Giant Anomalous Hall Conductivity in the Itinerant Ferromagnet LaCrSb₃ and the Effect of f-Electrons

Itinerant ferromagnets constitute an important class of materials wherein spin polarization can affect the electric transport properties in nontrivial ways. One such phenomenon is anomalous Hall effect which depends on the details of the band structure such as the amount of band crossings in the valence band of the ferromagnet. Here, extraordinary anomalous Hall effect is found in an itinerant ferromagnetic metal LaCrSb3. The rather 2D nature of the magnetic subunit imparts large anisotropic anomalous Hall conductivity of 1250 Ω−1 cm−1 at 2 K. The investigations suggest that a strong Berry curvature by abundant momentum-space crossings and narrow energy-gap openings are the primary sources of the anomalous Hall conductivity. An important observation is the existence of quasi-dispersionless bands in LaCrSb3 which is now known to increase the anomalous Hall conductivity. After introducing f-electrons, anomalous Hall conductivity experiences more than twofold increase and reaches 2900 Ω−1 cm−1 in NdCrSb3. © 2021 The Authors. Advanced Quantum Technologies published by Wiley-VCH Gmb

Products of the reaction of chlorine atoms and ozone

Preliminary matrix-isolation infrared spectroscopic studies of the gas-phase reaction of chlorine atoms and ozone are reported. It was shown that the major product of the reaction is the symmetric OClO radical, while very little of the asymmetric ClOO radical is produced. It was also shown that the presence of O2 enhances the OClO production and the ClOO is the primary product in the reaction of Cl atoms and pure O2. The radical ClO was observed for the first time in a gas-phase reaction of Cl and O3. A mechanism for these observations is proposed

Reconceptualizing power and gendered subjectivities in domestic cooking spaces

Drawing on evidence from the Global North and South, this paper explores the power dynamics of domestic kitchens in different geographical contexts. Noting the gendered nature of domesticity, it contrasts those perspectives which regard women’s primary responsibility for foodwork as inherently oppressive, with others which see kitchens and associated domestic spaces as sites of potential empowerment for women. The paper explores the complex, spatially-distributed, character of power surrounding domestic foodwork, decentring Anglo-American understandings of the relationship between gender, power and domestic space by foregrounding the experiences of a range of women from across the globe. The paper also examines the increasing role of men in domestic settings, particularly in the Global North, assessing the extent to which their engagement in cooking and other domestic practices may be challenging conventional understandings of the relationship between gender, power and space. Focusing on the spatial dynamics of the domestic kitchen, this paper advances a more nuanced understanding of the co-constitutive nature of the relationship between gender and power, including the instabilities and slippages that occur in the performance of various domestic foodwork tasks. The paper advocates future research on the boundaries of home, work and leisure, focusing on their significance in the constitution and transformation of male and female subjectivities

BRILLOUIN SPECTRA IN AMORPHOUS SOLIDS

Author Institution: IBM Research Laboratory, San JosePolymeric solids are known to undergo a number of relaxational transitions. These transitions involve either changes in the skeletal and/or side group structure and their determination is strongly dependent on the frequency of the detection method and other extrinsic factors. This report deals with the detection of phase transitions in amorphous solids in the gigahertz range using acoustical phonons as a probe. The relationship of observed phonon velocities and scattering intensities to bulk properties is investigated and in certain cases it has also been possible to establish relaxation times associated with internal degrees of freedom in the sub-skeletal or side chain regions. Main consideration is given to developing a theory which accounts for changes observed in the Landau-Placzek ratio, absorption coefficients, and phonon velocities as temperature and phonon frequencies are varied. This is accomplished with the aid of an assumed distribution of relaxation times and frequency dependent elastic moduli

Anomalous Hall effect and the role of Berry curvature in Co₂TiSn Heusler films

Various Co-2-based Heusler compounds are predicted to be half-metallic ferromagnets with Weyl points. These systems with lack of time inversion symmetry possess a momentum space Berry curvature that can introduce exotic transport properties. The present study, on epitaxially grown Co2TiSn films, is an approach to understand and explore this possibility. The theoretical investigation shows that the Berry curvature is significant for the total anomalous Hall effect in experimentally grown Co2TiSn films. The deviation between the theory and experiment is due to the influence of side jump and skew scattering mechanisms. From a theoretical point of view, the intrinsic contribution to the anomalous Hall effect originates from partially gaped nodal lines due to the symmetry reduction induced by the lack of time reversal symmetry. Furthermore, from hard x-ray photoelectron spectroscopy measurements, we establish an electronic structure in the film that is comparable to the theoretical density of states calculations. These results provide intuitive insight into Heusler spintronics rooted in topological electronic structure

A molecular mechanics force field for conformational analysis of aliphatic acyclic amines

An improved molecular mechanics force field for conformational and vibrational studies of aliphatic acyclic amines is developed. The resulting force field reproduces molecular structures adequately and provides a good fit for energy differences between conformers and barriers to internal rotation for a large number of amines. In addition, vibrational frequencies are calculated in good agreement with available experimental data. When compared with existent force fields for amines, the present force field is considerably more simple and gives rise to calculated properties in closer agreement with experiment