The Experts below are selected from a list of 15 Experts worldwide ranked by ideXlab platform

N. V. Sharenkova - One of the best experts on this subject based on the ideXlab platform.

  • Magnetic Properties of Fullerene–Thermally Exfoliated Graphite Composites Doped with Sodium
    Physics of the Solid State, 2019
    Co-Authors: V. I. Berezkin, V. V. Popov, S. V. Kidalov, N. V. Sharenkova
    Abstract:

    The Magnetic properties (field range H = 0–50 kOe, temperature range T = 3–300 K), and structural features of a sodium-doped carbon composite material based on fullerene C_60 and thermally exfoliated graphite (TEG) are studied. The material is obtained with different ratios of the components by sintering at a pressure of 7 GPa and T = 600°C, at which it is found that significant amorphization of the crystal lattice of the initial C_60 occurs. The dia-, para-, and ferroMagnetic components ( M _D, M _PM, and M _FM) were separated from the total Magnetic Moment of the samples under study. It is found that a sodium dopant has no effect on the Magnetic properties of the composite. Analysis of the M _PM( H ) field dependences by using the Brillouin function for the fullerene-containing sample (i.e., without TEG) makes it possible to determine the quantum number of the total angular Momentum of paraMagnetic (PM) centers. Its value is found to be J = 1, which corresponds to Elementary Magnetic Moment μ_PM = 2μ_B of a PM center. The concentration of PM centers is estimated at the level of N _PM ≈ (2–5) × 10^18 g^–1 for most samples, including the material without TEG. The introduction of TEG into the initial composition and an increase in its proportion in the composite leads to a strong increase in the Magnetic Moment, which is explained by an increase in both the J value and the concentration of PM centers.

V. I. Berezkin - One of the best experts on this subject based on the ideXlab platform.

  • Magnetic Properties of Fullerene–Thermally Exfoliated Graphite Composites Doped with Sodium
    Physics of the Solid State, 2019
    Co-Authors: V. I. Berezkin, V. V. Popov, S. V. Kidalov, N. V. Sharenkova
    Abstract:

    The Magnetic properties (field range H = 0–50 kOe, temperature range T = 3–300 K), and structural features of a sodium-doped carbon composite material based on fullerene C_60 and thermally exfoliated graphite (TEG) are studied. The material is obtained with different ratios of the components by sintering at a pressure of 7 GPa and T = 600°C, at which it is found that significant amorphization of the crystal lattice of the initial C_60 occurs. The dia-, para-, and ferroMagnetic components ( M _D, M _PM, and M _FM) were separated from the total Magnetic Moment of the samples under study. It is found that a sodium dopant has no effect on the Magnetic properties of the composite. Analysis of the M _PM( H ) field dependences by using the Brillouin function for the fullerene-containing sample (i.e., without TEG) makes it possible to determine the quantum number of the total angular Momentum of paraMagnetic (PM) centers. Its value is found to be J = 1, which corresponds to Elementary Magnetic Moment μ_PM = 2μ_B of a PM center. The concentration of PM centers is estimated at the level of N _PM ≈ (2–5) × 10^18 g^–1 for most samples, including the material without TEG. The introduction of TEG into the initial composition and an increase in its proportion in the composite leads to a strong increase in the Magnetic Moment, which is explained by an increase in both the J value and the concentration of PM centers.

S. V. Kidalov - One of the best experts on this subject based on the ideXlab platform.

  • Magnetic Properties of Fullerene–Thermally Exfoliated Graphite Composites Doped with Sodium
    Physics of the Solid State, 2019
    Co-Authors: V. I. Berezkin, V. V. Popov, S. V. Kidalov, N. V. Sharenkova
    Abstract:

    The Magnetic properties (field range H = 0–50 kOe, temperature range T = 3–300 K), and structural features of a sodium-doped carbon composite material based on fullerene C_60 and thermally exfoliated graphite (TEG) are studied. The material is obtained with different ratios of the components by sintering at a pressure of 7 GPa and T = 600°C, at which it is found that significant amorphization of the crystal lattice of the initial C_60 occurs. The dia-, para-, and ferroMagnetic components ( M _D, M _PM, and M _FM) were separated from the total Magnetic Moment of the samples under study. It is found that a sodium dopant has no effect on the Magnetic properties of the composite. Analysis of the M _PM( H ) field dependences by using the Brillouin function for the fullerene-containing sample (i.e., without TEG) makes it possible to determine the quantum number of the total angular Momentum of paraMagnetic (PM) centers. Its value is found to be J = 1, which corresponds to Elementary Magnetic Moment μ_PM = 2μ_B of a PM center. The concentration of PM centers is estimated at the level of N _PM ≈ (2–5) × 10^18 g^–1 for most samples, including the material without TEG. The introduction of TEG into the initial composition and an increase in its proportion in the composite leads to a strong increase in the Magnetic Moment, which is explained by an increase in both the J value and the concentration of PM centers.

