11. Studentská vědecká konference fyziky pevných látek a materiálů (2022)

Contribution List

64. 100. výročí Dolejškova objevu série N

Přednáška zabývající se stým výročím Dolejškova objevu série N.

45. Deformation processes under the nanoindenter tip

Nanoindentation was developed as an alternative to traditional hardness and microhardness tests based on the penetration of a tip into the material under investigation. Decreasing the penetration depths down to submicrometer range brings many experimental and theoretical challenges. The contribution shows several examples, where the evolution of plastic zone and deformation modes under the...

37. Effect of molecular structure on liquid crystalline behaviour for chiral lactic acid derivatives

Liquid crystals are self-organizing materials that have great potential for practical applications. The relationship "molecular structure - mesomorphic properties" has not been fully established and understood despite numerous studies. We discuss a relatively broad subclass of calamitic chiral lactic acid derivatives and provide specific examples of effective tuning of their mesomorphic and...

40. Ga vacancies in GaN: challenge for theorists and experimentalists

Despite large spread of GaN-based devices in 1990s, several fundamental questions about GaN properties remain unanswered. One of them is a role or even a presence of Ga vacancies in GaN. According to the first-principle calculations, the Ga vacancy formation energy is too high for their presence in significant concentrations. However, this is in contradiction with experiments. In this work,...

54. Generalized inverse problems in resonant ultrasound spectroscopy

Resonant ultrasound spectroscopy (RUS) is one of the most precise and versatile methods used for the determination of elastic coefficients. The method is based on measurement of mechanical resonances of a solid body. However, determination of the elastic constants by RUS is an inverse problem so the experimentally obtained resonant frequencies cannot be directly recalculated into the elastic...

62. Jana2020 – the universe of crystallography in one software package

JANA is a crystallographic software developed to help users solve crystal structures from diffraction data. The first version of JANA software was developed in 1984 by Vaclav Petricek to solve modulated and composite structures from single crystal data. Over the years and versions (Jana94, Jana98, Jana2000, Jana2006 and Jana2020), the software has evolved to accept all types of diffraction...

36. K$_{(1-x)}$Li$_x$TaO$_3$ - krystal s neobvyklou dynamikou feroelektrického fázového přechodu

Za pomocí širokopásmové dielektrické spektroskopie, Ramanovy spektroskopie, generace druhé harmonické a měření pyroproudu byl potvrzen perkolační charakter feroelektrického (FE) fázového přechodu v krystalech K$_{(1-x)}$Li$_x$TaO$_3$. Tyto techniky umožnily studovat dielektrickou odezvu krystalu v oblasti 1 Hz – 20 THz a prozkoumat dynamiku měkkých fononových a relaxačních módů. Výsledky...

47. Localization of martensitic transformation in shape memory alloys: 3D spatial reconstruction by X-ray diffraction/scattering computed tomography.

The stress-induced martensitic transformation in polycrystalline NiTi-based shape memory alloys often tends to localize in bands on the macroscopic scale. In this contribution, we will present utilization of one recent tomographic technique - X-ray diffraction/scattering computed tomography (DSCT) - for spatial reconstruction of austenite–martensite transition zones in superelastic NiTi wires...

60. Magnetocrystalline anisotropy of Ni-Mn-Ga-Co-Cu tetragonal martensite

The martensites of Heusler alloys based on Ni-Mn-Ga exhibit magnetically induced reorientation resulting in giant field induced strain up to 12 % in Ni-Mn-Ga-Co-Cu with 4 at.% of Co and Cu. As the driving force of the phenomenon is the magnetocrystalline anisotropy (MCA), we studied the evolution of MCA in different tetragonal single crystalline Ni-Mn-Ga-Co-Cu and compared with pure Ni-Mn-Ga....

33. Metal Ion Exchange in Zn-Dependent S1 Nuclease: Effect on the Structure

S1 nuclease is an enzyme commonly used in biotechnology applications. Its activity depends on the presence of three Zn(II) ions in the active site. In this work, we examine the possibility of exchanging the natively present Zn(II) ions to Cd(II). EDTA-treated S1 nuclease was successfully crystallized in the presence of CdCl2. The anomalous signal from three different energies confirmed the...

44. Morphological and Structural Changes of Ceramic Powders during Plasma Spraying

Powders with spherical particles are utilized in various industries such as health, food, or in additive manufacturing due to their enhanced flow properties. Plasma spray spheroidization is an effective tool for manufacturing of such powders from angular or agglomerated powder feedstocks, namely thanks to its high feedstock throughputs. In this thesis, the formation process of spherical...

41. Numerical Study on Thermally Induced Birefringence in Yb:YAG Laser Rod: Power Output Optimisation

A traditional approach to study the birefringence induced under laser pumping is
presented. Numerical study of thermally induced birefringence was performed based
on material properties of Yb:YAG rod laser crystal in crystallographic orientation
[001]. New method introduced here is devoted to optimisation of relative output
intensity from the system containing a laser rod placed between...

