TY - JOUR AU - Itatani, Masaki AU - Onishi, Yuhei AU - Suematsu, Nobuhiko J. AU - Lagzi, István László TI - Periodic Precipitation in a Confined Liquid Layer JF - JOURNAL OF PHYSICAL CHEMISTRY LETTERS J2 - J PHYS CHEM LETT VL - 15 PY - 2024 SP - 4948 EP - 4957 PG - 10 SN - 1948-7185 DO - 10.1021/acs.jpclett.4c00832 UR - https://m2.mtmt.hu/api/publication/34830134 ID - 34830134 LA - English DB - MTMT ER - TY - JOUR AU - Tóth, Boglárka AU - Farkas, Dániel Gergely AU - Amelin, K. AU - Rõõm, T. AU - Nagel, U. AU - Udvardi, László AU - Szunyogh, László AU - Rózsa, Levente AU - Ito, T. AU - Bordács, Sándor TI - Terahertz spin-wave excitations in the transverse conical phase of BiFeO3 JF - PHYSICAL REVIEW B J2 - PHYS REV B VL - 109 PY - 2024 IS - 14 PG - 10 SN - 2469-9950 DO - 10.1103/PhysRevB.109.144424 UR - https://m2.mtmt.hu/api/publication/34823661 ID - 34823661 LA - English DB - MTMT ER - TY - JOUR AU - Vajtai, Lili AU - Nemes, Norbert Marcel AU - Morales, Maria del Puerto AU - Molnár, Kolos AU - Pinke, Balazs Gabor AU - Simon, Ferenc TI - Incidence of the Brownian Relaxation Process on the Magnetic Properties of Ferrofluids JF - NANOMATERIALS J2 - NANOMATERIALS-BASEL VL - 14 PY - 2024 IS - 7 PG - 15 SN - 2079-4991 DO - 10.3390/nano14070634 UR - https://m2.mtmt.hu/api/publication/34801218 ID - 34801218 N1 - Department of Physics, Institute of Physics, HUN-REN-BME Condensed Matter Research Group, Budapest University of Technology and Economics, Műegyetem rkp. 3., Budapest, H-1111, Hungary Departamento de Física de Materiales, Universidad Complutense de Madrid, Madrid, 28040, Spain Department of Nanoscience and Nanotechnology, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Madrid, 28049, Spain Department of Polymer Engineering, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Műegyetem rkp. 3., Budapest, H-1111, Hungary HUN–REN–BME Research Group for Composite Science and Technology, Műegyetem rkp. 3., Budapest, H-1111, Hungary MTA-BME Lendület Sustainable Polymers Research Group, Műegyetem rkp. 3., Budapest, H-1111, Hungary Institute for Solid State Physics and Optics, HUN-REN Wigner Research Centre for Physics, P.O. Box 49, Budapest, H-1525, Hungary Export Date: 22 April 2024 Correspondence Address: Nemes, N.M.; Departamento de Física de Materiales, Spain; email: nmnemes@ucm.es AB - Ferrofluids containing magnetic nanoparticles represent a special class of magnetic materials due to the added freedom of particle tumbling in the fluids. We studied this process, known as Brownian relaxation, and its effect on the magnetic properties of ferrofluids with controlled magnetite nanoparticle sizes. For small nanoparticles (below 10 nm diameter), the Neel process is expected to dominate the magnetic response, whereas for larger particles, Brownian relaxation becomes important. Temperature- and magnetic-field-dependent magnetization studies, differential scanning calorimetry, and AC susceptibility measurements were carried out for 6 and 13.5 nm diameter magnetite nanoparticles suspended in water. We identify clear fingerprints of Brownian relaxation for the sample of large-diameter nanoparticles as both magnetic and thermal hysteresis develop at the water freezing temperature, whereas the samples of small-diameter nanoparticles remain hysteresis-free down to the magnetic blocking temperature. This is supported by the temperature-dependent AC susceptibility measurements: above 273 K, the data show a low-frequency Debye peak, which is characteristic of Brownian relaxation. This peak vanishes below 273 K. LA - English DB - MTMT ER - TY - JOUR AU - Nagyfalusi, Balázs AU - Szunyogh, László AU - Palotás, Krisztián TI - Real-space nonlocal Gilbert damping from exchange torque correlation applied to bulk ferromagnets and their surfaces JF - PHYSICAL REVIEW B J2 - PHYS REV B VL - 109 PY - 2024 IS - 9 PG - 8 SN - 2469-9950 DO - 10.1103/PhysRevB.109.094417 UR - https://m2.mtmt.hu/api/publication/34749016 ID - 34749016 LA - English DB - MTMT ER - TY - JOUR AU - Nagyfalusi, Balázs AU - Udvardi, László AU - Szunyogh, László AU - Rózsa, Levente TI - Chemical potential of magnetic skyrmion quasiparticles in heavy-metal/iron bilayers JF - PHYSICAL REVIEW B J2 - PHYS REV B VL - 109 PY - 2024 IS - 9 PG - 9 SN - 2469-9950 DO - 10.1103/PhysRevB.109.094418 UR - https://m2.mtmt.hu/api/publication/34749006 ID - 34749006 LA - English DB - MTMT ER - TY - JOUR AU - Sükösd, Csaba AU - Bokor, Nándor TI - Relativisztikusan mozgó állóhullám JF - FIZIKAI SZEMLE J2 - FIZIKAI SZEMLE VL - 74 PY - 2024 IS - 2 SP - 66 EP - 70 PG - 5 SN - 0015-3257 UR - https://m2.mtmt.hu/api/publication/34738091 ID - 34738091 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Márkus, Ferenc AU - Gambár, Katalin TI - Quantized Approach to Damped Transversal Mechanical Waves JF - QUANTUM REPORTS J2 - QUANTUM REPORTS VL - 6 PY - 2024 IS - 1 SP - 120 EP - 133 PG - 14 SN - 2624-960X DO - 10.3390/quantum6010009 UR - https://m2.mtmt.hu/api/publication/34719922 ID - 34719922 N1 - Department of Physics, Budapest University of Technology and Economics, Műegyetem rkp. 3, Budapest, H-1111, Hungary Department of Natural Sciences, Institute of Electrophysics, Kálmán Kandó Faculty of Electrical Engineering, Óbuda University, Tavaszmező u. 17, Budapest, H-1084, Hungary Department of Natural Sciences, National University of Public Service, Ludovika tér 2, Budapest, H-1083, Hungary Export Date: 5 April 2024 Correspondence Address: Márkus, F.; Department of Physics, Műegyetem