V. V. Popov - One of the best experts on this subject based on the ideXlab platform.

  • Magnetic Properties of Fullerene–Thermally Exfoliated Graphite Composites Doped with Sodium
    Physics of the Solid State, 2019
    Co-Authors: V. I. Berezkin, V. V. Popov, S. V. Kidalov, N. V. Sharenkova
    Abstract:

    The Magnetic properties (field range H = 0–50 kOe, temperature range T = 3–300 K), and structural features of a sodium-doped carbon composite material based on fullerene C_60 and thermally exfoliated graphite (TEG) are studied. The material is obtained with different ratios of the components by sintering at a pressure of 7 GPa and T = 600°C, at which it is found that significant amorphization of the crystal lattice of the initial C_60 occurs. The dia-, para-, and ferroMagnetic components ( M _D, M _PM, and M _FM) were separated from the total Magnetic Moment of the samples under study. It is found that a sodium dopant has no effect on the Magnetic properties of the composite. Analysis of the M _PM( H ) field dependences by using the Brillouin function for the fullerene-containing sample (i.e., without TEG) makes it possible to determine the quantum number of the total angular Momentum of paraMagnetic (PM) centers. Its value is found to be J = 1, which corresponds to Elementary Magnetic Moment μ_PM = 2μ_B of a PM center. The concentration of PM centers is estimated at the level of N _PM ≈ (2–5) × 10^18 g^–1 for most samples, including the material without TEG. The introduction of TEG into the initial composition and an increase in its proportion in the composite leads to a strong increase in the Magnetic Moment, which is explained by an increase in both the J value and the concentration of PM centers.

Antonio Vettoliere - One of the best experts on this subject based on the ideXlab platform.

  • Modelled Spin Sensitivity of nanoSQUIDs in Different Configurations
    IEEE Transactions on Applied Superconductivity, 2018
    Co-Authors: Carmine Granata, Paolo Silvestrini, Berardo Ruggiero, Antonio Vettoliere
    Abstract:

    Micro- and nano-sized superconducting quantum interference devices (SQUIDs) allow the measurements of extremely low Magnetic Moment. In the last decade, many efforts have been devoted to the study and the development of these quantum sensors at a nanometric scale (nanoSQUIDs). In this paper, a study of performance of these nanosensors in different configurations is presented. In particular, the Magnetic flux coupling and the spin sensitivity have been computed for planar nanoSQUIDs in square and rectangular shapes in the presence of an Elementary Magnetic Moment (Bohr magneton). The computation has been carried out as a function of the position of the Bohr magneton within the sensitive SQUID loop and for different distances from the loop plane. The same characteristics have also been computed for a square nanoSQUID as a function of side length taking into account the increase of the Magnetic flux noise as a function of the loop inductance. In addition, a configuration including a nonflat geometry has been analyzed.

  • Nano Superconducting Quantum Interference device: A powerful tool for nanoscale investigations
    Physics Reports, 2016
    Co-Authors: Carmine Granata, Antonio Vettoliere
    Abstract:

    Abstract The Magnetic sensing at nanoscale level is a promising and interesting research topic of nanoscience. Indeed, Magnetic imaging is a powerful tool for probing biological, chemical and physical systems. The study of small spin cluster, like Magnetic molecules and nanoparticles, single electron, cold atom clouds, is one of the most stimulating challenges of applied and basic research of the next years. In particular, the Magnetic nanoparticle investigation plays a fundamental role for the modern material science and its relative technological applications like ferrofluids, Magnetic refrigeration and biomedical applications, including drug delivery, hyper-thermia cancer treatment and Magnetic resonance imaging contrast-agent. Actually, one of the most ambitious goals of the high sensitivity magnetometry is the detection of Elementary Magnetic Moment or spin. In this framework, several efforts have been devoted to the development of a high sensitivity Magnetic nanosensor pushing sensing capability to the individual spin level. Among the different Magnetic sensors, Superconducting QUantum Interference Devices (SQUIDs) exhibit an ultra high sensitivity and are widely employed in numerous applications. Basically, a SQUID consists of a superconducting ring (sensitive area) interrupted by two Josephson junctions. In the recent years, it has been proved that the Magnetic response of nano-objects can be effectively measured by using a SQUID with a very small sensitive area (nanoSQUID). In fact, the sensor noise, expressed in terms of the Elementary Magnetic Moment (spin or Bohr magneton), is linearly dependent on the SQUID loop side length. For this reason, SQUIDs have been progressively miniaturized in order to improve the sensitivity up to few spin per unit of bandwidth. With respect to other techniques, nanoSQUIDs offer the advantage of direct measurement of magnetization changes in small spin systems. In this review, we focus on nanoSQUIDs and its applications. In particular, we will discuss the motivations, the theoretical aspects, the fabrication techniques, the different nanoSQUIDs and the relative nanoscale applications.