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230 results on '"Franco, Victorino"'

1. Barocaloric effect of elastomers and plastic crystals: an outlook

Author

Andrade, Vivian, Paixão, Lucas S., Carvalho, Alexandre M. G., Franco, Victorino, and Reis, Mario S.

Subjects
Condensed Matter - Materials Science
Abstract

The urge for efficient and environmentally friendly alternatives for the current gas-based refrigeration is becoming more critical due to global warming and overpopulation. Among the main candidates, solid-state-based cooling technology is appealing to substitute the conventional systems. Recently, attention has been turned to the barocaloric effect in advanced materials, namely, plastic crystals and elastomers, with reports revealing great caloric responses around room temperature for a series of materials. In this sense, this review has the goal of collecting, organizing and comparing the results from the literature to provide an outlook on the subject.

Published
2022

16. Perspectives and Energy Applications of Magnetocaloric, Pyromagnetic, Electrocaloric, and Pyroelectric Materials.

Author

Klinar, Katja, Law, Jia Yan, Franco, Victorino, Moya, Xavier, and Kitanovski, Andrej

Subjects
CARBON dioxide mitigation, ENERGY harvesting, MAGNETICS, MAGNETIC fields, ELECTRIC fields
Abstract

This perspective provides an overview of the state of research and innovation in the areas of magnetocaloric and pyromagnetic materials, and electrocaloric and pyroelectric materials, including the overlapping sub‐areas of multicaloric and multipyro materials that can operate simultaneously under the application of magnetic and electric fields. These materials are critically examined for their potential to revolutionize cooling, heating, and energy‐harvesting applications. This perspective first summarizes the state‐of‐the‐art advancements and highlights recent significant developments. Then, it is identified and discussed that the prevailing challenges hindering the widespread adoption of technologies based on these materials. In this context, after consulting with members of the caloric and pyro communities, a technology roadmap is outlined to guide research efforts in overcoming current barriers to applications, with the goal of achieving impactful results by 2040. This roadmap emphasizes the importance of focusing on under‐researched materials, novel devices, and application spaces, paving the way for interdisciplinary efforts that can lead to significant reductions in carbon dioxide emissions. [ABSTRACT FROM AUTHOR]

Published
2024
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19. Applicability of scaling behavior and power laws in the analysis of the magnetocaloric effect in second-order phase transition materials

Author

Romero-Muñiz, Carlos, Tamura, Ryo, Tanaka, Shu, and Franco, Victorino

Subjects
Condensed Matter - Materials Science, Condensed Matter - Statistical Mechanics
Abstract

In recent years, universal scaling has gained renewed attention in the study of magnetocaloric materials. It has been applied to a wide variety of pure elements and compounds, ranging from rare earth-based materials to transition metal alloys, from bulk crystalline samples to nanoparticles. It is therefore necessary to quantify the limits within which the scaling laws would remain applicable for magnetocaloric research. For this purpose, a threefold approach has been followed: a) the magnetocaloric responses of a set of materials with Curie temperatures ranging from 46 to 336 K have been modeled with a mean-field Brillouin model, b) experimental data for Gd has been analyzed, and c) a 3D-Ising model ---which is beyond the mean-field approximation--- has been studied. In this way we can demonstrate that the conclusions extracted in this work are model-independent. It is found that universal scaling remains applicable up to applied fields which provide a magnetic energy to the system up to 8\% of the thermal energy at the Curie temperature. In this range, the predicted deviations from scaling laws remain below the experimental error margin of carefully performed experiments. Therefore, for materials whose Curie temperature is close to room temperature, scaling laws at the Curie temperature would be applicable for the magnetic field range available at conventional magnetism laboratories ($\sim 10$ T), well above the fields which are usually available for magnetocaloric devices., Comment: 14 pages, 11 figures

Published
2016
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24. Relative Cooling Power and Temperature Averaged Entropy Change in La₁.₃₄Sr₁.₆₆Mn₂O₇: Magnetocaloric Effects

Author

Saw, Ajay Kumar, Nunez, J. Peter J., Hadimani, Ravi L., Gupta, Shalabh, Franco, Victorino, and Dayal, Vijaylakshmi

Abstract

In this digest, we explore the structural, magnetic, and magnetocaloric characteristics of the Ruddlesden–Popper (RP) manganite La1.34Sr1.66Mn2O7 synthesized via the solid-state reaction method. The X-ray diffraction analysis reveals a tetragonal crystal structure with space group I4/mmm. The sample exhibits a metal-to-insulator transition at $T_{\mathrm {MI}} = 128.47$ K at 0 T and 183.07 K at 8 T. Magnetization measurements reveal a paramagnetic (PM)-to-ferromagnetic (FM) transition at $T_{C}$ , which is 113 K at 0.01 T and shifts to 164 K at 7 T. The magnetocaloric performances are assessed by calculating the maximum magnetic entropy change ( $\Delta S_{m}$ ), relative cooling power (RCP), and temperature-averaged entropy change (TEC) with a 5 K increment. $\Delta S_{m}$ is 0.6, 3.0, and 3.7 J/kgK under a magnetic field of 0.5, 4, and 7 T, respectively, attributed to the establishment of long-range FM ordering with increasing magnetic field. Proper FM ordering results in the broadening of the ( ${\delta T}_{\mathrm {FWHM}}$ ), enhancing the RCP from 12.12 to 201.45 J/kg with a field change from 0.5 to 7 T. The TEC value is maximum at lower $\Delta T_{H-C}$ values, 4.12 (3.00) J/kg $\cdot $ K for 7(4) T.