rkp. 3, Hungary; email: markus.ferenc@ttk.bme.hu AB - In information transfer, the dissipation of a signal is of crucial importance. The feasibility of reconstructing the distorted signal depends on the related permanent loss. Therefore, understanding the quantized dissipative transversal mechanical waves might result in deep insights. In particular, it may be valid on the nanoscale in the case of signal distortion, loss, or even restoration. Based on the description of the damped quantum oscillator, we generalize the canonical quantization procedure for the case of the transversal waves. Then, we deduce the related damped wave equation and the state function. We point out the two possible solutions of the propagating-damping wave equation. One involves the well-known Gaussian spreading solution superposed with the damping oscillation, in which the loss of information is complete. The other is the Airy function solution, which is non-spreading–propagating, so the information loss is only due to oscillation damping. However, the structure of the wave shape remains unchanged for the latter. Consequently, this fact may allow signal reconstruction, resulting in the capability of restoring the lost information. LA - English DB - MTMT ER - TY - JOUR AU - Tanaka, Hayato AU - Lagzi, István László AU - Nakanishi, Hideyuki TI - In Situ Observation of Perovskite Quantum Dots Driven by Photopolymerization Controlled Using a Digital Micromirror Device (Advanced Optical Materials 5/2024) JF - ADVANCED OPTICAL MATERIALS J2 - ADV OPT MATER VL - 12 PY - 2024 IS - 5 SP - 202470012 SN - 2195-1071 DO - 10.1002/adom.202470012 UR - https://m2.mtmt.hu/api/publication/34657449 ID - 34657449 LA - English DB - MTMT ER - TY - JOUR AU - Nyáry, Anna AU - Balogh, Zoltán AU - Vigh, Máté AU - Sánta, Botond AU - Pósa, László AU - Halbritter, András Ernő TI - Voltage-time dilemma and stochastic threshold-voltage variation in pure-silver atomic switches JF - PHYSICAL REVIEW APPLIED J2 - PHYS REV APPL VL - 21 PY - 2024 IS - 1 SN - 2331-7019 DO - 10.1103/PhysRevApplied.21.014027 UR - https://m2.mtmt.hu/api/publication/34554374 ID - 34554374 AB - The formation and dissolution of silver nanowires plays a fundamental role in a broad range of resistive-switching devices, which fundamentally rely on the electrochemical-metallization phenomenon. It has been shown that resistive switching may also appear in pure metallic nanowires lacking any silver-ion-hosting embedding environment but this pure atomic switching mechanism differs fundamentally from the conventional electrochemical-metallization-based resistive switching. To facilitate the quantitative description of the former phenomenon, we investigate a broad range of Ag atomic junctions, with a special focus on the frequency dependence and the fundamentally stochastic cycle-to-cycle variation of the switching-threshold voltage. These devices are established in an ultrahigh-purity environment in which electrochemical metallization can be excluded. The measured characteristics are successfully described by a vibrational-pumping model, yielding consistent predictions for the weak frequency dependence and the large variance of the switching-threshold voltage. We also demonstrate that electrochemical-metallization-based resistive switching and pure atomic switching may appear in the same device structure and therefore the proper understanding of the pure atomic switching mechanism has a very relevant importance in silver-based electrochemical-metallization cells. © 2024 American Physical Society. LA - English DB - MTMT ER - TY - JOUR AU - Fehérvári, János Gergő AU - Balogh, Zoltán AU - Török, Tímea Nóra AU - Halbritter, András Ernő TI - Noise tailoring, noise annealing, and external perturbation injection strategies in memristive Hopfield neural networks JF - APL machine learning. J2 - APL mach. learn. VL - 2 PY - 2024 IS - 1 PG - 15 SN - 2770-9019 DO - 10.1063/5.0173662 UR - https://m2.mtmt.hu/api/publication/34536907 ID - 34536907 AB - The commercial introduction of a novel electronic device is often preceded by a lengthy material optimization phase devoted to the suppression of device noise as much as possible. The emergence of novel computing architectures, however, triggers a paradigm shift in noise engineering, demonstrating that non-suppressed but properly tailored noise can be harvested as a computational resource in probabilistic computing schemes. Such a strategy was recently realized on the hardware level in memristive Hopfield neural networks, delivering fast and highly energy efficient optimization performance. Inspired by these achievements, we perform a thorough analysis of simulated memristive Hopfield neural networks relying on realistic noise characteristics acquired on various memristive devices. These characteristics highlight the possibility of orders of magnitude variations in the noise level depending on the material choice as well as on the resistance state (and the corresponding active region volume) of the devices. Our simulations separate the effects of various device non-idealities on the operation of the Hopfield neural network by investigating the role of the programming accuracy as well as the noise-type and noise amplitude of the ON and OFF states. Relying on these results, we propose optimized noise tailoring and noise annealing strategies, comparing the impact of internal noise to the effect of external perturbation injection schemes. LA - English DB - MTMT ER -