21 research outputs found
Tourism 4.0: Challenges in Marketing a Paradigm Shift
Since the early beginnings people have been traveling and tourism industry has been always adapting to the social and technological development. In the era of digitalization, it needs to adapt again. Around 1.3 billion persons are traveling yearly around the world. Thus, a small change in this sector has a huge impact on the whole society. We propose a new paradigm, Tourism 4.0, appearing with the quest to unlock the innovation potential in the whole tourism sector. This will be done with the help of key enabling technologies from the Industry 4.0, such as Internet of Things, Big Data, Blockchain, Artificial Intelligence, Virtual Reality and Augmented Reality. By establishing a collaborative ecosystem involving local inhabitants, local authority, tourists, service providers and government, we can co-create an enriched tourism experience in both the physical and the digital world. With this, we can shift from tourist-centered focus to a tourism-centered focus around the local community. Who is the consumer in this new paradigm of tourism and what is the role of marketing in a paradigm shift? The chapter will analyze the current development and present the main shifts due to it
Orbital-dependent electron dynamics in Fe-pnictide superconductors
We report on orbital-dependent quasiparticle dynamics in EuFeAs, a
parent compound of Fe-based superconductors and a novel way to experimentally
identify this behavior, using time- and angle-resolved photoelectron
spectroscopy across the spin density wave transition. We observe two different
relaxation time scales for photo-excited d/d and d
electrons. While d/d electrons relax faster through the
electron-electron scattering channel, showing an itinerant character, d
electrons form a quasi-equilibrium state with the lattice due to their
localized character, and the state decays slowly. Our findings suggest that
electron correlation in Fe-pnictides is an important property, which should be
taken into careful account when describing the electronic properties of both
parent and electron-doped compounds, and therefore establish a strong
connection with cuprates
Towards ultrafast X-ray condensed matter physics with MHz repetition rate HHG sources
In recent years, an increasing number of ultrafast material science experiments are based on the use of table-top high-harmonic generation (HHG) lightsources [1,2]. Despite the huge success of these first experiments, a major drawback has been the limited repetition rate of these lightsources, in particular with respect to all types of photoemission experiments. Here, we combine newly developed high-repetition rate HHG sources [3,4] with state-of-the-art element-specific magneto-optical Kerr experiments. The chances and prospects for future ultrafast materials science experiments with these lightsources will be discussed
PHYSICS II - Exercises
The following script is the first part of selected exercises and examples from the topics of Hydrostatics and Hydrodynamics. They were collected during the academic year 2019/20 when I was holding Physics II tutorials for the study program Physics and Astrophysics I. level within the School of Science at the University of Nova Gorica. The source material I used is given in the Bibliography at the end. Hopefully, these exercise fill help in providing a more in-depth understanding of physical phenomena discussed during the lectures
Element-resolved study on the influence of a magnetic dopant on the exchange interaction in FePt on ultrashort timescales
In this study, we investigate the optically induced ultrafast demagnetization dynamics of a FePt alloy doped with Mn atoms on the characteristic timescale of the exchange interaction of a few femtoseconds. We use high harmonic generation with photon energies in the XUV to gain elemental resolution in a femtosecond magneto-optical Kerr-effect experiment [1] in transversal geometry. Following up on earlier experiments, which showed the importance of the exchange interaction in the demagnetization process in alloys [2,3], we see clear differences in the dynamical responses of the three elements Fe, Pt, and Mn. Our results suggest, that the exchange coupling between the magnetic moments of the FePt alloy and the Mn dopant changes on ultrashort timescales
The role of non-equilibrium dynamics in photo-induced phase transitions of correlated materials
We use femtosecond extreme-ultraviolet time- and angle-resolved photoelectron spectroscopy to study the ultrafast photo-induced suppression of the charge-density wave (CDW) in 1T-TiSe2. In the following non-equilibrium electron dynamics after femtosecond laser excitation, we see that hot-carrier multiplication is the primary driver for the ultrafast CDW suppression. As soon as the optically excited carriers have relaxed to a quasi-equilibrium hot Fermi-distribution electron gas, the CDW suppression stops. Theoretical calculations of the hot-carrier scattering processes and the screening properties further link the carrier multiplication to the observed CDW gap dynamics
Ultrafast Element-Specific Demagnetization in Alloys
The study of magnetism has long been an active area of interest for the scientific research, while also providing vast technological applications such as information storage. It was first observed in the middle of the 90s that irradiating a ferromagnetic material with an intense femtosecond laser pulse can result in a loss of magnetization occurring below one picosecond. Since then, the study of magnetism on these femtosecond timescales has been a field of growing interest, addressing the question of how fast can the magnetization modification occurs and what presents the fundamental limit of this speed. For the understanding of these experimental observations, a number of different models were proposed, although the responsible microscopic mechanisms are still under discussion. According to one group of models, the change in magnetic moment is due to the spin-flip mechanism occurring during scattering events between electrons and (quasi-)particles. An example of this is the so-called Microscopic Three-Temperature Model (M3TM). A different approach is employed by the Superdiffusive Spin Current Model, where the loss of magnetization is attributed to a flow of chargeless spin particles taking place after the laser excitation.
With the purpose to explore the magnetic characteristic of materials, a range of investigation methods has been developed. One of them relies on the exploitation of the Magneto-Optical Kerr Effect (MOKE) and an incorporation of femtosecond laser pulses in pump-probe configuration. In this way, part of the beam from the same laser system is used to optically excite the system (the pump), while another part takes a snapshot of it (the probe), thus allowing us to investigate the magnetization dynamics with a femtosecond temporal resolution. In the experimental part of the thesis, we apply this MOKE technique to explore the demagnetization dynamics of a ferromagnetic alloy consisting of iron and nickel, also called Permalloy. It is observed that the magnetization is suppressed (quenched) in the first few hundred femtoseconds. Part of the experiments were performed using visible light with different fluences of the pump. The most notable observation is that this alloy exhibits different demagnetization dynamics at lower and higher fluence. What we see is a transition from one-step (demagnetization followed by a recovery on a much longer timescale) to a two-step (demagnetization followed by another slower demagnetization step) magnetization process occurring with the increment of pump fluence. This behavior is predicted and reproduced by the M3TM, which is applied for a comparison between experiments and theory