Tuning magnetocrystalline anisotropy of Fe3_{3}Sn by alloying

The electronic structure, magnetic properties and phase formation of hexagonal ferromagnetic Fe$_{3}$Sn-based alloys have been studied from first principles and by experiment. The pristine Fe$_{3}$Sn compound is known to fulfill all the requirements for a good permanent magnet, except for the magnetocrystalline anisotropy energy (MAE). The latter is large, but planar, i.e. the easy magnetization axis is not along the hexagonal c direction, whereas a good permanent magnet requires the MAE to be uniaxial. Here we consider Fe$_{3}$Sn$_{0.75}$M$_{0.25}$, where M= Si, P, Ga, Ge, As, Se, In, Sb, Te and Bi, and show how different dopants on the Sn sublattice affect the MAE and can alter it from planar to uniaxial. The stability of the doped Fe$_{3}$Sn phases is elucidated theoretically via the calculations of their formation enthalpies. A micromagnetic model is developed in order to estimate the energy density product (BH)max and coercive field $\mu_{0}$H$_{c}$ of a potential magnet made of Fe$_{3}$Sn$_{0.75}$Sb$_{0.25}$, the most promising candidate from theoretical studies. The phase stability and magnetic properties of the Fe$_{3}$Sn compound doped with Sb and Mn has been checked experimentally on the samples synthesised using the reactive crucible melting technique as well as by solid state reaction. The Fe$_{3}$Sn-Sb compound is found to be stable when alloyed with Mn. It is shown that even small structural changes, such as a change of the c/a ratio or volume, that can be induced by, e.g., alloying with Mn, can influence anisotropy and reverse it from planar to uniaxial and back

Size-induced superantiferromagnetism with reentrant spin-glass behavior in metallic nanoparticles of TbCu2

An unusual 4f -superantiferromagnetic state characterized by simultaneous antiferromagnetic and spin-glass behaviors induced by particle-size reduction is revealed in metallic nanoparticles (≈ 9 nm) of TbCu 2 . The Néel temperature is 46 K and the glassy freezing is below ≈ 9 K and governed by a critical slowing down process. Neutron diffraction at 1.8 K establishes the superantiferromagnetism. The latter is settled by the nanoparticle moments and the freezing mechanism is provided by the surface spins

Database of novel magnetic materials for high-performance permanent magnet development

This paper describes the open Novamag database that has been developed for the design of novel Rare-Earth free/lean permanent magnets. Its main features as software technologies, friendly graphical user interface, advanced search mode, plotting tool and available data are explained in detail. Following the philosophy and standards of Materials Genome Initiative, it contains significant results of novel magnetic phases with high magnetocrystalline anisotropy obtained by three computational high-throughput screening approaches based on a crystal structure prediction method using an Adaptive Genetic Algorithm, tetragonally distortion of cubic phases and tuning known phases by doping. Additionally, it also includes theoretical and experimental data about fundamental magnetic material properties such as magnetic moments, magnetocrystalline anisotropy energy, exchange parameters, Curie temperature, domain wall width, exchange stiffness, coercivity and maximum energy product, that can be used in the study and design of new promising high-performance Rare-Earth free/lean permanent magnets. The results therein contained might provide some insights into the ongoing debate about the theoretical performance limits beyond Rare-Earth based magnets. Finally, some general strategies are discussed to design possible experimental routes for exploring most promising theoretical novel materials found in the database.European Horizon 2020 Framework Programme for Research and Innovation (2014-2020) under Grant Agreement No. 686056, NOVAMAG. European Regional Development Fund in the IT4Innovations national supercomputing center – path to exascale project, project number CZ 02.1.01/0.0/0.0/16–013/0001791 within the Operational Programme Research, Development and Educatio

Melanoma Models for the Next Generation of Therapies

There is a lack of appropriate melanoma models that can be used to evaluate the efficacy of novel therapeutic modalities. Here, we discuss the current state of the art of melanoma models including genetically engineered mouse, patient-derived xenograft, zebrafish, and ex vivo and in vitro models. We also identify five major challenges that can be addressed using such models, including metastasis and tumor dormancy, drug resistance, the melanoma immune response, and the impact of aging and environmental exposures on melanoma progression and drug resistance. Additionally, we discuss the opportunity for building models for rare subtypes of melanomas, which represent an unmet critical need. Finally, we identify key recommendations for melanoma models that may improve accuracy of preclinical testing and predict efficacy in clinical trials, to help usher in the next generation of melanoma therapies

Gamificación en tiempos de pandemia: rediseño de una experiencia en educación superior