Published
2024
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30. Competitive driving effect on calorics by dual-fields in ferroic materials with strong magnetostructural coupling

Author

Hao, Jia-Zheng, primary, Wang, Bing-jie, additional, Hu, Feng-Xia, additional, Wang, Jing, additional, Wang, Jian-Tao, additional, Zhou, Hou-Bo, additional, Shen, Fei-Ran, additional, Liang, Fei-Xiang, additional, Yu, Zi-Bing, additional, Gao, Yi-Hong, additional, Law, Jia-Yan, additional, Franco, Victorino, additional, He, Lun-Hua, additional, He, Jun, additional, Liu, Dan, additional, Sun, Ji-Rong, additional, and Shen, Bao-Gen, additional

Published
2023
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31. Current perspective in magnetocaloric materials research.

Author

Law, Jia Yan, Moreno-Ramírez, Luis M., Díaz-García, Álvaro, and Franco, Victorino

Subjects
ALLOYS, REFRIGERATION & refrigerating machinery
Abstract

Magnetocaloric refrigeration has remained a promising alternative to conventional refrigeration for the last few decades. The delay in reaching the market is significantly based on materials' related issues, such as hysteresis/reversibility, mechanical stability, or formability. This perspective paper shows the current trends in magnetocaloric materials research, highlighting the families of alloys and compounds that are gaining attention in the recent years. It also includes an overview of novel approaches that can be used to analyze these properties that could improve the applicability of magnetocaloric materials. [ABSTRACT FROM AUTHOR]

Published
2023
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37. Magneto-caloric effect in the pseudo-binary intermetallic YPrFe17 compound

Author

Álvarez, Pablo, Gorria, Pedro, Llamazares, José L. Sánchez, Pérez, María J., Franco, Victorino, Reiffers, Marian, Kovác, Jozef, Puente-Orench, Inés, and Blanco, Jesús A.

Subjects
Condensed Matter - Materials Science
Abstract

We have synthesized the intermetallic YPrFe17 compound by arc-melting. X-ray and neutron powder diffraction show that the crystal structure is rhombohedral with View the MathML source space group (Th2Zn17-type). The investigated compound exhibits a broad isothermal magnetic entropy change {\Delta}SM(T) associated with the ferro-to-paramagnetic phase transition (TC \approx 290 K). The |{\Delta}SM| (\approx 2.3 J kg-1 K-1) and the relative cooling power (\approx 100 J kg-1) have been calculated for applied magnetic field changes up to 1.5 T. A single master curve for {\Delta}SM under different values of the magnetic field change can be obtained by a rescaling of the temperature axis. The results are compared and discussed in terms of the magneto-caloric effect in the isostructural R2Fe17 (R = Y, Pr and Nd) binary intermetallic alloys., Comment: Preprint, 5 pages (postprint), 4 figures, regular paper

Published
2012
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43. Review on magnetocaloric high-entropy alloys: Design and analysis methods

Author

Junta de Andalucía, Universidad de Sevilla, Air Force Office of Scientific Research (US), Law, Jia Yan, Franco, Victorino, Junta de Andalucía, Universidad de Sevilla, Air Force Office of Scientific Research (US), Law, Jia Yan, and Franco, Victorino

Abstract

The search for high-performance functional alloys with improved service life and reliability entails the optimization of their mechanical properties. Recently, the high-entropy alloy (HEA) design concept has found new alloys with excellent mechanical properties. It utilizes multiprincipal elements to yield high configurational entropy of mixing, entailing a large compositional freedom with wide window of opportunities for property exploration. Their functional properties are usually modest when compared to conventional materials. The discovery of HEAs with optimal combination of mechanical and functional properties would be a leap forward in the reliability of functional devices. This review article focuses on magnetocaloric HEAs, the design approaches, and the appropriate analysis methods for their performance. We will highlight the efficient strategic search within the vast HEA space, which has been instrumental for significantly enhancing MCE performance, closing the pre-existing gap between magnetocaloric HEAs and high-performance conventional magnetocaloric materials. Outlook for future directions will also be included. Graphical abstract: [Figure not available: see fulltext.]

Published
2023

48. Temperature-FORC analysis of a magnetocaloric Heusler alloy using a unified driving force approach (T*FORC).

Author

Franco, Victorino

Subjects
*HEUSLER alloys, *TRANSITION temperature, *PHASE transitions
Abstract

Temperature-first order reversal curve (FORC) distributions of thermomagnetic phase transitions are a fingerprinting tool to identify features of the phase transformations of the material. However, they have two major limitations: qualitative character, due to the shift of the loops with increasing driving forces, and long experimental time. The use of an effective temperature that takes into account the different driving forces affecting the transformation allows for a more quantitative comparison of the features of the FORC distributions, as it eliminates the need for an ad hoc selection of the origin of the distribution axes. At the same time, experimental measurements as a function of this effective temperature are significantly faster than purely temperature loops, hinting at a future possibility of time and cost efficient FORC characterization of temperature dependent transitions. [ABSTRACT FROM AUTHOR]

Published
2020
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