Reorientation phase transitions in thin magnetic films: a review of the classical vector spin model within the mean field approach

The ground state and the finite temperature phase diagrams with respect to magnetic configurations are studied systematically for thin magnetic films in terms of a classical Heisenberg model including magnetic dipole-dipole interaction and uniaxial anisotropy. Simple relations are derived for the occurrence of the various phase boundaries between the different regions of the magnetic orientations. In particular, the range of the first and second order reorientation phase transitions are determined for bi- and trilayers.Comment: 23 pages, LaTeX + 7 figures (Encapsulated PostScript), submitted to Philosophical Magazine B (Feb. 28, 2001

Is that an answer to the question? Analyzing the opening turns of physiotherapist-patient interactions

The dissertation is based on the linguistic-pragmatic analysis of 77 interactions between physiotherapists (PT) and patients during their first meeting. The research aims to explore 1) the characteristics of physiotherapists’ opening questions (OpQ), which initiate the problem presentation phase of the visit, 2) the patterns in patients’ answers (second turn – T2) to those questions, and 3) the relationship between the question-answer pairs. Convenience sampling resulted in the recruitment of 22 PTs (all female) and 77 patients (12 males and 65 females) from a single hospital in Budapest, Hungary. The first visits between the participants were audio recorded. Qualitative methods including the approaches of conversation analysis and linguistic pragmatics were applied to explore the characteristics of the OpQs, of the T2s, and the relationships between them. Additionally, statistical analysis of the OpQ-T2 relations was also conducted, using Pearson’s chi-square tests. The descriptive analysis identified four main categories of OpQs. Furthermore, 6 linguistic features were examined in each of the OpQs. Based on the information content of patients’ answers the inductive analysis resulted in the creation of 7 T2 categories. The results of the qualitative and quantitative analyses show that the examined linguistic features of the OpQs do not provide sufficient explanation for the observed variety in patients’ answers and their seemingly non-cooperative nature. The dissertation argues that the sociocognitive approach (SCA) provides an explanatory framework for the phenomena. The main point of this concept is that patients’ answers are influenced by the egocentric component of communication. In other words, patients’ prior experiences, and information that is important and salient for them all affect the content of their answers

Exchange Bias driven by Dzyaloshinskii-Moriya interactions

The exchange bias effect in compensated IrMn3/Co(111) system is studied using multiscale modeling from "ab initio" to atomistic calculations. We evaluate numerically the out-of-plane hysteresis loops of the bi-layer for different thickness of the ferromagnetic layer. The results show the existence of a perpendicular exchange bias field and an enhancement of the coercivity of the system. In order to elucidate the possible origin of the exchange bias, we analyze the hysteresis loops of a selected bi-layer by tuning the different contributions to the exchange interactions across the interface. Our results indicate that the exchange bias is primarily induced by the Dzyaloshinskii-Moriya interactions, while the coercivity is increased mainly due to a spin-flop mechanism