Magnetic properties of antiferromagnetically coupled CoFeB/Ru/CoFeB

This work reports on the thermal stability of two amorphous CoFeB layers coupled antiferromagnetically via a thin Ru interlayer. The saturation field of the artificial ferrimagnet which is determined by the coupling, J, is almost independent on the annealing temperature up to more than 300 degree C. An annealing at more than 325 degree C significantly increases the coercivity, Hc, indicating the onset of crystallization.Comment: 4 pages, 3 figure

Antiferromagnetically coupled CoFeB/Ru/CoFeB trilayers

This work reports on the magnetic interlayer coupling between two amorphous CoFeB layers, separated by a thin Ru spacer. We observe an antiferromagnetic coupling which oscillates as a function of the Ru thickness x, with the second antiferromagnetic maximum found for x=1.0 to 1.1 nm. We have studied the switching of a CoFeB/Ru/CoFeB trilayer for a Ru thickness of 1.1 nm and found that the coercivity depends on the net magnetic moment, i.e. the thickness difference of the two CoFeB layers. The antiferromagnetic coupling is almost independent on the annealing temperatures up to 300 degree C while an annealing at 350 degree C reduces the coupling and increases the coercivity, indicating the onset of crystallization. Used as a soft electrode in a magnetic tunnel junction, a high tunneling magnetoresistance of about 50%, a well defined plateau and a rectangular switching behavior is achieved.Comment: 3 pages, 3 figure

Toward a script theory of guidance in computer-supported collaborative learning

This article presents an outline of a script theory of guidance for computer-supported collaborative learning (CSCL). With its four types of components of internal and external scripts (play, scene, role, and scriptlet) and seven principles, this theory addresses the question how CSCL practices are shaped by dynamically re-configured internal collaboration scripts of the participating learners. Furthermore, it explains how internal collaboration scripts develop through participation in CSCL practices. It emphasizes the importance of active application of subject matter knowledge in CSCL practices, and it prioritizes transactive over non-transactive forms of knowledge application in order to facilitate learning. Further, the theory explains how external collaboration scripts modify CSCL practices and how they influence the development of internal collaboration scripts. The principles specify an optimal scaffolding level for external collaboration scripts and allow for the formulation of hypotheses about the fading of external collaboration scripts. Finally, the article points towards conceptual challenges and future research questions

Learning to diagnose secondary school students' scientific reasoning skills in physics and biology: video-based simulations for pre-service teachers

Since the ability to teach and therefore also diagnose not only subject-specific but also cross-domain skills are an important part of every teacher’s day-to-day work, we developed simulations to quantify and furthermore support the competence to diagnose secondary school students’ scientific reasoning skills. For this purpose, the simulations also include the possibility to rehearse interdisciplinary collaborations between physics and biology pre-service teachers. The simulations are video-based, containing short, scripted videos showing two students working on different inquiry tasks, including a physics and a biology experiment. Participants have to observe the students and can individually decide which pre-formulated questions they want to ask the students before, during and after the experiments to gather relevant information. The corresponding simulated answers are subsequently presented via additional videos. The information gained during the simulations is supposed to be used to diagnose the students’ scientific reasoning skills later in the process

The diagnosis of scientific reasoning skills: how teachers' professional knowledge predicts their diagnostic accuracy

Diagnostic competences of teachers are an essential prerequisite for the individual support of students and, therefore, highly important. There is a substantial amount of research on teachers’ diagnostic competences, mostly operationalized as diagnostic accuracy, and on how diagnostic competences may be influenced by teachers’ professional knowledge base. While this line of research already includes studies on the influence of teachers’ content knowledge (CK), pedagogical content knowledge (PCK), and pedagogical-psychological knowledge (PK) on the diagnosis of subject-specific knowledge or skills, research on the diagnosis of cross-domain skills (i.e., skills relevant for more than one subject), such as scientific reasoning, is lacking although students’ scientific reasoning skills are regarded as important for multiple school subjects (e.g., biology or physics). This study investigates how the accuracy of pre-service teachers’ diagnosis of scientific reasoning is influenced by teachers’ own scientific reasoning skills (one kind of CK), their topic-specific knowledge (i.e., knowledge about a topic that constitutes the thematic background for teaching scientific reasoning; which is another kind of CK), and their knowledge about the diagnosis of scientific reasoning (one kind of PCK) and whether the relationships between professional knowledge and diagnostic accuracy are similar across subjects. The design of the study was correlational. The participants completed several tests for the kinds of professional knowledge mentioned and questionnaires for several control variables. To ensure sufficient variation in pre-service teachers’ PCK, half of the participants additionally read a text about the diagnosis of scientific reasoning. Afterwards, the participants completed one of two parallel video-based simulations (depicting a biology or physics lesson) measuring diagnostic accuracy. The pre-service teachers’ own scientific reasoning skills (CK) were a statistically significant predictor of diagnostic accuracy, whereas topic-specific knowledge (CK) or knowledge about the diagnosis of scientific reasoning (PCK), as manipulated by the text, were not. Additionally, no statistically significant interactions between subject (biology or physics) and the different kinds of professional knowledge were found. These findings emphasize that not all facets of professional knowledge seem to be equally important for the diagnosis of scientific reasoning skills, but more research is needed to clarify the generality of these findings