arXiv subjects

José Araújo

Publications and source records attributed to José Araújo.

6 recordsLinked to original sources

arXiv2026

Unifying Magnetic, Electrical, and Thermoelectric Responses in a Non-Collinear Antiferromagnet

Non-collinear antiferromagnets offer unconventional routes for controlling magnetic, electrical, and thermoelectric responses through their complex spin configurations and interfacial symmetry. Here, we detect exceptional interfacial properties arising from a non-collinear antiferromagnet by demonstrating a robust and quantitatively consistent exchange-bias response in an IrMn$_3$/Py heterostructure. The system consists of a 10 nm IrMn$_3$ layer coupled to a 5 nm permalloy (Py) film. Longitudinal magneto-optical Kerr effect (MOKE), anisotropic magnetoresistance (AMR), and anomalous Nernst effect (ANE) measurements independently reveal the same unidirectional field shift of approximately 50 Oe, together with a consistent cosine angular dependence. The simultaneous observation of these signatures establishes a direct correspondence between the interfacial magnetic symmetry imposed by the non-collinear antiferromagnet and the responses of the adjacent ferromagnet. This symmetry is manifested consistently in magnetization reversal, charge transport, and thermally driven voltage generation, demonstrating that the exchange-bias imprint is not restricted to a single experimental observable. Our results reveal a coherent multifunctional response of IrMn$_3$/Py and extend the conventional understanding of exchange bias beyond collinear antiferromagnetic systems. More broadly, they demonstrate the potential of non-collinear antiferromagnets as platforms for coupling magnetic, electrical, and thermoelectric functionalities in spintronic and spin-caloritronic devices.

cond-mat.mtrl-sci↗

arXiv2026

Resonantly Enhanced Phonon Transport by Magnon Pumping in a Ferromagnetic/Piezoelectric Bilayer

We report the first experimental observation of resonantly enhanced propagating phonon transport induced by magnon pumping in a ferromagnetic/piezoelectric bilayer. Surface acoustic waves (SAWs) generated in a 128$^{\circ}$ Y-cut LiNbO$_3$ delay-line device resonantly excite magnetization dynamics in an adjacent Co film through magnetoelastic coupling. The enhancement of the transmitted acoustic signal occurs exclusively when the SAW frequency satisfies the ferromagnetic resonance condition predicted by the Kittel dispersion, providing a direct experimental fingerprint of resonant magnon-phonon coupling. A systematic comparison between the Co/LiNbO$_3$ bilayer and the bare LiNbO$_3$ substrate demonstrates that the observed transmission enhancement originates solely from the dynamic interaction between propagating phonons and coherent magnetization precession. Furthermore, measurements performed at different SAW harmonics reveal that only the harmonic satisfying the FMR condition produces a measurable enhancement, confirming the frequency-selective nature of the phenomenon. These findings establish an efficient mechanism for transferring energy from magnons to propagating phonons and provide a new strategy for actively controlling coherent acoustic transport in hybrid spintronic, straintronic, and quantum phononic platforms.

cond-mat.mes-hall↗

arXiv2025

MatChA: Cross-Algorithm Matching with Feature Augmentation

State-of-the-art methods fail to solve visual localization in scenarios where different devices use different sparse feature extraction algorithms to obtain keypoints and their corresponding descriptors. Translating feature descriptors is enough to enable matching. However, performance is drastically reduced in cross-feature detector cases, because current solutions assume common keypoints. This means that the same detector has to be used, which is rarely the case in practice when different descriptors are used. The low repeatability of keypoints, in addition to non-discriminatory and non-distinctive descriptors, make the identification of true correspondences extremely challenging. We present the first method tackling this problem, which performs feature descriptor augmentation targeting cross-detector feature matching, and then feature translation to a latent space. We show that our method significantly improves image matching and visual localization in the cross-feature scenario and evaluate the proposed method on several benchmarks.

cs.CV↗

arXiv2025

Controlling magnetic damping with spintronic thermal effects in Py/Fe3O4-PANI bilayers

We report experiments that control magnetic damping in Py/Fe3O4-PANI via two spintronic thermal effects: spin Seebeck and anomalous Nernst. Magnetic damping is measured using ferromagnetic resonance (FMR) techniques, where the sample is excited by microwave radiation and the resulting DC voltage is detected in the Fe3O4-PANI film. When a temperature gradient is applied in the longitudinal configuration, the DC voltage linewidth increases or decreases depending on the direction of the thermal gradient. This finding demonstrates that magnetic damping in Py/Fe3O4-PANI can be controlled by currents induced by thermal effects. Remarkably, the absolute linewidth changes observed in Py/Fe3O4-PANI exceed those seen in bilayers of ferrimagnetic insulator yttrium iron garnet and heavy metal by more than an order of magnitude. We interpret the significant change in magnetic damping as a result of intrinsic phenomena occurring in bilayers.

cond-mat.mtrl-sci↗

arXiv2024

New method of image processing via statistical analysis for application in intelligent systems

Image processing has always been a topic of significant importance to society. Recently, this field has gained considerable prominence due to the development of intelligent systems. In this work, we present a new method of image processing that utilizes statistical analysis, specifically designed for applications in intelligent systems. We tested our method on a large collection of images to assess its effectiveness.

physics.data-an↗

arXiv2024

Observing a quantum magnetic effect in CaYAl3O7-X particles (X=Ni, Fe, Co)

Yttrium calcium aluminate, with the formula CaYAl3O7, has been extensively researched due to its remarkable luminescent properties when doped or co-doped. Additionally, it exhibits exceptional piezoelectric properties at high temperatures. However, the potential magnetic properties this material can acquire through doping or co-doping have largely gone unexplored until now. In this innovative study, we investigate the quantum magnetic characteristics of yttrium calcium aluminate particles doped with transition metals such as cobalt, iron, and nickel. Our magnetic measurements of hysteresis curves in the macroscopic regime reveal intriguing magnetic characteristics that have not been documented in the literature. Given the high applicability of this material in biological microelectromechanical systems, we conducted a detailed study to demonstrate these findings.

cond-mat.mtrl-sci↗