arXiv subjects

Erick Burgos-Parra

Publications and source records attributed to Erick Burgos-Parra.

4 recordsLinked to original sources

arXiv2026

Experimental verification of the conservation of the magnetic moment and the longitudinal invariant

Adiabatic invariants are fundamental to plasma physics but are often treated as purely theoretical concepts in undergraduate courses due to the difficulty of experimentally demonstrating them. This paper presents a pedagogical experiment to visualize and quantitatively verify the conservation of the magnetic moment ($μ$) and the longitudinal invariant ($J$) using a standard educational electron charge-to-mass ratio apparatus configured as a magnetic bottle. By analyzing long-exposure photographs of the electron beam trajectory, we reconstructed the helical motion and calculated the invariants under different magnetic field configurations. Our results verify the conservation of the longitudinal invariant ($J$) with a ratio of 0.98 between configurations. The magnetic moment ($μ$) exhibited a coefficient of variation of approximately 7\%, a deviation consistent with the presence of collisional effects in the tube. These findings demonstrate that complex plasma dynamics can be effectively studied using accessible laboratory equipment, providing a valuable bridge between theory and experiment for physics students.

physics.ed-ph↗

arXiv2026

Influence of Local Icosahedral Short-Range Order on the Magnetization Dynamics of Amorphous Cobalt-Iron Nanodisks

The microscopic origin of soft magnetic properties in amorphous alloys is fundamentally linked to the interplay between local topological disorder and magnetic exchange interactions. In this work, we employ a multiscale Spin-Lattice Dynamics (SLD) approach to investigate the magnetostructural correlations in amorphous Co$_{x}$Fe$_{1-x}$ nanodisks ($x=35, 50, 65$). By integrating classical molecular dynamics with a generalized magnetic Hamiltonian, we capture the dynamic feedback loop between lattice vibrations and spin precession. Topological analysis via Voronoi tessellation reveals a persistent species-dependent structural heterogeneity: Cobalt atoms preferentially adopt "solid-like" icosahedral packing, forming a rigid structural backbone, whereas Iron atoms exhibit a higher propensity for "liquid-like" disordered environments. We demonstrate that this topological disparity dictates the macroscopic magnetic response. The Cobalt-driven structural stiffness preserves a robust exchange network that maximizes saturation magnetization, while the local disorder inherent to Iron-rich regions introduces exchange fluctuations that act as an intrinsic damping mechanism, delaying magnetic relaxation. These findings provide an atomistic explanation for the stability of ferromagnetic order in Co-Fe metallic glasses and offer a pathway for tuning damping parameters in amorphous spintronic devices through stoichiometric control.

cond-mat.mtrl-sci↗

arXiv2021

Chiral spin spiral in synthetic antiferromagnets probed by circular dichroism in x-ray resonant magnetic scattering

Noncollinear chiral spin textures in ferromagnetic multilayers are at the forefront of recent research in nano-magnetism with the promise for fast and energy-efficient devices. The recently demonstrated possibilities to stabilize such chiral structures in synthetic antiferromagnets (SAF) has raised interests as they are immune to dipolar field, hence favoring the stabilization of ultra small textures, improve mobility and avoid the transverse deflections of moving skyrmions limiting the efficiency in some foreseen applications. However, such systems with zero net magnetization are hence difficult to characterize by most of the standard techniques. Here, we report that the relevant parameters of a magnetic SAF texture, those being its period, its type (Néel or Bloch) and its chirality (clockwise or counterclockwise), can be directly determined using the circular dichroism in x-ray resonant scattering (CD-XRMS) at half integer multilayer Bragg peaks in reciprocal space. The analysis of the dependence in temperature down to 40K allows us moreover to address the question of the temperature stability of a spin spiral in a SAF sample and of the temperature scaling of the symmetric and antisymmetric exchange interactions.

cond-mat.mtrl-sci↗

arXiv2021

Ultrafast time-evolution of chiral Néel magnetic domain walls probed by circular dichroism in x-ray resonant magnetic scattering

Non-collinear spin textures in ferromagnetic ultrathin films are attracting a renewed interest fueled by possible fine engineering of several magnetic interactions, notably the interfacial Dzyaloshinskii-Moriya interaction. This allows the stabilization of complex chiral spin textures such as chiral magnetic domain walls (DWs), spin spirals, and magnetic skyrmions. We report here on the ultrafast behavior of chiral DWs after optical pumping in perpendicularly magnetized asymmetric multilayers, probed using time-resolved circular dichroism in x-ray resonant magnetic scattering (CD-XRMS). We observe a picosecond transient reduction of the CD-XRMS, which is attributed to the spin current-induced coherent and incoherent torques within the continuously dependent spin texture of the DWs. We argue that a specific demagnetization of the inner structure of the DW induces a flow of hot spins from the interior of the neighboring magnetic domains. We identify this time-varying change of the DW textures shortly after the laser pulse as a distortion of the homochiral N'eel shape toward a transient mixed Bloch-Néel-Bloch textures along a direction transverse to the DW. Our study highlights how time-resolved CD-XRMS can be a unique tool for studying the time evolution in other systems showing a non-collinear electric/magnetic ordering such as skyrmion lattices, conical/helical phases, as well as the recently observed antiskyrmion lattices, in metallic or insulating materials.

cond-mat.mtrl-sci↗