Magnetism and superconductivity seminar

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March 2023

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6 Journal Club National Ignition Facility surpasses long-awaited fusion milestone 12:00 Zoom Piotr Deuar, Instytut Fizyki PAN Date : 06 03 2023	7 Seminarium Rentgenowskie Synthesis, structure and possible application of selected salicylidene derivatives for detection of metal ions 10:30 Instytut Fizyki PAN, Warszawa Schiff bases are well-known compounds with versatile applications in analytical chemistry, catalysis, food and dye industry. They also possess many biological activities such as antibacterial, antifungal, antitumor etc. From a chemical perspective the synthesis of imine derivatives is one of the easiest in the whole synthesis repertoire. Very important feature of these compounds is also their ability to form complexes with metal ions. The self-templating process is frequently observed when obtaining new coordination compounds, which accelerates the reaction time and lowers the production costs. This fits in the trend of sustainable chemistry.The aim of this talk is to present the synthesis and physicochemical properties of selected d- and f-electron complexes with Schiff base derivatives having 5-bromo-3-methoxysalicylidene moiety and a stiff or a flexible amine part. I will also try to show a possible application of these compounds for detection of metal ions. Condensed Matter Physics Seminar Interplay of magnetism and superconductivity on Josephson junction 14:00 Institute of Physics , Warsaw , Poland Two superconductors held together by a thin layer of insulator allow the flow of supercurrent induced by the phase difference of the Cooper pair wave functions. This effect was predicted by B. Josephson and it has found a number of practical applications (e.g. in SQUID interferometers for extremely sensitive detection of magnetic fields). It has been shown more recently that tunneling of Cooper pairs also occurs through a single atom or a molecule due to the formation of bound states induced by multiple Andreev reflections. The direction and intensity of the Josephson current under such conditions are determined by the competition of the superconducting proximity effect with the Coulomb repulsion (leading to the so-called "zero-pi transition").The prospect of using the Josephson effect seems also possible in planar junctions, where the superconductors are separated by a thin metallic layer with a width of the order of micrometers. The cooperation of the proximity effect and Rashba type Date : 07 03 2023	8 Seminarium z Magnetyzmu i Nadprzewodnictwa Huge Dzyaloshinskii-Moriya interactions in Re/Co[n]/Pt thin films 10:00 Zoom - Instytut Fizyki PAN, Warszawa In this work, we study the Dzyaloshinskii-Moriya interaction (DMI) in the modeled Re/Co[n]/Pt chiral multilayered system using DFT calculations and report its interfacial and additive character. DMI is an antisymmetric indirect exchange interaction occurring between two spins Si and Sj. It arises also in the systems with broken inversion symmetry e.g. at the interfaces [1], in the presence of spin-orbit coupling. In particular, it is expected in heavy metal/ferromagnet asymmetric layered structures. This interaction is fundamental for the appearance of complex magnetic structures, e.g. skyrmions which are promising for the industry of spintronic applications that offer ultra-small, ultrafast, and low power devices. The control of the DMI strength in multilayered structures allows us to manipulate the different sizes and stability of these magnetic objects [2]. The total DMI strength (dtot[meV]) in the Re/Co[n]/Pt chiral multilayered system was calculated from the difference in energy between clockwise and anticlockwise Seminarium z Fizyki Biologicznej i Bioinformatyki Intramolecular mechanisms in photochromic organic molecules 15:15 Zoom - Instytut Fizyki PAN, Warszawa Date : 08 03 2023	9	10	11	12
13 Seminarium Fotofizyki i Spektroskopii Molekularnej Photochemical Hydrogen Storage with Hexaazatrinaphthylene 11:00 Instytut Fizyki PAN, Warszawa Climate warming and instabilities of fossil fuels supply make hydrogen a very desired energy carrier of the future. However, although a huge effort was devoted to development of hydrogen generation and storage methods, the current hydrogen technologies have still significant drawbacks. In the seminar an alternative approach to hydrogen generation and storage will be presented, with Proton-Coupled Electron Transfer (PCET), a process ubiquitous in nature that underpins energy conversion in chemistry and biology, as an engine of energy conversion. It will be shown that using Hexaazatrinaphthylene (HATN) as the photocatalyst, hydrogen atom can be abstracted from an alcohol molecule and stored on HATN. In this photochemical process, the energy of the absorbed photon is converted into the chemical energy of photoproducts. Journal Club A computing hardware approach aspires to emulate the brain 12:00 Zoom Midhun Mohan Anila, Instytut Fizyki PAN Date : 13 03 2023	14 Seminarium Rentgenowskie Fabrication of micro and nanostructures from crystals of topological insulators 10:30 Instytut Fizyki PAN, Warszawa Bismuth chalcogenides belong to the group of materials that can make future electronic devices far more powerful than today. However, nanostructurization of those materials is still a challenging process, as the quality of the structure surface will affect the material behavior. Our research is centered on defects induced in chalcogenides (Bi2Se3 and Bi2Te3) by the structurization process using Focused Ion Beams, by means of XAS, TEM and magnetoresistance studies. The fundamental goal of the study is to optimize the parameters of lithography processes (beam current, kinetic energy of ions, time of exposure, etc.) in order to