Analysis of magnetoresistance in arrays of connected nano-rings

We study the anisotropic magnetoresistance (AME) of a 2D periodic square array of connected permalloy rings with periodicity of 1m combining experimental and computational techniques. The computational models consists of two parts: 1) the computation of the magnetization and 2) the computation of the current density. For 1), we use standard micromagnetic methods. For 2), we start from a potential difference applied across the sample, compute the resulting electric potential , and subsequently the corresponding current density based on a uniform conductiviy. We take into account the backreaction of the magnetoresistive effects onto the current density by self-consistently computing the current density and conductivity until they converge. We compare the experimentally measured AMR insight into the characteristics of the AMR data. Finally, we demonstrate the importance of taking into account the spatial variation of the current density when computing the AMR

Self-assembly routes towards creating superconducting and magnetic arrays

Using self-assembly from colloidal suspensions of polystyrene latex spheres we prepared well-ordered templates. By electrochemical deposition of magnetic and superconducting metals in the pores of such templates highly ordered magnetic and superconducting anti-dot nano-structures with 3D architectures were created. Further developments of this template preparation method allow us to obtain dot arrays and even more complicated structures. In magnetic anti-dot arrays we observe a large increase in coercive field produced by nanoscale (50–1000nm) holes. We also find the coercive field to demonstrate an oscillatory dependence on film thickness. In magnetic dot arrays we have explored the genesis of 3D magnetic vortices and determined the critical dot size. Superconducting Pb anti-dot arrays show pronounced Little-Parks oscillations in Tc and matching effects in magnetization and magnetic susceptibility. The spherical shape of the holes results in significantly reduced pinning strength as compared to standard lithographic samples. Our results demonstrate that self-assembly template methods are emerging as a viable, low cost route to prepare sub-micron structures

Horizon - T Experiment Calibrations - Cables

An innovative detector system called Horizon-T is constructed to study Extensive Air Showers (EAS) in the energy range above 1016 eV coming from a wide range of zenith angles (0o - 85o). The system is located at Tien Shan high-altitude Science Station of Lebedev Physical Institute of the Russian Academy of Sciences at approximately 3340 meters above the sea level. The detector consists of eight charged particle detection points separated by the distance up to one kilometer as well as optical detector to view the Vavilov-Cherenkov light from the EAS. Each detector connects to the Data Acquisition system via cables. The calibration of the time delay for each cable and the signal attenuation is provided in this article

Simulation and design of the HT-KZ Ultra-high energy cosmic rays detector system for cosmic rays with energies above 1017 eV

In the field of High Energy Physics today there are several open topics left. The Higgs boson has been recently discovered, neutrino oscillations are being studied, and some hints of the dark matter have been detected as well. Another remaining mystery is the origin and the nature of the Ultra-High Energy Cosmic Rays. There is an active project at Nazarbayev University to construct the HorizonT-Kazakhstan detector system in collaboration with the Tien Shan high-altitude Science Station (TSHSS), a part of Lebedev Physical Institute of the Russian Academy of Sciences. The full R&D is underway. A significant part of this process is the simulation, testing and construction of individual particle detectors due to the requirements of robustness and high linear range of such detectors combined with low cost and long-term operations with minimal maintenance. In this paper, the latest results of the simulation activities and experiment testing of different detection components as applicable to the HorizonT-Kazakhstan requirements are presented

Piezoelectric Characteristics of LiNbO3 Thin-film Heterostructures via Piezoresponse Force Microscopy

Electro-optic LiNbO3 thin films were deposited on Si(100) and Si(111) substrates using a radio-frequency magnetron sputtering process. The piezoelectric properties of the LiNbO3 films were investigated using the scanning probe microscopy in the piezoresponse mode. The obtained results show the high degree of grains orientation in polycrystalline structure. The piezoelectric modulus (dzz) was estimated to be 16 pm/V (for LiNbO3 / Si(100)) and 22 pm/V (for LiNbO3 / Si(111)) and the polarization about of 0.37 C·m – 2. These values are larger than those reported previously for LiNbO3 films. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3366

Simulation and design of the HT-KZ Ultra-high energy cosmic rays detector system for cosmic rays with energies above 1017 eV

