La Roca, Paulo Matías
Loading...
Email Address
person.page.identifierURI
Birth Date
Job Title
Last Name
La Roca
First Name
Paulo Matías
person.page.departamento
Ciencias
person.page.instituteName
InaMat2. Instituto de Investigación en Materiales Avanzados y Matemáticas
ORCID
person.page.observainves
person.page.upna
Name
- Publications
- item.page.relationships.isAdvisorOfPublication
- item.page.relationships.isAdvisorTFEOfPublication
- item.page.relationships.isAuthorMDOfPublication
2 results
Search Results
Now showing 1 - 2 of 2
Publication Open Access Room temperature huge magnetocaloric properties in low hysteresis ordered Cu-doped Ni-Mn-In-Co alloys(Elsevier, 2022) La Roca, Paulo Matías; López García, Javier; Sánchez-Alarcos Gómez, Vicente; Recarte Callado, Vicente; Rodríguez Velamazán, José Alberto; Pérez de Landazábal Berganzo, José Ignacio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Gobierno de Navarra / Nafarroako Gobernua, PC017–018 AMELECThe reduction of the thermal hysteresis in first order magnetostructural transition is a determining factor to decrease energy losses and to improve the efficiency of magnetocaloric cooling based systems. In this work, a Cu doped NiMnInCo metamagnetic shape memory alloy (MMSMA) exhibiting a narrow thermal hysteresis (around 5 K) at room temperature has been designed. In this alloy, the induced L21 ordering process affects the phase stability in an unusual way compared to that observed in NiMnInCo and other NiMn based alloys. This ordering produces an increase in the Curie temperature of the austenite but hardly affects the mar tensitic transformation temperatures. As a consequence, the ordering increases the magnetization of the austenite without changing the transformation temperatures, doubles the sensitivity of the transformation to magnetic fields (the Claussius-Clapeyron slope goes from 2.1 to 3.9 K/T), improves the magnetocaloric effect, the reversibility and finally, enhances the refrigeration capacity. In addition, the magnetic hysteresis losses are among the lowest reported in the literature and the effective cooling capacity coefficient RCeff reaches 86 J/Kg for 2 T (15 % higher than those found in Ni-Mn based alloys) and 314 J/Kg for 6 T fields. Therefore, the ordered alloy possesses an excellent combination of low thermal hysteresis and high RCeff, not achieved previously in metamagnetic shape memory alloys near room temperature.Publication Open Access A short review on the effect of Cr on the fcc-hcp phase transition in Fe-Mn-based alloys(Springer, 2020) Guerrero, L.M.; La Roca, Paulo Matías; Malamud, M.F.; Baruj, A.; Sade, M.; Ciencias; ZientziakThe effect of Cr on the fcc–hcp martensitic transformation in the Fe–Mn–Cr system has been discussed considering different aspects: (a) the relative phase stabilities, (b) the magnetic order of the fcc phase, (c) the structural parameters and volume change between fcc and hcp, (d) the driving force of the martensitic transformation and relevant thermodynamics quantities, (e) the thermal cycling behavior, and (f) the pseudoelastic effect. Particularly, in this work it has been found that when Cr content increases, the effect of cycling on the energy barrier decreases. This may be explained by a small volume change, which could lead to a slighter introduction of plastic deformation during thermal cycling through the martensitic transition.