About

Abdon Sepulveda is an Associate Adjunct Professor in the Department of Mechanical and Aerospace Engineering at UCLA Samueli School of Engineering. His research interests encompass multidisciplinary structural and system optimization, finite element analysis, reliability, alternative analysis, and control systems. Additionally, he works on nanoscale multiferroic materials, piezoelectric materials, energy harvesting, and energy storage. His work focuses on advancing understanding and development in these areas, contributing to the fields of engineering and materials science.

Research topics

• Materials science
• Physics
• Condensed matter physics
• Quantum mechanics
• Chemistry
• Nuclear magnetic resonance
• Waste management
• Thermodynamics
• Environmental science
• Composite material
• Optoelectronics
• Electrical engineering
• Engineering
• Process engineering
• Nuclear engineering
• Optics

Selected publications

• Arrayed single-cell capture and release using localized oersted fields

  Journal of materials research/Pratt's guide to venture capital sources · 2025-11-28

  articleSenior author
  PublisherDOI

• Imaging of voltage-controlled switching of magnetization in highly magnetostrictive epitaxial Fe–Ga microstructures

  Nanoscale · 2024-01-01 · 4 citations

  articleOpen access

  The magnetoelectric behavior of epitaxial Fe-Ga microstructures on top of a (001)-oriented PMN-PT piezoelectric substrate is imaged with magnetic X-ray microscopy. Additionally, the micron-scale strain distribution in PMN-PT is characterized by X-ray microdiffraction and examined with respect to the results of the Fe-Ga magnetoelectric switching. The magnetic reorientation of Fe-Ga is found to be strongly correlated with size, shape, and crystallographic orientation of the microstructures. In the case of square-shaped structures, size dictates the influence of the strain distribution on both the initialization of the ground state and on the magnetic reorientation during application of voltage. On the other hand, elliptical microstructures demonstrate completely different magnetic responses depending on the relative orientation of their long axis with respect to the crystallographic directions of the PMN-PT. This study demonstrates that engineering the behavior of highly magnetostrictive epitaxial microdevices is possible. It further elucidates that voltage-induced actuation can be largely tuned to achieve the desired type of magnetic switching ranging from vortex circulation reversal, domain wall motion, to a large rotation of magnetization. Because of the outstanding properties of the investigated material system, the reported findings are expected to be of great interest for the realization of next-generation energy-efficient magnetic memory and logic devices.

  PublisherOA PDFDOI

• Arrayed Single-Cell Capture and Release Using Localized Oersted Fields

  SSRN Electronic Journal · 2023-01-01

  preprintOpen accessSenior author
  PublisherDOI

• A Lamb wave magnetoelectric antenna design for implantable devices

  Applied Physics Letters · 2023-05-15 · 14 citations

  articleSenior author

  A 400 MHz magnetoelectric (ME) Lamb wave antenna design to function in the medical implant communication service band is proposed. The antenna employs a heterostructure of piezoelectric and magnetostrictive membranes to acoustically excite standing shear bulk wave and radiate as a magnetic dipole. Multiphysics finite element analysis simulations are performed for transmission and reception modes. In these simulations, three aspects are investigated: piezoelectricity, micromagnetic precession, and magnetic dipole radiation. An experimental demonstration of the antenna is also conducted and shows mechanical resonance with a Q-factor of 500 and ME coupling. These results indicate that the design can be operated in zero-order antisymmetric (A0) mode as a tunable oscillator or sensor. This ME approach provides a solution to the miniaturization problem of traditional current-based implantable antennas.

  PublisherDOI

• Stress-induced Néel vector reorientation in <b> <i>γ</i> </b>-FeMn antiferromagnetic thin films

  Applied Physics Letters · 2022 · 6 citations

  • Materials science
  • Condensed matter physics
  • Composite material

  The relationship between stresses and the orientation of the Néel vector were studied by varying the residual stresses in magnetron sputtered FeMn thin films by adjusting Argon working pressures. Quasistatic magnetization and AC susceptibility measurements reveal that the FeMn film with compressive stress (−27 MPa/−0.015% strain) possesses an out-of-plane Néel vector orientation with a 44 kOe spin-flop field, as contrasted to the FeMn film with tensile stress (25 MPa/0.014% strain) showing an in-plane orientation with a 34 kOe spin-flop field. An energy formulation for the films estimates a magnetostriction value of 109 ppm following an effective anisotropy of −8 kJ/m3. The film with the larger residual stress (77 MPa/0.043% strain) displayed a strain-induced phase transition from γ-FeMn to α-FeMn. These results show the dependency of the Néel vector on the stress state indicative of relatively large magnetostriction.