In the field of High Energy Physics today there are several open topics left. The Higgs boson has been recently discovered, neutrino oscillations are being studied, and some hints of the dark matter have been detected as well. Another remaining mystery is the origin and the nature of the Ultra-High Energy Cosmic Rays. There is an active project at Nazarbayev University to construct the HorizonT-Kazakhstan detector system in collaboration with the Tien Shan high-altitude Science Station (TSHSS), a part of Lebedev Physical Institute of the Russian Academy of Sciences. The full R&D is underway. A significant part of this process is the simulation, testing and construction of individual particle detectors due to the requirements of robustness and high linear range of such detectors combined with low cost and long-term operations with minimal maintenance. In this paper, the latest results of the simulation activities and experiment testing of different detection components as applicable to the HorizonT-Kazakhstan requirements are presented

Horizon-T Experiment Calibrations – MIP Signal from Scintillator and Glass Detectors

Horizon-T, a modern Extensive Air Showers (EAS) detector system, is constructed at Tien Shan high-altitude Science Station of Lebedev Physical Institute of the Russian Academy of Sciences at approximately 3340 meters above the sea level in order to study in the energy range above 1016 eV coming from a wide range of zenith angles (0o - 85o). The detector includes eight charged particle detection points and a Vavilov-Cherenkov radiation detector. Each charged particle detector response is calibrated using single MIP (minimally ionizing particle) signal. The details of this calibration are provided in this article. This note is valid for data before March 2017 and will not be updated following any detector calibration and configuration changes as a large upgrade has been implemente

Horizon-T extensive air showers detector system operations and performance

“Horizon-T” is an innovative detector system located at Tien Shan high-altitude Science Station (TSHASS) at approximately 3340 meters above the sea level. It consists of eight detection points separated by the distance up to one kilometer that can measure time characteristics of the Extensive Air Showers (EAS) and record signal shapes with time resolution of ~10 ns. It was constructed to register EAS in the energy range above 1016 eV coming from a wide range of zenith angles (0o - 85o). The system includes both the plastic scintillator particle detectors as well as the Vavilov - Cerenkov radiation detectors subsystem to observe the Cerenkov light from the EAS in the atmosphere directly. The time resolution and signal shape analysis capabilities of the detection points are used to study EAS development in the atmosphere. The development of the EAS is a process that can be studied both spatially and temporally. For the spatial part, a distributed network of detection points is required. For the time part, a signal shape must be recorded and analysed at each point with time resolution on the order of ~10 ns. In this paper, the current system description and performance level are described. Additionally, the latest data examples showing the unusual EAS examples above 1017 eV are included

Horizon-T extensive air showers detector system operations and performance

“Horizon-T” is an innovative detector system located at Tien Shan high-altitude Science Station (TSHASS) at approximately 3340 meters above the sea level. It consists of eight detection points separated by the distance up to one kilometer that can measure time characteristics of the Extensive Air Showers (EAS) and record signal shapes with time resolution of ~10 ns. It was constructed to register EAS in the energy range above 1016 eV coming from a wide range of zenith angles (0o - 85o). The system includes both the plastic scintillator particle detectors as well as the Vavilov - Cerenkov radiation detectors subsystem to observe the Cerenkov light from the EAS in the atmosphere directly. The time resolution and signal shape analysis capabilities of the detection points are used to study EAS development in the atmosphere. The development of the EAS is a process that can be studied both spatially and temporally. For the spatial part, a distributed network of detection points is required. For the time part, a signal shape must be recorded and analysed at each point with time resolution on the order of ~10 ns. In this paper, the current system description and performance level are described. Additionally, the latest data examples showing the unusual EAS examples above 1017 eV are included

Coronal Shock Waves, EUV waves, and Their Relation to CMEs. I. Reconciliation of "EIT waves", Type II Radio Bursts, and Leading Edges of CMEs

We show examples of excitation of coronal waves by flare-related abrupt eruptions of magnetic rope structures. The waves presumably rapidly steepened into shocks and freely propagated afterwards like decelerating blast waves that showed up as Moreton waves and EUV waves. We propose a simple quantitative description for such shock waves to reconcile their observed propagation with drift rates of metric type II bursts and kinematics of leading edges of coronal mass ejections (CMEs). Taking account of different plasma density falloffs for propagation of a wave up and along the solar surface, we demonstrate a close correspondence between drift rates of type II bursts and speeds of EUV waves, Moreton waves, and CMEs observed in a few known events.Comment: 30 pages, 15 figures. Solar Physics, published online. The final publication is available at http://www.springerlink.co