The magnetization reversal process is an intrinsic property of NdMn0.8Fe0.2O3 single crystal below TN = 59.5 K for magnetization field-cooled regime. The phenomenon is very anisotropic and a negative ...magnetization was observed below the compensation temperature TComp = 21.7(1) K; 25.9(1) K and 22.7(1) K for a-; b- and c-axis and field 0.01 T. Magnetocrystalline anisotropy results in different shape of hysteresis loop for any crystallographic orientation below TN. Ferromagnetic behavior, attributed to ordering of Nd sublattice, with coercive field of 1.32 T at temperature T = 2 K is typical for magnetic field applied along b-axis. Signature of ferromagnetic ordering exists even at 30 K. Very low hysteresis was observed in a–c plane and the a-axis magnetization loop has butterfly shape. A model of two Nd and Mn interpenetrating magnetic sublattices describes magnetization reversal better than a cluster model.
•Single crystal study.•Magnetization reversal process in NdMn0.8Fe0.2O3 originates from Nd and Mn interpenetrating magnetic sublattices.•Magentization reversal intirnsic only for FC magnetization.
Abstract
The heavy fermion paramagnet UTe
2
exhibits numerous characteristics of spin-triplet superconductivity. Efforts to understand the microscopic details of this exotic superconductivity have ...been impeded by uncertainty regarding the underlying electronic structure. Here we directly probe the Fermi surface of UTe
2
by measuring magnetic quantum oscillations in pristine quality crystals. We find an angular profile of quantum oscillatory frequency and amplitude that is characteristic of a quasi-2D Fermi surface, which we find is well described by two cylindrical Fermi sheets of electron- and hole-type respectively. Additionally, we find that both cylindrical Fermi sheets possess considerable undulation but negligible small-scale corrugation, which may allow for their near-nesting and therefore promote magnetic fluctuations that enhance the triplet pairing mechanism. Importantly, we find no evidence for the presence of any 3D Fermi surface sections. Our results place strong constraints on the possible symmetry of the superconducting order parameter in UTe
2
.
Despite belonging to a well-studied family of transition metal trihalides, VI3 has received significant attention only recently. As a hard ferromagnetic van der Waals compound with a large ...coercivity, it attracted much attention because of its potential use in atomically thin spintronic and optoelectronic devices. However, practical exploration of VI3 is challenging due to its instability under ambient conditions. Here, we present a comprehensive set of optical, x-ray diffraction, magnetization, and ellipsometric measurements of VI3 and demonstrate that, similarly to the related van der Waals ferromagnet CrI3, the degradation process is accelerated by the presence of moisture. The VI3 surface was covered by selected media commonly used in physical measurements to test its stability and lower the degradation rate three times or higher, providing practical information for experimentalists interested. The decomposition study at ambient conditions shows that the VI3 single crystal can be used for most of the bulk, magnetization, and optical measurements without any noticeable change of physical properties, as the significant degradation appears first after ∼2 h of exposition as illustrated, e.g., by the evolution of the ferromagnetic T1 and T2 transitions. The ellipsometric measurement demonstrates that even the surface remains optically stable for at least 5 min.
•The degradation of VI3 is accelerated by the presence of moisture, similarly to CrI3.•VI3 crystals are stable for most of the bulk experiments after a 2 h-exposition.•Ellipsometry shows that the surface remains optically stable for at least 5 min.
This paper is focused on the study of magneto crystalline anisotropy which we performed on oriented TbMn0.98Fe0.02O3 single crystal by magnetization and AC susceptibility measurements. Our ...measurements revealed huge magneto crystalline anisotropy with respect to main crystallographic axes. The paramagnetic Weiss temperature θp spans a broad range of values which can indicate the strong magnetocrystalline anisotropy in the system. Easy magnetization axis is c-axis and b-axis is hard magnetic axis. The magnetic phase transitions at TN, Tlock and T1 are connected with anomalies in magnetization and AC susceptibility measurements performed along b-axis. Field induced magnetic transitions were observed at 2 K in the case of a sinusoidally modulated collinear magnetic structure for magnetization measurements along a-axis and c-axis. Hysteresis loops measurements indicate suppression of Tb3+ ordering in high magnetic field which depends on crystal orientation. In respect to iron doping our results resemble and extend results obtained on powdered crystals. Iron doping shifts both TN and Tlock to lower temperatures, antiferromagnetic JAF interaction in ac-plane decreases leaving barely changed ferromagnetic interaction JF. The critical field of the field induced phase transition increases with iron doping.
•Our study confirmed huge magneto crystalline anisotropy of TbMn0.98Fe0.02O3.•Anomalies in M(T) and χ (T) at TN, Tlock and T1 are present only for b-axis.•Field induced magnetic transitions were observed at 2 K for a-axis and c-axis.•Suppression of Tb3+ ordering in high magnetic field depends on crystal orientation.•The critical field of the field induced phase transition increases with iron doping.
Abstract
The paper presents new knowledge on primary defect formation in tungsten (W) and iron (Fe) irradiated by fission and high-energy neutrons at near-room temperature. Using a well-established ...method of positron-annihilation lifetime-spectroscopy (PALS), it was found that irradiation of W in the fission reactor and by high-energy neutrons from the p(35 MeV)-Be generator leads to the formation of small radiation-induced vacancy clusters with comparable mean size. In the case of Fe, smaller mean size of primary radiation-induced vacancy clusters was measured after irradiation with fission neutrons compared to irradiation with high-energy neutrons from the p(35 MeV)-Be generator. It was found that one of the reasons of the formation of the larger size of the defects with lower density in Fe is lower flux in the case of irradiation with high-energy neutrons from the p(35 MeV)-Be source. The second reason is enhanced defect agglomeration and recombination within the energetic displacement cascade at high energy primary knock-on-atoms (PKAs). This is consistent with the concept of the athermal recombination corrected (arc-dpa) model, although the measured dpa cross-section of both fission neutrons and wide-spectrum high-energy neutrons in W is between the conventional Norgett–Robinson–Torrens (NRT-dpa) and arc-dpa predictions. This means that the physics of the primary radiation effects in materials is still not fully known and requires further study through a combination of modeling and experimental efforts. The present data serve as a basis for the development of an improved concept of the displacement process.
