218 research outputs found
The Demonic and the Seductive in Religious Nationalism : Vinayak Damodar Savarkar and the Rites of Exorcism in Secularizing South Asia
The relationship between religion and nationalism is explored in this paper which takes Vinayak Damodar Savarkar as its core focus of analysis. Given the incomplete process of nation-building in the case of India and the intrinsic challenge of how to cultivate a nationalism when the sense of a nation and nationality is lacking, Nandy discusses Savarkar’s idea of Hindutva and the use of religion as a vehicle of nation-building. This, despite Savarkar’s being a non-believer. Nandy explores parallels with Muhammad Ali Jinnah, whose project of nation and state-building is also seen in terms of political categories that were drawn from the Western experience and ideal of the Westphalian state. Exploring the love-hate relationship with Savarkar that is prevalent in contemporary India, Nandy probes the concerted attempt to demonise Savarkar and asks whether this is yet another means by which a young nation seeks to exorcise its past
Motoren bag indisk nationalisme
Ashis Nandy om indisk nationalisme. 
Generation of single skyrmions by picosecond magnetic field pulses
We numerically demonstrate an ultrafast method to create
skyrmions in a ferromagnetic sample by applying a
picosecond (effective) magnetic field pulse in the presence of
Dzyaloshinskii-Moriya interaction. For small samples the applied magnetic field
pulse could be either spatially uniform or nonuniform while for large samples a
nonuniform and localized field is more effective. We examine the phase diagram
of pulse width and amplitude for the nucleation. Our finding could ultimately
be used to design future skyrmion-based devices.Comment: 4.5 pages+Supplemental Materia
Switching of chiral magnetic skyrmions by picosecond magnetic field pulses via transient topological states
Magnetic chiral skyrmions are vortex like spin structures that appear as
stable or meta-stable states in magnetic materials due to the interplay between
the symmetric and antisymmetric exchange interactions, applied magnetic field
and/or uniaxial anisotropy. Their small size and internal stability make them
prospective objects for data storage but for this, the controlled switching
between skyrmion states of opposite polarity and topological charge is
essential. Here we present a study of magnetic skyrmion switching by an applied
magnetic field pulse based on a discrete model of classical spins and atomistic
spin dynamics. We found a finite range of coupling parameters corresponding to
the coexistence of two degenerate isolated skyrmions characterized by mutually
inverted spin structures with opposite polarity and topological charge. We
demonstrate how for a wide range of material parameters a short inclined
magnetic field pulse can initiate the reliable switching between these states
at GHz rates. Detailed analysis of the switching mechanism revealed the complex
path of the system accompanied with the excitation of a chiral-achiral meron
pair and the formation of an achiral skyrmion
Second-order topological superconductor via noncollinear magnetic texture
We put forth a theoretical framework for engineering a two-dimensional (2D)
second-order topological superconductor (SOTSC) by utilizing a heterostructure:
incorporating noncollinear magnetic textures between an s-wave superconductor
and a 2D quantum spin Hall insulator. It stabilizes the higher order
topological superconducting phase, resulting in Majorana corner modes (MCMs) at
four corners of a 2D domain. The calculated non-zero quadrupole moment
characterizes the bulk topology. Subsequently, through a unitary
transformation, an effective low-energy Hamiltonian reveals the effects of
magnetic textures, resulting in an effective in-plane Zeeman field and
spin-orbit coupling. This approach provides a qualitative depiction of the
topological phase, substantiated by numerical validation within exact
real-space model. Analytically calculated effective pairings in the bulk
illuminate the microscopic behavior of the SOTSC. The comprehension of MCM
emergence is aided by a low-energy edge theory, which is attributed to the
interplay between effective pairings of (px + py )-type and (px + ipy )-type.
Our extensive study paves the way for practically attaining the SOTSC phase by
integrating noncollinear magnetic textures
Role of Berry phase theory for describing orbital magnetism: From magnetic heterostructures to topological orbital ferromagnets
We address the importance of the modern theory of orbital magnetization for
spintronics. Based on an all-electron first-principles approach, we demonstrate
that the predictive power of the routinely employed "atom-centered"
approximation is limited to materials like elemental bulk ferromagnets, while
the application of the modern theory of orbital magnetization is crucial in
chemically or structurally inhomogeneous systems such as magnetic thin films,
and materials exhibiting non-trivial topology in reciprocal and real
space,~e.g.,~Chern insulators or non-collinear systems. We find that the modern
theory is particularly crucial for describing magnetism in a class of materials
that we suggest here topological orbital ferromagnets.Comment: 5 pages, 4 figure
Pressure controlled trimerization for switching of anomalous Hall effect in triangular antiferromagnet MnSn
Here, we present a detailed theoretical and experimental study on the
pressure induced switching of anomalous Hall effect (AHE) in the triangular
antiferromagnetic (AFM) compound MnSn. Our theoretical model suggests
pressure driven significant splitting of the in-plane Mn bond lengths an
effective trimerization, which in turn stabilizes a helical AFM ground state by
modifying the inter-plane exchange parameters in the system. We experimentally
demonstrate that the AHE in MnSn reduces from 5 cm at ambient
pressure to zero at an applied pressure of about 1.5 GPa. Furthermore, our
pressure dependent magnetization study reveals that the conventional triangular
AFM ground state of MnSn systematically transforms into the helical AFM
phase where the symmetry does not support a non-vanishing Berry curvature
required for the realization of a finite AHE. The pressure dependent x-ray
diffraction (XRD) study rules out any role of structural phase transition in
the observed phenomenon. In addition, the temperature dependent in-plane
lattice parameter at ambient pressure is found to deviate from the monotonic
behavior when the system enters into the helical AFM phase, thereby, supporting
the proposed impact of trimerization in controlling the AHE. We believe that
the present study makes an important contribution towards understanding the
stabilization mechanism of different magnetic ground states in MnSn and
related materials for their potential applications pertaining to AHE switching
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