Influence of bi content on the temperature of the formation of the hard magnetic MnBi phase: simultaneous irreversible drop of resistance

Pulsed laser-deposited (PLD) MnBi films were fabricated by alternating deposition of Mn and Bi layers. In order to obtain the ferromagnetic MnBi phase, heat treatments were performed on the samples. Simultaneously, the resistance of the samples was monitored as a function of the temperature. Thus, on increasing the temperature, a steep decrease in the resistance of the films was observed, simultaneous to the onset of the formation of the MnBi phase. At room-temperature, these annealed samples showed a ferromagnetic behavior, as well as the presence of the characteristic LT-MnBi phase diffraction peaks in the X-ray diffraction patterns. The temperature of the generation of the MnBi phase depended on the relative concentration of Mn and Bi in the different samples: on increasing the Bi atomic concentration, the temperature of the generation of the MnBi phase decreased

Magnetic anisotropy in isotropic and nanopatterned strongly exchange-coupled nanolayers

UPNa. Departamento de Física. Laboratorio de MagnetismoIn this study, the fabrication of magnetic multilayers with a controlled value of the in-plane uniaxial magnetic anisotropy field in the range of 12 to 72 kA/m was achieved. This fabrication was accomplished by the deposition of bilayers consisting of an obliquely deposited (54A degrees) 8-nm-thick anisotropic Co layer and a second isotropic Co layer that was deposited at a normal incidence over the first layer. By changing the thickness value of this second Co layer (X) by modifying the deposition time, the value of the anisotropy field of the sample could be controlled. For each sample, the thickness of each bilayer did not exceed the value of the exchange correlation length calculated for these Co bilayers. To increase the volume of the magnetic films without further modification of their magnetic properties, a Ta spacer layer was deposited between successive Co bilayers at 54A degrees to prevent direct exchange coupling between consecutive Co bilayers. This step was accomplished through the deposition of multilayered films consisting of several (Co8 nm-54A degrees/Co (X nm-0A degrees)/Ta6 nm-54A degrees) trilayers.This work was partially supported by the Spanish government under project MAT2007-66252

Vanadium trapped by oblique nano-sheets to preserve the anisotropy in Co-V thin films at high temperature

In this study, oriented nano-sheets generated during the growth of cobalt-rich Co–V and Co–Zn thin films induced a large anisotropy in the magnetic and transport properties. The regular nano-sheets were tilted 52–54 deg. with respect to the substrate plane, ≈ 3.0–4.0 nm thick, ≈ 30–100 nm wide, and ≈ 200–300 nm long, with an inter-sheet distance of ≈ 0.9–1.2 nm. In spite of the different microstructures of the two kinds of samples where the Co–V films were amorphous, whereas the Co–Zn films showed a growth of Zn nanocrystals, the oblique nano-sheet morphology conferred noticeable shape anisotropy to both specimens. This anisotropy resulted in an in-plane uniaxial magnetic anisotropy. The changes in the nano-morphology caused by thermal treatments, and hence in their anisotropic properties, were studied. While the Co–V samples retained or increased their magnetic and transport anisotropies, this anisotropic behavior vanished for the annealed Co–Zn films. High resolution transmission electron microscopy, HRTEM, including chemical analysis at the nano-scale, and the dependence of the anisotropic resistance on temperature allowed to establish the nature and the activation energy spectra of the atomic relaxation processes during heating. These processes displayed a single peak at 1.63 eV for the Co–V and two peaks at 1.67 and 2.0 eV for the Co–Zn. These spectra and their singularities were associated to the changes induced in the nano-morphology of the films by thermal treatments. The Co–V films retained their nano-sheet morphology almost up to 500 ºC; the Co–Zn films lost their nano-sheets at 290 ºC. The thermal stability exhibited by the Co–V films makes them useful for applications in ultra high frequency, optical, magnetostrictive and magnetoelectric devices.C. F., J. V., and V. M. acknowledge the financial support of the Public University of Navarre. C.M. and M.R.I. acknowledge the financial support from the Spanish Ministerio de Economía y Competitividad in the project MAT2017–82970-C1 and C2-R and from the Aragón Regional project E26. Open access funding provided by Universidad Pública de Navarra

Aps Sustainable and Inclusive Social Volunteering: learning by doing a service stop the community (II)

El objetivo principal es consolidar el desarrollo de competencias genéricas y específicas que capacite a los y las participantes para transmitir la importancia de la Agenda 2030 en la universidad y la comunidad, desarrollando capacidades de reafirmación social para canalizar acciones encaminadas hacia los Objetivos de Desarrollo Sostenible (ODS). A través de la metodología del Aprendizaje-Servicio se busca promover un encuentro para el trabajo conjunto, mediante la conexión entre la individualidad de las personas, el trabajo grupal y comunitario. Los fundamentos del Trabajo Social nos permitirán trabajar un enfoque de derechos, valores y compromiso. Además, se promoverá el desarrollo de habilidades para la vida desde la educación popular, la educación eco-social, el diseño universal del aprendizaje, los entornos inclusivos, la lectura fácil y los huertos eco-didácticos. En el proyecto participará un grupo de veinte voluntarios/as (estudiantes de grado y máster de la Facultad de Trabajo Social y personas externas con diversidad intelectual), puntualmente estudiantes de Bellas Artes y Estudios Estadísticos. Como Aprendizaje, las actividades formativas programadas buscan formar al voluntariado tanto en los ODS como en las capacidades comentadas anteriormente. Para su desarrollo, se contará con recursos de las entidades colaboradoras, tanto propias de la UCM como externas. Como Servicio a la Comunidad, se propondrá al voluntariado el reto de ser embajadores/as de los ODS, compartiendo su mensaje en la universidad y comunidad, desde el conocimiento científico y el reconocimiento a los demás (cultura, saberes y procesos distintos a los nuestros). La gestión operativa se realizará a tres niveles: equipo técnico, para el seguimiento y evaluación del proyecto; equipo de acompañamiento, para coordinar actividades con el voluntariado y garantizar cohesión grupal; y equipo de relaciones institucionales, para coordinar con entidades colaboradoras los espacios y agenda para las actividades con el voluntariado.The main objective is to consolidate the development of generic and specific skills that train the participants to convey the importance of the 2030 Agenda in the university and the community, developing capacities for social reaffirmation to channel actions aimed at the Sustainable Development Goals ( ODS). Through the Service-Learning methodology, it seeks to promote a meeting for joint work, through the connection between the individuality of people, group and community work. The foundations of Social Work will allow us to work on a focus on rights, values ​​and commitment. In addition, the development of life skills will be promoted from popular education, eco-social education, universal learning design, inclusive environments, easy reading and eco-didactic gardens. A group of twenty volunteers will participate in the project (undergraduate and master's students from the Faculty of Social Work and external people with intellectual diversity), occasionally students of Fine Arts and Statistical Studies. As Learning, the programmed training activities seek to train volunteers both in the SDGs and in the capacities mentioned above. For its development, there will be resources from collaborating entities, both from the UCM and from outside. As Community Service, the challenge of being ambassadors of the SDGs will be proposed to volunteers, sharing their message in the university and community, based on scientific knowledge and recognition of others (culture, knowledge and processes different from ours). Operational management will be carried out at three levels: technical team, for the monitoring and evaluation of the project; support team, to coordinate activities with volunteers and guarantee group cohesion; and institutional relations team, to coordinate with collaborating entities the spaces and agenda for volunteer activities.Depto. de Trabajo Social y Servicios SocialesFac. de Trabajo SocialTRUEServicio ApS. Universidad Complutense de Madridunpu