Durante las cuarentenas sufridas en la mayoría de los países durante los primeros meses de la pandemia, uno de los problemas específicos de los docentes fue mantener el interés de su alumnado en unas condiciones desfavorables. En este contexto, la gamificación es una metodología que, en el ámbito docente, favorece la implicación del estudiantado en su aprendizaje gracias a componentes lúdicos que mantienen motivados a los participantes. En este trabajo analizamos una experiencia de gamificación para estudiantes de diversas ingenierías diseñada para una docencia presencial y su adaptación al entorno en línea. Los principales resultados observados fueron la existencia de una correlación entre la participación activa del estudiante en el programa y presentarse al examen, así como una mejoría en el aprendizaje de los conceptos y métodos de resolución de problemas de la asignatura, lo cual redundó en un incremento en el porcentaje de aprobados con respecto al total de alumnos presentados al compararlos con los grupos de control. La percepción del alumnado sobre la experiencia apunta a que se sienten más comprometidos con la asignatura y consideran que les ha servido para mejorar su aprendizaje. Palabras clave: Enseñanza politécnica; Aprendizaje en grupo; Motivación; Gamificación. Gamifying in times of pandemic: redesign of a higher education experience Abstract: During the quarantines suffered in most countries during the first months of the pandemic, one of the specific problems of lecturers was to maintain the interest of their students in unfavorable conditions. In this context, gamification is a methodology that, in the teaching field, favors the involvement of students in their learning thanks to playful components that keep the participants motivated. In this work we analyze a comprehensive gamification experience for students of various engineering degrees designed for face-to-face teaching and its adaptation to the online environment. The main results observed were the existence of a correlation between the active participation of the student in the program and taking the exam, as well as an improvement in the learning of the concepts and methods of solving problems of the subject, which resulted in an increase in the percentage of students who passed the subject with respect to the total number of students who took the exam when comparing them with the control groups. The students' perception of the experience indicates that they feel more committed to the subject and consider that it has served to improve their learning. Keywords: Polytechnic education; Group learning; Motivation; Gamification.Durante las cuarentenas sufridas en la mayoría de los países durante los primeros meses de la pandemia, uno de los problemas específicos de los docentes fue mantener el interés de su alumnado en unas condiciones desfavorables. En este contexto, la gamificación es una metodología que, en el ámbito docente, favorece la implicación del estudiantado en su aprendizaje gracias a componentes lúdicos que mantienen motivados a los participantes. En este trabajo analizamos una experiencia de gamificación para estudiantes de diversas ingenierías diseñada para una docencia presencial y su adaptación al entorno en línea. Los principales resultados observados fueron la existencia de una correlación entre la participación activa del estudiante en el programa y presentarse al examen, así como una mejoría en el aprendizaje de los conceptos y métodos de resolución de problemas de la asignatura, lo cual redundó en un incremento en el porcentaje de aprobados con respecto al total de alumnos presentados al compararlos con los grupos de control. La percepción del alumnado sobre la experiencia apunta a que se sienten más comprometidos con la asignatura y consideran que les ha servido para mejorar su aprendizaje. Palabras clave: Enseñanza politécnica; Aprendizaje en grupo; Motivación; Gamificación. Gamifying in times of pandemic: redesign of a higher education experience Abstract: During the quarantines suffered in most countries during the first months of the pandemic, one of the specific problems of lecturers was to maintain the interest of their students in unfavorable conditions. In this context, gamification is a methodology that, in the teaching field, favors the involvement of students in their learning thanks to playful components that keep the participants motivated. In this work we analyze a comprehensive gamification experience for students of various engineering degrees designed for face-to-face teaching and its adaptation to the online environment. The main results observed were the existence of a correlation between the active participation of the student in the program and taking the exam, as well as an improvement in the learning of the concepts and methods of solving problems of the subject, which resulted in an increase in the percentage of students who passed the subject with respect to the total number of students who took the exam when comparing them with the control groups. The students' perception of the experience indicates that they feel more committed to the subject and consider that it has served to improve their learning. Keywords: Polytechnic education; Group learning; Motivation; Gamification

Muntadas : Hibridos

Bonet traces Muntadas's work thematically from 1963 to 1987 while Mercader, in a reprinted text from 1967, employs the hybrid as a metaphor for multi-media and multi-disciplinary productions. Biographical notes. 67 bibl. ref

On the polemic with L. N. Tolstoy: the axiology of F. M. Dostoevsky in the «A Writer's Diary»

В статье описаны ценности и идеи Ф. М. Достоевского, которые писатель передает в споре с Л. Н. Толстым в «Дневнике писателя» за июль–август 1877 г. Достоевский анализирует значение России для стран Европы, миссию русской литературы и особый характер русского народа. Все эти аспекты для писателя связаны с духовно-нравственной сферой, которая позволит России объединить славянские страны и дать Европе ключ к решению многих вопросов.The article is devoted to the values and ideas of F. M. Dostoevsky, which the writer conveys in a dispute with L. N. Tolstoy in the «A Writer's Diary» for July–August 1877. Dostoevsky analyzes the significance of Russia for the countries of Europe, the mission of Russian literature and the special character of the Russian people. All these aspects for the writer are connected with the spiritual and moral sphere, which will allow Russia to unite the Slavic countries and give Europe the key to solving many issues

Half-Heusler Phase Formation and Ni Atom Distribution in M-Ni-Sn (M = Hf, Ti, Zr) systems

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