, doi:10.3762/bjnano.13.37

• the flux quantum Φ0; currents are normalized to the critical current of the Josephson junctions IC; inductances are normalized to the characteristic inductance 2πLIC/Φ0, times are normalised to the characteristic time tC = Φ0/(2πVC) (VC is the characteristic voltage of a Josephson junction). Equations

• and parametric amplifiers. But these devices use nonlinear properties of thin superconducting films at large values of carrying currents comparable to the critical current. However, for our purposes, linear inductors are required. So we consider only the case of a small current in comparison with the

• , normalised to the characteristic energy E0 = Φ0IC/2π, as function of the rise/fall time of the input signal for different bias fluxes: φb = {0.01, 0.05, 0.1}π. The insert demonstrates the form of temporal dynamic for input flux and dissipation. If the critical current for Josephson junctions IC is equal to

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

• degrees of freedom to control the critical current of MJJs [10] or SSVs [6], or current–phase relations in MJJs [11][12]. In particular, the spin-valve structure embedded into a MJJ can serve as an actuator for switching the MJJ between critical current modes or flipping its current–phase relation, thus

A broadband detector based on series YBCO grain boundary Josephson junctions

• Egor I. Glushkov,
• Alexander V. Chiginev,
• Leonid S. Kuzmin and
• Leonid S. Revin

Beilstein J. Nanotechnol. 2022, 13, 325–333, doi:10.3762/bjnano.13.27

• of the power received by the antenna is absorbed in a particular JJ (according to Table 1). In Equation 2, the first three terms on the right represent, respectively, the displacement current, the normal current, and the supercurrent with junction critical current Ic, capacitance C, and normal

• operating point near the critical current (dashed line) is selected for broadband detection. The response is determined by the voltage, which increases with increasing power until it reaches the voltage at the Shapiro step. For this regime, the use of serial JJs can be beneficial since the total voltage

• of magnitude [34][35]. It does not take into account the increase in output noise due to the influence of low-frequency noise spectra of the critical current fluctuations δIc and normal resistance fluctuations δRN associated with the transport mechanisms of the Cooper pairs and quasiparticles

Design aspects of Bi₂Sr₂CaCu₂O_8+δ THz sources: optimization of thermal and radiative properties

• Mikhail M. Krasnov,
• Natalia D. Novikova,
• Roger Cattaneo,
• Alexey A. Kalenyuk and
• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2021, 12, 1392–1403, doi:10.3762/bjnano.12.103

• multiple branches due to one-by-one switching of IJJs from the superconducting to the resistive state. The are N ≈ 200 and ≈300 IJJs in whisker and crystal mesas, respectively. Both the whisker and the crystal have a similar suppressed Tc ≈ 65–70 K and low critical current densities of IJJs, Jc ≈ 100 A/cm2

Nonmonotonous temperature dependence of Shapiro steps in YBCO grain boundary junctions

• Leonid S. Revin,
• Dmitriy V. Masterov,
• Alexey E. Parafin,
• Sergey A. Pavlov and
• Andrey L. Pankratov

Beilstein J. Nanotechnol. 2021, 12, 1279–1285, doi:10.3762/bjnano.12.95

• are in agreement with the calculations based on the resistively–capacitively shunted junction model and Bessel theory. The emergence of the receiving optima is explained by the mutual influence of the varying critical current and the characteristic frequency. Keywords: characteristic frequency

• -probe technique. In the RCSJ model to which we compare our experimental results, the junction phase ϕ with an ideal critical current Ic, a resistance RN and a capacitance C are described by the stochastic differential equation [32][33] where the voltage V = dϕ/dt × 2π/Φ0 (Φ0 is the magnetic flux quantum

• depends on the characteristic frequency ωc = 2eIcRN/ℏ of the JJ. Results First, the current–voltage characteristics (IVCs) were measured, and the value of the critical current as a function of temperature was found, see Figure 1. The Ic(T) dependence is similar to the experimental observations for other

Functional nanostructures for electronics, spintronics and sensors

• Anatolie S. Sidorenko

Beilstein J. Nanotechnol. 2020, 11, 1704–1706, doi:10.3762/bjnano.11.152

• theoretically predicted and then experimentally detected. Some examples include a nonuniform superconducting Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) state, S/F π-junctions, oscillations of critical temperature and critical current in S/F hybrids on the thickness of the F-layer, multiperiodic re-entrant

