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The development of an x-ray method that used a grazing-incidence diffraction setup for the structural characterization of semiordered GaN nanorods is reported. The application of the method is demonstrated on a series of GaN nanorod samples to determine the mean size of the rods and their angular twist with respect to the crystalline substrate.

Diffraction method is used for examining the structure of polycrystalline [Ni.sub.3]N layers in periodic C/Ni multilayers, where the method is modulated by a standing wave created by the interference of the radiation. This method is used for analyzing the profiles of the crystallize sizes and strains in multilayers.

Phases with spontaneous time-reversal ( T ) symmetry breaking are sought after for their anomalous physical properties, low-dissipation electronic and spin responses, and information-technology applications. Recently predicted altermagnetic phase features an unconventional and attractive combination of a strong T -symmetry breaking in the electronic structure and a zero or only weak-relativistic magnetization. In this work, we experimentally observe the anomalous Hall effect, a prominent representative of the T -symmetry breaking responses, in the absence of an external magnetic field in epitaxial thin-film Mn 5 Si 3 with a vanishingly small net magnetic moment. By symmetry analysis and first-principles calculations we demonstrate that the unconventional d-wave altermagnetic phase is consistent with the experimental structural and magnetic characterization of the Mn 5 Si 3 epilayers, and that the theoretical anomalous Hall conductivity generated by the phase is sizable, in agreement with experiment. An analogy with unconventional d-wave superconductivity suggests that our identification of a candidate of unconventional d-wave altermagnetism points towards a new chapter of research and applications of magnetic phases., (© 2024. The Author(s).)

The morphology and crystal structure of Pt films grown by pulsed laser deposition (PLD) on yttria-stabilized zirconia (YSZ)at high temperatures Tg = 900 °C was studied for four different film thicknesses varying between 10 and 70 nm. During the subsequent growth of the capping layer, the thermal stability of the Pt was strongly influenced by the Pt film's thickness. Furthermore, these later affected the film morphology, the crystal structure and hillocks size, and distribution during subsequent growth at Tg = 900 °C for a long duration. The modifications in the morphology as well as in the structure of the Pt film without a capping layer, named also as the as-grown and encapsulated layers in the bilayer system, were examined by a combination of microscopic and scattering methods. The increase in the thickness of the deposited Pt film brought three competitive phenomena into occurrence, such as 3D-2D morphological transition, dewetting, and hillock formation. The degree of coverage, film continuity, and the crystal quality of the Pt film were significantly improved by increasing the deposition time. An optimum Pt film thickness of 70 nm was found to be suitable for obtaining a hillock-free Pt bottom electrode which also withstood the dewetting phenomena revealed during the subsequent growth of capping layers. This achievement is crucial for the deposition of functional bottom electrodes in ferroelectric and multiferroic heterostructure systems.

The structure and the chemical composition of individual layers as well as of interfaces belonging to the two heterostructures M1 (BaFe 12 O 19 /YbFeO 3 /YSZ) and M2 (YbFeO 3 /BaFe 12 O 19 /YSZ) grown by pulsed laser deposition on yttria-stabilized zirconia (YSZ) substrates are deeply characterized by using a combination of methods such as high-resolution X-ray diffraction, transmission electron microscopy (TEM), and atomic-resolution scanning TEM with energy-dispersive X-ray spectroscopy. The temperature-dependent magnetic properties demonstrate two distinct heterostructures with different coercivity, anisotropy fields, and first anisotropy constants, which are related to the defect concentrations within the individual layers and to the degree of intermixing at the interface. The heterostructure with the stacking order BaFe 12 O 19 /YbFeO 3 , i.e., M1, exhibits a distinctive interface without any chemical intermixture, while an Fe-rich crystalline phase is observed in M2 both in atomic-resolution EDX maps and in mass density profiles. Additionally, M1 shows high c -axis orientation, which induces a higher anisotropy constant K1 as well as a larger coercivity due to a high number of phase boundaries. Despite the existence of a canted antiferromagnetic/ferromagnetic combination (T < 140 K), both heterostructures M1 and M2 do not reveal any detectable exchange bias at T = 50 K. Additionally, compressive residual strain on the BaM layer is found to be suppressing the ferromagnetism, thus reducing the Curie temperature (Tc) in the case of M1. These findings suggest that M1 (BaFe 12 O 19 /YbFeO 3 /YSZ) is suitable for magnetic storage applications.