keep the minimal desired size and shape of the nanostructures and preserve topological insulators properties by minimizing the damage in the surface states induced by the impinging ions. Theoretical Physics Seminar MDPD Simulations of liquid thread break-up and formation of droplets 12:00 Instytut Fizyki PAN Luis Carnevale da Cunha, Instytut Fizyki PAN Condensed Matter Physics Seminar Liquid quantum droplets in Bose-Bose mixtures 14:00 Institute of Physics P.A.S., Warsaw , Poland Atomic Bose-Einstein condensate is a gaseous ultradilute, ultracold system confined in space by external fields. Mixture of two such atomic condensates might lead, under certain conditions, to formation of an exotic quantum liquid taking form of a self-bound droplet - no external trap is needed to keep the atoms together. Binding energy of the droplet is provided by quantum fluctuations, the zero point energy of collective excitations of the system. In the first part of my talk I describe discovery of quantum droplets and explain a mechanism of their formation. In the second part, I will focus on a scattering of two droplets and interpret the scattering process in terms of double Josephson junction physics. Link to lecture video Date : 14 03 2023	15 Seminarium z Magnetyzmu i Nadprzewodnictwa Wpływ ciśnienia hydrostatycznego na separację faz magnetycznych i efekt "exchange bias" w złożonych materiałach tlenkowych z rodziny (La,Ba)FeO3 10:00 Zoom - Instytut Fizyki PAN, Warszawa W złożonych materiałach tlenkowych z rodziny (La,Ba)FeO3, krystalizujących w strukturze perowskitu zaobserwowano silny efekt indukowanej oddziaływaniami wymiennymi anizotropii jednokierunkowej (ang. exchange bias) [1]. Jego głównym przejawem jest przesunięcie pętli histerezy magnetycznej względem początku układu współrzędnych. W pracy [1] pokazano, jak kombinacja ciśnienia chemicznego, wynikającego z podstawienia lantan-bar oraz zewnętrznego pola magnetycznego może przyczyniać się do osłabiania lub wzmacniania zjawiska exchange bias, kosztem fazy ferromagnetycznej w związkach z rodziny LaxBa1-xFeO3 (x = 0,125; 0,25; 0,33). Na seminarium zostaną zaprezentowane wyniki wpływu ciśnienia hydrostatycznego - jako dodatkowego stopnia swobody - na parametry opisujące efekt "exchange bias". [1] I. Fita, A. Wiśniewski, R. Puźniak i inni, Phys. Rev. B 95, 134428 (2017) Date : 15 03 2023	16	17	18	19
20 Journal Club On the Law of Distribution of Energy in the Normal Spectrum 12:00 Zoom Hubert Dunikowski, Instytut Fizyki PAN Date : 20 03 2023	21 Theoretical Physics Seminar Tracing a quantum particle - an introduction to repeated measurements (continuation) 12:00 Instytut Fizyki PAN Filip Gampel, Instytut Fizyki PAN Date : 21 03 2023	22 Seminarium z Magnetyzmu i Nadprzewodnictwa Niezwykła dynamika ferroelektrycznego przejścia fazowego w domieszkowanym kwantowym paraelektryku K1-xLixTaO3 10:00 Zoom - Instytut Fizyki PAN, Warszawa Przedstawione zostaną rezultaty badań domieszkowanego jonami litu Li, tantalanu potasowego K1-xLixTaO3 (KLT-x), w którym dla x > 0,022 następuje przejście do stanu ferroelektrycznego. KTaO3 jest jednym z najlepiej poznanych, tzw. kwantowych paraelektryków.Zbadaliśmy zarówno liniowe jak i nieliniowe właściwości dielektryczne, wykorzystując szerokopasmowe badania dielektryczne oraz spolaryzowaną spektroskopię Ramana w zakresie temperatur 4,2-300 K, monokryształów KLT-0.043 i KLT-0.08, w których zachodzi przemiana ferroelektryczna pierwszego rodzaju odpowiednio w TC ≈ 50 K i TC ≈ 109 K. Przejście fazowe nie jest typu przesunięcia, ponieważ miękki mod mięknie znacznie słabiej, ale nie jest też typowe dla przejścia typu porządek-nieporządek. W naszych badaniach zmierzyliśmy i dopasowaliśmy widma dielektryczne do wartości częstotliwości równej 1013 Hz. Obserwujemy trzy aktywowane termicznie relaksacje Cole'a-Cole'a, które zachowują się zgodnie z prawem Arrheniusa lub Vogel-Fulchera. Dwie relaksacje na wyższych Seminarium z Fizyki Biologicznej i Bioinformatyki The mechanism of microtubule-pair sliding driven by kinesin-1 in vitro 15:15 Zoom - Instytut Fizyki PAN, Warszawa Date : 22 03 2023	23	24	25	26
27 Journal Club A seismometer maps Mars’s anatomy 12:00 Zoom Abdul Khaliq, Instytut Fizyki PAN Date : 27 03 2023	28 Konwersatorium Genetic variation - sources and consequences 15:15 online prof. dr hab. Marek Figlerowicz, Instytut Chemii Bioorganicznej PAN Date : 28 03 2023	29 Seminarium z Magnetyzmu i Nadprzewodnictwa Charge and heat transport through a quantum dot: two novel aspects 10:00 Zoom - Institute of Physics PAS, Warsaw To view the recording of the talk, please contact Prof. Andrzej Szewczyk: szewc@ifpan.edu.pl Nanostructures with quantum dots are still an active area of experimental and theoretical research. In the talk I shall discuss charge and heat transport through an interacting quantum dot in two situations of interest. In the first case we address the following question: if the local interactions between electrons on the quantum dot are important, one should also observe an effect of the so called “correlated” hopping meaning that the probability amplitude for the tunneling of a spin σ electron onto the dot should depend on the presence of an electron with opposite spin (-σ). We look at the influence of the “correlated hopping” on various transport characteristics in the two terminal device. The second case of interest is the observation that in the four terminal nanostructure in a cross geometry the currents may flow along the biased electrodes or perpendicular to them. We are interested in the rectification properties in such a geometry. By rectification we mean here the difference between the currents with forward and reversed bias. To observe the rectification, one must break two mirror symmetries of the device in the linear regime, whereas breaking a single mirror symmetry is enough Date : 29 03 2023	30	31