  PublisherDOI

• Modeling Incoherent Strain Mediated Multiferroic Bennett Clocking

  arXiv (Cornell University) · 2020-01-06 · 1 citations

  preprintOpen accessSenior author

  Strain mediated Bennett clocking has only recently been experimentally demonstrated and suffered from high error rates. Most models used to explain this behavior are macrospin models. Predictions of these models do not match experimental designs since they consider all spins rotating coherently and no magnetoelastic strain feedback. In this paper a fully coupled nonlinear model (LLG plus elastodynamics) was used to simulate voltage induced Bennett clocking. This modelling captures the full spin dynamics as well as shape anisotropy. Two materials were studied (Ni and Terfenol-D) which have very different exchange lengths. The simulation results show that incoherent rotation may occur due to the uniaxial nature of the magnetoelastic coupling.

  PublisherOA PDFDOI

• Energy storage efficiency optimization of methane reforming with CO2 reactors for solar thermochemical energy storage☆

  Applied Energy · 2020 · 30 citations

  • Process engineering
  • Nuclear engineering
  • Environmental science
  PublisherDOI

• Voltage manipulation of magnetic particles using multiferroics

  Journal of Physics D Applied Physics · 2020 · 10 citations

  Senior authorCorresponding
  • Condensed matter physics
  • Materials science
  • Physics

  Abstract Precise control and manipulation of nano-beads have various applications, e.g. cell sorter, 3D printing and nano-motors. In this paper we present an approach in which we use voltage on a piezolecetric substrate in order to reorient the magnetization of a nano-disk. In turn this magnetization drives the dynamic of the nano-beads. This is an energy efficient method to control the nano-beads motion since only voltage is applied to the substrate. The mechanism consists of a Ni disk and three pairs of surface electrodes placed on a PZT substrate. By controlling the voltage applied on the different pairs of electrodes, the magnetization of the Ni disk will rotate with constant angular velocity. The rotating magnetization will then generate magnetic force on the soft-magnetic nano-beads driving the motion. For the beads, full 3D dynamics consider both translation and rotation and the forces considered are magnetic, drag, friction and adhesion. With this model we are able to have a realistic description for the particle behavior.

  PublisherDOI

• Strain-mediated Symmetry Breaking Switch with Perpendicular Magnetic Anisotropy

  arXiv (Cornell University) · 2020-01-04

  preprintOpen accessSenior author

  Magnetic switch with perpendicular magnetic anisotropy (PMA) is a promising method for controlling magnetization in several applications like magnetic tunnel junction and magnetic memory. However, incoherence happens during the switch process and lower the switch frequency of the magnetic bits. Symmetry broking can help solve this problem. Here, we present a field-free method for the symmetry broking and then increase the switch speed of the magnetization. A strain-mediated method with geometric asymmetry is presented here. In this work, we build a finite element model that consists a 50 nanometer diameter nanodisk with a varied thickness on the top of a 50 nanometer thick PZT (Pby[ZrxTi1-x]O3) thin film. The results show a 66% faster switch than symmetry PMA switching (0.85 nanosecond to 0.29 nanosecond) under same energy consumption. Finally, we explore the mechanism of the symmetry broking of varying thickness nanodot with calculating the energy profile.

  PublisherOA PDFDOI

• Capturing magnetic bead-based arrays using perpendicular magnetic anisotropy

  Applied Physics Letters · 2019-08-19 · 13 citations

  articleOpen access

  Designing and implementing means of locally trapping magnetic beads and understanding the factors underlying the bead capture force are important steps toward advancing the capture-release process of magnetic particles for biological applications. In particular, capturing magnetically labeled cells using magnetic microstructures with perpendicular magnetic anisotropy (PMA) will enable an approach to cell manipulation for emerging lab-on-a-chip devices. Here, a Co (0.2 nm)/Ni (0.4 nm) multilayered structure was designed to exhibit strong PMA and large saturation magnetization (Ms). Finite element simulations were performed to assess the dependence of the capture force on the value of Ms. The simulated force profile indicated the largest force at the perimeter of the disks. Arrays of Co/Ni disk structures of (4–7) μm diameter were fabricated and tested in a microchannel with suspended fluorescent magnetic beads. The magnetic beads were captured and localized to the edge of the disks as predicted by the simulations. This approach has been demonstrated to enable uniform assembly of magnetic beads without external fields and may provide a pathway toward precise cell manipulation methods.

  PublisherOA PDFDOI

Frequent coauthors

• Gregory P. Carman

  University of California System

  20 shared

• Greg P. Carman

  15 shared

• L. A. Schmit

  University of California, Los Angeles

  12 shared

• Cheng-Yen Liang

  12 shared

• Scott Keller

  University of California, Riverside

  12 shared

• H.A. Jensen

  12 shared

• J. W. Hu

  9 shared

• Cai Chen

  8 shared