43. Optimalizace depozičních parametrů tenkých vrstev vysokoteplotních supravodičů na bázi YBCO připravených pomocí IJD; Optimalization of IJD deposition parameters of high temperature superconductors thin films based on YBCO

Hlavním cílem této bakalářské práce byla optimalizace depozičních parametrů pro přípravu vysokoteplotních supravodičů na bázi YBCO pomocí metody IJD s přihlédnutím k využití v průmyslu. V teoretické části jsou vysvětleny základní principy samotné depoziční metody a analytických metod využitých pro studium nanesených vrstev.
V rámci experimentu bylo připraveno 6 různých vzorků ve dvou sériích....

56. Predikce krystalových struktur s pomocí experimentálních dat

Predikce krystalových struktur je metoda, při které se navrhují nové struktury látek či se vytváří modely látek, které se nepodařilo vyřešit jiným způsobem. Výpočty přesných hodnot energie, podle nichž se struktury predikují, však mohou být časově náročné, proto se v práci věnujeme dvěma způsobům, jak predikci urychlit: úpravami algoritmu hledajícího krystalovou strukturu; zapojením...

57. Preferred orientation of freshwater shells of the species Sinanodonta woodiana and Anodonta anatina studied by neutron and X-ray diffraction

Using neutron and X-ray diffraction, the texture of the prismatic and nacreous layer of several shells of the species Sinanodonta woodiana was studied and compared with the preferred orientation of the shells of the species Anodonta anatina. The shells of both molluscs were collected in freshwater streams in the Czech Republic. The neutronographic texture measurements were performed on the...

53. Příprava nanotyček ZnO na substrátech modifikovaných fokusovaným iontovým svazkem

Tato práce přináší nové možnosti pro úpravu morfologie a vlastností nanotyček při růstu metodou depozice z chemické lázně a pro studium vlivu různých reakčních podmínek na růst. To je velmi výhodné zejména pro výrobu polovodičových součástek, např. LD, solárních článků nebo piezoelektrických nanogenerátorů, jelikož pro různé součástky jsou vhodné různé nanotyčky. Pro možnosti studia a...

67. Quantum Hyperion HPC Cluster - Status Update 2022

A lot of work has been done on the new Quantum Hyperion cluster (obtained as part of the Quantum Technologies project at the faculty) in last year, mainly in the field of intra-cluster networking and parallel storage. This short talk is going to summarize the overview of what has been done and where are we currently also from the user point of view.

52. Quantum technologies

Aim of the presentation is to provide a brief overview of scientific fields and topics referred to by the collective term "Quantum Technologies", with the emphasis laid on the areas that are close to the research conducted at the Department of Solid State Engineering FNSPE CTU in Prague, and might be thus of interest in terms of determining its future direction.

51. Rekonstrukce Landauovské energie feroelastického chování slitiny Ni-Fe-Ga(Co)

Tento příspěvek popisuje sestrojení energetické funkce popisující chování feromagnetické slitiny s tvarovou pamětí Ni-Fe-Ga(Co) v rámci Landauovy teorie. Monokrystalický vzorek byl podroben tahové zkoušce a rezonanční ultrazvukové spektroskopii v širokém intervalu teplot. Z naměřených křivek závislosti napětí na deformaci byly odvozeny konstanty landauovské volné energie 4. řádu. Tato energie...

35. SHELIXIR: code development

The constant development of new experimental approaches goes hand-in-hand with the continuous improvement of data evaluation strategies, mainly software-based. When writing new software, the code writers should respect the needs of users, both experienced and novices. When possible, the software should serve universal purposes and use, decision strategies implemented, and novel metrics...

55. Spektroskopie s přechodovou mřížkou tenkých vrstev NiTi

NiTi is a shape memory alloy utilized in many applications thanks to its thermal stability, corrosion resistance and biocompatibility. In this work, surface waves propagation in thin epitaxial NiTi films is investigated with transient grating spectroscopy (TGS). It is demonstrated that the thin film thickness limits the amount of observable wave modes at given acoustic wavelength and...

34. Structural insight into antibiotic-inactivating enzyme from Stenotrophomonas maltophilia

Stenotrophomonas maltophilia is an opportunistic bacterial pathogen responsible for a serious number of infections globally. It exhibits broad antibiotic resistance that has been further extended via the acquisition of antibiotic-resistance genes and mutations [1]. We carried out a bioinformatic analysis of its sequenced genomes to investigate not yet characterised antibiotic-inactivating...

49. Study of the real structure of laser-cladded steel

The aim of this contribution is to describe the effects of laser additive manufacturing (cladding) on the real structure, microstructure, and mechanical properties of laser cladded H13 tool steel. Extensive experimental research combining X-ray, neutron and electron diffraction has been performed. Furthermore, the microstructure was described, the hardness and other mechanical properties were...

