Magnetic phase diagram of an Fe monolayer on W(110) and Ta(110) surfaces based on ab initio calculations

We present detailed investigations of the magnetic properties of an Fe monolayer on W and Ta (110) surfaces based on the ab initio screened Korringa-Kohn-Rostoker method. By calculating tensorial exchange coupling coefficients, the ground states of the systems are determined using atomistic spin dynamics simulations. Different types of ground states are found in the systems as a function of relaxation of the Fe layer. In case of W(110) substrate this is reflected in a reorientation of the easy axis from in-plane to out-of-plane. For Ta(110) a switching appears from the ferromagnetic state to a cycloidal spin spiral state, then to another spin spiral state with a larger wave vector and, for large relaxations, a rotation of the normal vector of the spin spiral is found. Classical Monte Carlo simulations indicate temperature-induced transitions between the different magnetic phases observed in the Fe/Ta(110) system. These phase transitions are analyzed both quantitatively and qualitatively by finite-temperature spin wave theory.Comment: 18 pages, 11 figure

Complex magnetic phase diagram and skyrmion lifetime in an ultrathin film from atomistic simulations

We determined the magnetic B-T phase diagram of PdFe bilayer on Ir(111) surface by performing Monte Carlo and spin dynamics simulations based on an effective classical spin model. The parameters of the spin model were determined by ab initio methods. At low temperatures we found three types of ordered phases, while at higher temperatures, below the completely disordered paramagnetic phase, a large region of the phase diagram is associated with a fluctuation-disordered phase. Within the applied model, this state is characterized by the presence of skyrmions with finite lifetime. According to the simulations, this lifetime follows the Arrhenius law as a function of temperature.Comment: 11 pages, 8 figure

A Török Köztársaság az átalakuló Közel-Keleten = The Republic of Turkey in the changing Middle East

A 2011–2012-ben zajlott, „arab tavasznak” nevezett események új korszak kezdetét jelezték a Közel-Keleten, mely a hidegháború vége óta, de különösen a 2003-as iraki háború következtében amúgy is mélyreható átalakulási folyamaton megy keresztül. Ennek során a térség három nem arab állama, Izrael, Irán és Törökország vált a régió hatalmi egyensúlyának meghatározó erőközpontjává, miközben az arab országok – amúgy sem homogén – csoportja a háttérbe szorult. A korábban mértékadó arab államok (Egyiptom, Irak, Szíria) különböző okok miatt elveszítették vonzerejüket a többiek számára, miközben Szaúd-Arábia sem vállalta a vezető szerepét. Az „arab tavasz” során egymástól egyre nyilvánvalóbban független nemzetállammá vált arab országok mind kevesebb kérdésben hajlandók közös álláspontot képviselni a nemzetközi fórumokon. Az átalakuló közel-keleti regionális rendben azonban az államok viszonylagos hatalmi egyensúlyában bekövetkezett változások miatt a térség helyzetét meghatározó szereplők száma megnövekedett, hiszen legalább Egyiptommal és Szaúd-Arábiával ismét mint politikai központtal kell számolni. A jelen tanulmány az e regionális rendben sokak szerint neooszmán hegemón törekvésekkel fellépő Törökország helyét és szerepét vizsgálja

Formation and stability of metastable skyrmionic spin structures with various topologies in an ultrathin film

We observe metastable localized spin configurations with topological charges ranging from $Q=-3$ to $Q=2$ in a (Pt$_{0.95}$Ir$_{0.05}$)/Fe bilayer on Pd$(111)$ surface by performing spin dynamics simulations, using a classical Hamiltonian parametrized by ab initio calculations. We demonstrate that the frustration of the isotropic exchange interactions is responsible for the creation of these various types of skyrmionic structures. The Dzyaloshinsky--Moriya interaction present due to the breaking of inversion symmetry at the surface energetically favors skyrmions with $Q=-1$, distorts the shape of the other objects, and defines a preferred orientation for them with respect to the underlying lattice.Comment: 9 pages manuscript, 3 figures, 4 table

Il Nuovo Proteo: Observations on behaviour, interaction, and performance in early modern Italian music

This dissertation aims to examine how the early modern discourse on behaviour and interaction emerging in Italian courtly circles influenced contemporary musical practice and debates thereof. The broader cultural context is drawn from courtesy books, written by authors arching from Baldassare Castiglione to Torquato Accetto, which not only reveal multi-layered moral concerns and complex systems of etiquettes, but also provide an intriguing ground for tracing significant ongoing aesthetic transformations during the era concerned. In Part One of the thesis I begin the discussion by setting out an overview of the culture of courtesy books; I reflect on issues relating to their production, their literary form and the epistemological connotations thereof, and in particular their readership. Subsequently, I provide a reading – latently governed from a musical perspective – of key volumes from the genre, in which I trace the core behavioural tropes of the courtier. I am particularly interested in how these tropes fare against the virtue ethical system of the time, and I argue for the growing importance of simulation and dissimulation within this dialogue. My examination culminates in the creation of a theoretical model I label as the continuous conversational performer – a metaphorical equivalent of the late sixteenth-century courtly participant, whose behavioural matrix is governed by a reinterpreted system of tropes and virtues. In Part Two I embark on my quest to seek connections between the behavioural patterns originally closely associated with the nobility and musical discourses of the time, including contributions by practising professional musicians. I project the gained knowledge from Part One onto various musical theoretical and aesthetic exchanges (including the Galilei-Zarlino debate), and I argue that the skills and values of the continuous conversational performer manifest themselves in methods of delivery within musical performance. At the heart of this section is the inner perspective of the musical performer, where I introduce the notion of performative mindsets – a theoretical framework that reflects on multiple strands of communicative strategies emerging from the different approaches to the potential role of the musical performer in the era concerned. Part Three is dedicated more directly to musical practice, and I explore how the behavioural matrix of the continuous conversational performer may have played out in various practical scenarios and musical environments. The protagonists of this section are primarily associated with the courts of Ferrara, Florence, Mantua, and Rome, and with the so-called ‘new music’ of the late sixteenth and early seventeenth centuries. My central focus here is on examining texts written by professional musicians that explicitly deal with a broad range of matters relating to performance. I offer novel insights into Giulio Caccini’s musical interpretation of the Castiglionian notion of sprezzatura; I examine the toolbox of expressive singing through the lens of courtly behavioural ideals; and, finally, I argue that ultimately the tropes and virtues of the continuous conversational performer come to full fruition in the newly emerging genre of court opera