A prominent characteristic of 2D magnetic systems is the enhanced spin fluctuations, which reduce the ordering temperature. We report that a magnetic field of only 1000th of the Heisenberg superexchange interaction can induce a crossover, which for practical purposes is the effective ordering transition, at temperatures about 6 times the Néel transition in a site-diluted two-dimensional anisotropic quantum antiferromagnet. Such a strong magnetic response is enabled because the system directly enters the antiferromagnetically ordered state from the isotropic disordered state, skipping the intermediate anisotropic stage. The underlying mechanism is achieved on a pseudospin-half square lattice realized in the [(SrIrO 3 ) 1 /(SrTiO 3 ) 2 ] superlattice thin film that is designed to linearly couple the staggered magnetization to external magnetic fields by virtue of the rotational symmetry-preserving Dzyaloshinskii-Moriya interaction. Our model analysis shows that the skipping of the anisotropic regime despite finite anisotropy is due to the enhanced isotropic fluctuations under moderate dilution.

We have studied the effect of platinum underlayer for two deposited thicknesses on the microstructure, crystalline quality, morphology, chemical composition, and magnetic properties as well as magnetic domain formation of BaFe 12 O 19 (BaM) grown on YSZ(111) by pulsed laser deposition (PLD). We found that PLD platinum deposited with a thickness of 25 nm cannot withstand the dewetting phenomenon occurring during the subsequent BaM layer growth. A smooth and continuous Pt underlayer that possesses a sharp interface and omits the intermixing between the BaM and substrate was successfully achieved for a deposited Pt film thickness of 75 nm. Independent of the thickness of the deposited Pt layer, the c -axis orientation as well as coercivity Hc and the anisotropy H A fields were significantly improved due to a remarkable improvement of lattice mismatch in comparison with the BaM layer grown without a Pt underlayer on YSZ(111). By applying high-resolution X-ray diffraction, scanning and transmission electron microscopy (SEM/TEM), and atomically resolved scanning TEM imaging combined with energy-dispersive X-ray spectroscopy, as well as atomic and magnetic force microscopy, a comprehensive investigation of both structure and chemical composition of the deposited BaM films and their interfacial regions was performed. This study aimed to correlate the enhancement of the overall magnetic properties and of the local spin magnetic domain orientation with the modification of BaM microstructure and chemical composition at the nanometer scale due to the Pt underlayer. Finally, we attempted to understand the mechanisms that control the magnetic properties of these BaM films in order to be able to tailor them.

The number of atomic layers confined in a two-dimensional structure is crucial for the electronic and magnetic properties. Single-layer and bilayer J&#95;{eff}=1/2 square lattices are well-known examples where the presence of the extra layer turns the XY anisotropy to the c-axis anisotropy. We report on experimental realization of a hybrid SrIrO&#95;{3}/SrTiO&#95;{3} superlattice that integrates monolayer and bilayer square lattices in one layered structure. By synchrotron x-ray diffraction, resonant x-ray magnetic scattering, magnetization, and resistivity measurements, we found that the hybrid superlattice exhibits properties that are distinct from both the single-layer and bilayer systems and cannot be explained by a simple addition of them. In particular, the entire hybrid superlattice orders simultaneously through a single antiferromagnetic transition at temperatures similar to the bilayer system but with all the J&#95;{eff}=1/2 moments mainly pointing in the ab plane similar to the single-layer system. The results show that bringing monolayer and bilayer with orthogonal properties in proximity to each other in a hybrid superlattice structure is a powerful way to stabilize a unique state not obtainable in a uniform structure.

We report on the epitaxial strain-driven electronic and antiferromagnetic modulations of a pseudospin-half square-lattice realized in superlattices of (SrIrO&#95;{3})&#95;{1}/(SrTiO&#95;{3})&#95;{1}. With increasing compressive strain, we find the low-temperature insulating behavior to be strongly suppressed with a corresponding systematic reduction of both the Néel temperature and the staggered moment. However, despite such a suppression, the system remains weakly insulating above the Néel transition. The emergence of metallicity is observed under large compressive strain but only at temperatures far above the Néel transition. These behaviors are characteristics of the Slater-Mott crossover regime, providing a unique experimental model system of the spin-half Hubbard Hamiltonian with a tunable intermediate coupling strength.