50. Superspace symmetry of Ni-Mn-Ga-based crystals

The discovery of aperiodic crystals (crystals where three-dimensional lattice periodicity is absent) initiated crystallographers’ journey into higher dimensions. Using (3+1)-dimensional superspace, we will introduce the world of incommensurate martensite structures with one-dimensional modulation and show how to deal with the lack of translational symmetry.

63. The misfit layer compound PbSVS2: a composite structure with twins

Transition metal dichalcogenides (TMD) have been attracting attention due to their promising use in photonic, biological, and chemical applications. As an alternative to the standard light-emitting devices (LEDs), which lacks the emission of chirally polarized light at room temperature, TMD semiconductors can be used to obtain controllable chiral LEDs. One of the configurations of chirally...

46. Thin films of CsPbBr$_3$ nanocrystals on scintillating wafers

There is a rising demand for new detectors with ultra-fast timing for the use of Time-Of-Flight measurements in medical imaging and high-energy physics. One way of tackling this challenge is a composite material of bulk inorganic scintillators with nanoscintillators exhibiting quantum confinement effect. In this work, thin films of CsPbBr$_3$ nanocrystals were prepared on various substrates...

39. Towards biomedical applications of Heusler alloys

Heusler alloys are alloys of three or more metal elements with specific atomic ordering that enables reaching properties very different from those of pure metals. Typically, the Heusler alloys can be ferromagnetic, despite of being composed of three non-magnetic elements. The Heusler ordering can also affect the lattice stability, leading to acoustic phonon condensation and diffusionless phase...

38. Ultrasonic characterization of inner defects in cold sprayed coatings

Pure Fe coatings were deposited by cold spraying onto Al substrates with machined notches. Scanning acoustic microscopy (SAM) was utilized to study the mechanical properties of Fe coatings around the notches, where an increased porosity was revealed by SEM. The resulting distributions of ultrasonic wave velocities and their attenuation show that the area affected by the non-perpendicular...

59. Understanding Antiphase Boundaries – Path to New Multiferroic Functionalities in Ni-Mn-Ga Magnetic Shape Memory Alloys

The presence of antiphase boundaries (APBs) can be expected in any chemically ordered compound. In Ni2MnGa, magnetic shape memory alloy, the transition between partly disordered B2’ and ordered L21 structure occurs above 1000 K and the transition is fast and weakly of the first order. Understanding the nature of APB is important as it affects the magnetic hysteresis and also magnetically...

61. Upřesňování jako nezbytný nástroj při studiu vazby mezi proteinem a ligandy

Rentgenová strukturní analýza umožňuje studovat vazby mezi ligandem a proteinem na atomární úrovni, čímž může nejen významně přispět k objasnění funkce studovaného proteinu, ale i identifikovat jeho potenciální inhibitory. Tato práce se věnovala dvěma komplexům ligandu s nukleasou ze Stenotrophomonas maltophilia. Především pak upřesňování strukturních modelů a vlivu upřesňování na nalezení...

66. Vliv teploty substrátu na vlastnosti tenkých YBCO vrstev připravených metodou IJD

Příprava tenkých vrstev vysokoteplotních supravodičů je velmi aktuální problematiku, protože se v současné době vysokoteplotní supravodiče stále častěji uplatňují v praxi a je potřeba optimalizovat jejich výrobu ve všech formách. Metoda Ionized Jet Deposition (IJD) by mohla být vhodný způsob jak tyto vrstvy připravovat v průmyslovém měřítku. V součastnosti je vyvíjen postup jak tyto vrstvy...

42. Využití neuronových sítí při tvorbě potenciálů pro molekulární dynamiku.

V posledních dekádách jsou neuronové sítě čím dál častěji skolňovaným tématem. Díky jejich schopnosti přesné a věrohodné predikce nacházejí uplatnění v mnoha oborech včetně materiálového inženýrství. Jedna z možností jejich využití se nachází v molekulární dynamice, která nabízí možnost simulovat časový vývoj velkých systému, nicméně její přesnost je značně omezená. V této práci se budeme...

65. Vývoj substrátů pro spektroskopii založenou na povrchem zesíleném Ramanově rozptylu

Spektroskopie založená na povrchem zesíleném Ramanově rozptylu (SERS) je vysoce citlivá metoda pro určování chemického složení. Principem je využití substrátů ve formě tenkých metalo-dielektrických nanostrukturovaných vrstev. V těsné blízkosti povrchu kovu dochází k řádovému nárůstu intenzity EM pole a tím i k zesílení Ramanova rozptylu na molekulách, které se zde nacházejí. Pro praxi je...

48. X-ray tomography – first experiences

In the spring of this year, an Xradia Versa 610 x-ray tomograph was installed in the Institute of Physics of the Academy of Sciences of the Czech Republic. In this post, I would like to summarize my first experiences with this equipment from common things to scientific samples. The device create a 3d object from thousands of x-ray images. For small objects, the size of one voxel (pixel in...