Controlling the proximity effect in a Co/Nb multilayer: the properties of electronic transport

• Sergey Bakurskiy,
• Mikhail Kupriyanov,
• Nikolay V. Klenov,
• Igor Soloviev,
• Andrey Schegolev,
• Roman Morari,
• Yury Khaydukov and
• Anatoli S. Sidorenko

Beilstein J. Nanotechnol. 2020, 11, 1336–1345, doi:10.3762/bjnano.11.118

• to adjust the critical current during the functioning of a neural network [20]. In this paper, we propose a way to eliminate completely the Josephson nonlinearity from the synapse circuit. The processes of switching on and off the superconductivity in the thin s-layers, surrounded by magnetic

3D superconducting hollow nanowires with tailored diameters grown by focused He⁺ beam direct writing

• Rosa Córdoba,
• Alfonso Ibarra,
• Dominique Mailly,
• Isabel Guillamón,
• Hermann Suderow and
• José María De Teresa

Beilstein J. Nanotechnol. 2020, 11, 1198–1206, doi:10.3762/bjnano.11.104

• is present along the whole nanowire length. Moreover, these nanowires become superconducting at 6.8 K and show high values of critical magnetic field and critical current density. Consequently, these 3D nano-objects could be implemented as components in the next generation of electronics, such as

• nanopipettes, as demonstrated in 3D reconstructions of electron tomography experiments. Finally, these 3D hollow NWs exhibit superconductivity below 6.8 K (Tc), as well as high upper critical magnetic fields µ0Hc2 ≈ 14.7 T, and large critical current densities Jc ≈ 0.15 MA/cm2. Results and Discussion Growth of

Microwave photon detection by an Al Josephson junction

• Leonid S. Revin,
• Andrey L. Pankratov,
• Anna V. Gordeeva,
• Anton A. Yablokov,
• Igor V. Rakut,
• Victor O. Zbrozhek and
• Leonid S. Kuzmin

Beilstein J. Nanotechnol. 2020, 11, 960–965, doi:10.3762/bjnano.11.80

• Novgorod, Russia Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia Chalmers University of Technology, SE-41296 Gothenburg, Sweden 10.3762/bjnano.11.80 Abstract An aluminium Josephson junction (JJ), with a critical current suppressed by a factor of three compared with the maximal

• -photon counter described in [4]. We study the possibility of detecting photons in the gigahertz frequency range using an aluminium Josephson junction with a suppressed critical current. The main requirement to this counter is an extremely large lifetime (thousands of seconds), orders of magnitude larger

• than the switching time after the photon absorption (typically less than nanoseconds). In [4] it was shown theoretically that both the required sensitivity and the noise immunity can be reached at the same time in JJ with a suppressed critical current. Besides that, the mesoscopic junctions with low

A Josephson junction based on a highly disordered superconductor/low-resistivity normal metal bilayer

• Pavel M. Marychev and
• Denis Yu. Vodolazov

Beilstein J. Nanotechnol. 2020, 11, 858–865, doi:10.3762/bjnano.11.71

• layer and the length of the S constriction are about the superconducting coherence length the CPR is single-valued and can be close to a sinusoidal shape. The product IcRn can reach Δ(0)/2|e| (Ic is the critical current of the junction, Rn is its normal-state resistance, Δ(0) is the superconductor gap

• junction; Joule heating; Introduction Josephson junctions are of interest for applications such as voltage standards [1], SQUID magnetometers [2], particle detectors [3], and energy-efficient superconductor logic and memory circuits [4][5]. These applications need to have a large critical current Ic to

• are characterized by small critical current densities (significantly smaller than the depairing current density of superconducting electrodes) and a hysteretic IVC (the latter is related with the large capacitance of the insulator layer), which restricts their applicability. Elimination of hysteresis

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

• are indications of non-homogeneous, nanoclustered magnetism in Pd0.99Fe0.01 films grown on niobium [31], which may cause a shortening of the spin-memory length [32] and a reduction of the Josephson critical current. In general, the metallic Nb lattice (body-centered cubic with aNb = 329.4 pm) poorly