Fundamental control of magnetic coupling through heterostructure morphology is a prerequisite for rational engineering of magnetic ground states. We report the tuning of magnetic interactions in superlattices composed of single and bilayers of SrIrO 3 inter-spaced with SrTiO 3 in analogy to the Ruddlesden-Popper series iridates. Magnetic scattering shows predominately c-axis antiferromagnetic orientation of the magnetic moments for the bilayer, as in Sr 3 Ir 2 O 7 . However, the magnetic excitation gap, measured by resonant inelastic x-ray scattering, is quite different between the two structures, evidencing a significant change in the stability of the competing magnetic phases. In contrast, the single layer iridate hosts a more bulk-like gap. We find these changes are driven by bending of the c-axis Ir-O-Ir bond, which is much weaker in the single layer, and subsequent local environment changes, evidenced through x-ray diffraction and magnetic excitation modeling. Our findings demonstrate how large changes in the magnetic interactions can be tailored and probed in spin-orbit coupled heterostructures by engineering subtle structural modulations.

The evolution of local ferroelectric lattice distortions in multiferroic Ge 1- x Mn x Te is studied by x-ray diffraction, x-ray absorption spectroscopy and density functional theory. We show that the anion/cation displacements smoothly decrease with increasing Mn content, thereby reducing the ferroelectric transition from 700 to 100 K at x = 0.5, where the ferromagnetic Curie temperature reaches its maximum. First principles calculations explain this quenching by different local bond contributions of the Mn 3 d shell compared to the Ge 4 s shell in excellent quantitative agreement with the experiments.

Background: Photodynamic therapy (PDT) is a clinically-accepted approach for the therapy of many types of cancer. This study focused on the treatment of mammarian carcinoma by topical administration of hydroxyl-aluminium phthalocyanine (AlOH-PC), compared to a clinically-approved photosensitizer (Metvix, Galderma & PhotoCure ASA, Inc., Oslo, Norway)., Materials and Methods: MDA-MB 231 cells were subcutaneously injected into the right flank of athymic nude mice. Mice with grown tumours were used for in vivo efficacy studies. Different doses of liposomal AlOH-PC were applied to determine the most effective dose. In later studies, Metvix or our liposomal-AlOH-PC gel formula were used. Topical application of photosensitizers was followed by the PDT irradiation at 600-700 nm (635 nm peak). Tumour growth was measured three times weekly., Results: Therapeutic studies revealed that AlOH-PC treatment led to complete tumour remission in 90% (9/10) of experimental animals, whereas usage of the commercially available Metvix only postponed the tumour growth. Moreover, usage of liposomal AlOH-PC shortened the time allowed between the application of the photosensitizer and light exposure: for Metvix, hours are usually needed, while the tested liposomal AlOH-PC showed remarkable outcomes after only 10 min., Conclusion: Liposomal AlOH-PC gel appears to be potentially suitable for PDT of mammarian carcinoma.

Colorectal cancer is one of the most common cancers in Europe and North America and it is the most common gastrointestinal carcinoma. The population in the Czech Republic has a higher incidence of colorectal carcinoma compared to other countries. Efforts are underway to develop better screening strategies and novel therapies to improve patient survival rates. Despite all efforts, colorectal cancer remains one of the leading causes of death from cancer. Photodynamic therapy (PDT) is an established modality for the treatment of various diseases. The PDT procedure involves the administration of a photosensitizer followed by illumination. The anti-tumor effects result from direct killing of malignant cells, shutting down of the tumor's vasculature, and the promotion of an immune response. In our experiment, we examined the effects of phototherapy with disulfonated hydroxyaluminum phthalocyanine (Al(OH)S2Pc) on the growth of colorectal carcinoma cells, in an effort to offer a new treatment modality for patients with this disease.

Photodynamic therapy (PDT) has been developed in recent years as a new modality for the treatment of various neoplastic and non-neoplastic lesions. Although the method of combining light with photosensitizers for treatment has been around for a century, further understanding has been evolved over the past decades. The method is based on the phenomenon involving the combination of photosensitizer and light. Neither drug nor light alone are effective as therapeutic agents. The antitumour effects result from direct cell damage, destruction of tumor vasculature and activation of a nonspecific immune response. The more accepted use of PDT is still restricted for ophthalmology, dermatology and treatment of some stages of esophageal, lung and urinary bladder cancer. In our experiments, the effect of phototherapy with disulfonated hydroxyaluminium phthalocyanine (Al(OH)S2Pc) and photofrin (control group) on the growth of human colorectal carcinoma on nude mice was studied. We chose colorectal carcinoma, because the Czech population has the highest incidence and it is still increasing. We try to offer a new possibility of treatment for patients with this severe disease.