A new U-based compound of the U2Rh2Pb, a new compound of the U2T2X series (T – transition metal, X – Sn, In, Pb), was prepared in a single-crystal form. Its structure was determined as belonging to ...the tetragonal Mo2FeB2 structure type with the shortest U–U spacing along the c-axis. The crystals were subjected to study of magnetic, specific heat, and electrical resistivity in various magnetic fields. U2Rh2Pb undergoes an antiferromagnetic transition at a Néel temperature TN of 20 K and exhibits an enhanced Sommerfeld coefficient γ ≈ 150 mJ/molK2. In contrast to the two rhodium analogues U2Rh2In and U2Rh2Sn, the easy-magnetization direction is the c-axis with rather low value of the critical field Hc = 4.3 T of the metamagnetic transition of a spin-flip type. The observed dependences of TN and Hc on temperature and magnetic field have been used for constructing a magnetic phase diagram. The experimental observations are mostly supported by first-principles calculations.
We have prepared single crystals of a new compound U2Rh2Pb. Our research represents first single crystals study of lead compound in the U2T2X series. Figure shows the magnetic phase diagram of U2Rh2Pb. Antiferromagnet U2Rh2Pb is unique by unusual easy magnetization direction, the lowest value of the magnetic field inducing metamagnetic transition combined with very simple magnetic phase diagram. Display omitted
The article presents with the use of archive aerial photographs. The first task was to search and identify drainage detail from archive aerial photographs. The second task is to create procedures for ...processing aerial reconnaissance images (from WWII) to identify sites with potential pyrotechnic load. Both of these tasks are connecting by the effort to determine the internal orientation parameters of the cameras for using and easier calculation of exterior parameters by image correlation. Complete automation process searching of fiducial mark (FM) identification was implemented. The coordinates of all FM are calculated automatically from archive aerial photographs. In addition, the edges of the photographs are automatically found and a program was created to minimize of the cropping of the archive aerial photographs. The next part of the paper describes the procedures of averaging the values of the relative position of FM and transforming archive aerial photographs to a uniform dimension from a set of images taken with the same camera. The second part of the paper describes the process of creating a historical ortophoto with the standard calculation of bundle adjustment performed by an external process in the background of the OrthoEngine module using the Celery library installed as a python service. Finding of external image orientation parameters through bundle adjustment calculation are parameters, in the first, defined in the local system and then transformed into the national geodetic system of the Czech Republic. This entire section is available and free to use for on the internet. The third part of the article describes the practical procedure of the interpretation of archive and wartime photographs with aim of identification of the drainage detail and the procedures leading to the interpretation, identification, location and calculation of the position of unexploded air ammunition.
A comprehensive study of magnetocrystalline anisotropy of a layered van der Waals ferromagnet VI3 was performed. We measured angular dependences of the torque and magnetization with respect to the ...direction of the applied magnetic field within the basal ab plane and a general orthogonal plane to ab, respectively. A twofold butterflylike signal was detected by magnetization in the orthogonal plane. This signal symmetry remains conserved throughout all magnetic regimes as well as through the known structural transition down to the lowest temperatures. The maximum of the magnetization signal and the resulting magnetization easy axis is significantly tilted from the normal to the basal ab plane by ∼40°. The close relation of the magnetocrystalline anisotropy to the crystal structure was documented. In contrast, a two-fold-like angular signal was detected in the paramagnetic region within the ab plane in the monoclinic phase, which transforms into a six-fold-like signal below the Curie temperature TC. With further cooling, another six-fold-like signal with an angular shift of ∼30° grows approaching TFM. Below TFM, in the triclinic phase, the original six-fold-like signal vanishes, being replaced by a secondary six-fold-like signal with an angular shift of ∼30°.
The "Centre for Experimental Plant Biology", a joint project of the Institute of Experimental Botany of the Czech Academy of Sciences and CEITEC (represented by Mendel and Masaryk Universities), ...focused on elucidating the mechanisms of plant responses to abiotic and biotic stresses and their combinations at the cellular level, in intact plants during vegetative and reproductive stages, and fruit development. The consortium demonstrated the importance of shared research facilities, complementary approaches, and knowledge exchange, addressing demanding questions in plant biology. The consortium made breakthrough in plant-pathogen interactions, including identification of exocyst-syntaxin cooperation in non-host resistance. The results confirmed the fundamental role of phytohormones in stress responses, including negative correlation of leaf bioactive gibberellins with drought stress, and the role of cytokinins in ROS homeostasis, sulphur metabolism, and heat stress responses, including volatile emission. Molecular analyses revealed expansin-mediated cell wall remodelling, brassinosteroid-mediated regulation of root growth through PIN2, the role of ALBA and LARP6C proteins in pollen development under abiotic stress, and heat stress impact on fertilization rate, embryo and seed development. Gene Set Enrichment and RNA-Seq analyses allowed to identify crucial genes involved in the apple scab resistance network. The main results obtained during the five-year project are summarised here.
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