Seminarium z Magnetyzmu i Nadprzewodnictwa

Altermagnetism from a strong-coupling perspective

02-04-2025 10:00 - 11:00

Venue

Institute of Physics PAS, Room 203, Building I

This email address is being protected from spambots. You need JavaScript enabled to view it.

Website

https://www.ifpan.edu.pl

Speaker

Dr. hab. Krzysztof Wohlfeld, prof. UW

Affiliation

University of Warsaw

Link

https://zoom.us/j/95184359207?pwd=Y2RTNmMrbHRXVElFVkZnWkFVbkpxdz09

Sala

Room 203, Building I

Attachment

on3-2025-04-02-eng

.doc

To view the recording of the talk, please contact Prof. Andrzej Szewczyk: This email address is being protected from spambots. You need JavaScript enabled to view it.

Recently, a new form of magnetism has been proposed -- so-called altermagnetism. While altermagnetism has mostly been discussed within the itinerant picture, here I would like to provide a brief overview of three important aspects related to altermagnetism in the strong-coupling limit. First, I will discuss how to search for materials that should show altermagnetic properties in the strong coupling limit [1]. Next, I will explore whether there is a way to observe altermagnetism in strongly correlated copper oxides -- i.e. the parent compounds to high-temperature superconductors [2]. Last but not least, I will show that strongly coupled altermagnets should show spin-momentum dependent quasiparticle damping in ARPES [3].

[1] V. Leeb, A. Mook, L. Šmejkal, and J. Knolle, Phys. Rev. Lett. 132, 236701 (2024); K. Wohlfeld, M. Daghofer, A. M. Oles, EPL 96, 27001 (2011).
[2] Y. Li, V. Leeb, K. Wohlfeld, R. Valentí, J. Knolle, arXiv:2412.11922.
[3] M. Daghofer, K. Wohlfeld, J. van den Brink (to be submitted, 2025); K. Wohlfeld, A. M. Oleś, P. Horsch, PRB 79, 224433 (2009).

The lecture will be in Polish on-site in room 203. ZOOM transmission will be available too.

Zoom information.

List of Dates (Page event details)

02-04-2025 10:00 - 11:00

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