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3 pages, 3 figures. ; The low ac- and dc-field magnetic susceptibilities of hexagonal YbMnO3 single crystal have been measured along the ab plane and along the c axis (Xab,Xc). The antiferromagnetic Néel temperature TN is well signaled by a cusp in the temperature dependence of Xc but no features are visible in Xab. A remarkable anisotropy of paramagnetic susceptibility and the extrapolated Curie–Weiss temperature are observed and related to the quasibidimensional magnetic structure of YbMnO3. Below TN magnetic irreversibility sets, reflecting the presence of a weak ferromagnetic response. Possible scenarios for the origin of the weak ferromagnetism are discussed. ; This work has been supported by CSIC/BAS Project No. 2005BG0016. Financial support by the MEC of the Spanish Government (Project No. NAN2004-9094-C03, MAT2005- 5656-C04, and Nanoselec CSD 2007-00041), by Bulgarian Science Fund (Project No. BYX-308), and by the European Union (Projects MaCoMuFi: FP6-03321 and FEDER)is also acknowledged. ; Peer reviewed

Abstract
Germanium (Ge) films were heteroepitaxially grown on flexible, large-area, single-crystal-like metallic substrates. Multiple, heteroepitaxial, buffer layers of nanoscale dimensions were deposited on the triaxially textured, single-crystal-like, thermo-mechanically processed Ni–W alloy substrates. Ge films were deposited on a CeO2-terminated, heteroepitaxial buffer stack on the metallic substrate using electron beam evaporation. X-ray diffraction θ–2θ scans showed a very strong Ge (400) peak and the full width at half-maximum (FWHM) of the Ge (400) rocking curve was 0.93°. The Ge (111) ϕ-scan showed a FWHM value ∼4°. Based on the X-ray ω-scan, ϕ-scan and (111), (110), and (001) X-ray pole-figures, the Ge film deposited on the flexible, metallic substrate had a cube-on-cube heteroepitaxial relationship with the single-crystal-like metallic substrate. Reflection-high-energy-diffraction (RHEED) patterns from the Ge layer was streaky indicative of a smooth and essentially single-crystal-like Ge film. Cross-section TEM examination revealed a sharp interface between the Ge film and the topmost buffer layer, CeO2, with a low defect density. The CeO2 layer serves as a highly compliant layer that modulates its lattice parameter to attain excellent lattice-matching to the heteroepitaxial Ge layer. Ge films grown on these flexible metal substrates exhibited electron mobilities in the range of 175–250 cm2V–1s–1. Such single-crystal-like semiconductor films on low-cost, flexible, large-area, scalable, single-crystal-like metallic substrates could potentially enable high-performance electronic devices for a range of applications.

The Stockbargard – Bridgman method yielded single crystals Mn0.99Fe0.01As. The effect of an external magnetic field with an intensity of up to 10 T on phase transitions in the single crystal Mn0.99Fe0.01As is studied. It is established that the magnetostructural phase transition in Mn0.99Fe0.01As is accompanied by a change in the entropy ΔSm, which is due to the transformation of the crystal structure. At temperatures above the temperature of the magnetostructural transition Tu = 290 K, the existence of an unstable magnetic structure is obtained. The magnetocaloric characteristics of the material under study are determined by an indirect calculation method based on the Maxwell thermodynamic relations and the Clapeyron – Clausius equation.

Hexagonal manganites, such as h-LuMnO3, are ferroelectric and have a narrow electronic band gap of ≈1.5eV. Here we report on the photoresponse of h-LuMnO3 single crystals. It is found that the short circuit photocurrent density (Jsc) and the open circuit voltage (Voc) are dependent on the direction of the polarization plane of a linearly polarized impinging light. Its angular dependence indicates the contribution of bulk photovoltaic effect to the short circuit photocurrent. It is also observed that a switchable drift photocurrent, originating from the depoling field of the ferroelectric and thus tunable (<10%) by its polarization direction, also contributes to Jsc. Although its presence precludes accurate determination of the bulk photovoltaic tensor elements and Glass coefficients, some bounds can be established. The Glass coefficients are found to be significantly larger than those obtained in BiFeO3. We argue that the smaller band gap of h-LuMnO3, its distinctive bipyramidal crystal field, and electronic configuration (3d4 vs 3d5), account for the difference and suggest a path towards ferroelectrics of higher photoconversion efficiency. ; Financial support from the Spanish Ministry of Science, Innovation and Universities, through the "Severo Ochoa" Programme for Centers of Excellence in R&D (FUNFUTURE CEX2019-000917-S), PID2020-118479RBI00 (AEI/FEDER, EU) (AEI/FEDER, EU), and PID2019- 107727RB-I00 (AEI/FEDER, EU) projects, and from Generalitat de Catalunya (2017 SGR 1377) is acknowledged. I.F. acknowledges RyC Contract RYC-2017-22531. Project supported by a 2020 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation. The theoretical component of this work (A.M.S. and A.M.R.) was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award No. DE-FG02-07ER46431. Computational support was provided by the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy, Office of Science User Facility located at Lawrence Berkeley National Laboratory, operated under Contract No. DE-AC02- 05CH11231.The experimental and theoretical contributions of Y.S. are financially supported by China Scholarship Council (CSC), respectively with No. 201806410010. The work of Y.S. has been done as a part of her Ph.D. program in Materials Science at Universitat Autònoma de Barcelona. ; With funding from the Spanish government through the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000917-S). ; Peer reviewed

WTe2 and MoTe2 single crystals were grown, and their electrical resistivity in the temperature range from 80 K to 300 K, optical properties at room temperature in the spectral range of 0.17-5.0 eV were studied as well as theoretical calculations of the electronic structure were performed. It is shown that the temperature dependence of the electrical resistivity of orthorhombic WTe2 has a metallic type with resistivity value of (0.5-1) mOhmcm, while hexagonal MoTe2 has a semiconductor one and resistivity value (0.5-1) Ohmcm, which is three orders of magnitude larger than the resistivity of WTe2. Optical properties indicated that there is no contribution from free carriers in the entire spectral range studied. The calculated densities of the electronic states of MoTe2 and WTe2 showed the presence of a bunch of the molybdenum and tungsten electronic states in a wide energy interval with strong admixing of tellurium states. In the WTe2 compound, the larger number of the electronic states is located near the Fermi energy, characterizing a more metallic state in this compound as compared to MoTe2. © Published under licence by IOP Publishing Ltd. ; Government Council on Grants, Russian Federation: 02, 211 ; Russian Foundation for Basic Research, RFBR: 17-52-52008 ; Ministry of Education and Science of the Russian Federation, Minobrnauka: АААА-А18-118020190098-5 ; The research was carried out within the state assignment of Ministry of Education and Science of the Russian Federation (theme "Spin" No. АААА-А18-118020290104-2 and theme "Electron" No. АААА-А18-118020190098-5), supported in part by RFBR (Project No. 17-52-52008) and the Government of Russian Federation (Decree No. 211, Contract No. 02.A03.21.0006).

A single crystal of a topological Weyl semimetal WTe2 was grown and its electrical resistivity and galvanomagnetic properties (magnetoresistivity and the Hall effect) were investigated in detail in the temperature range from 1.8 K to 300 K and in magnetic fields of up to 9 T. © Published under licence by IOP Publishing Ltd. ; The research was carried out within the state assignment of Ministry of Education and Science of the Russian Federation (theme "Spin", No. АААА-А18-118020290104-2), supported in part by RFBR (Project No. 20-32-90069) and the Government of Russian Federation (Decree No. 211, Contract No. 02.A03.21.0006).

In this study, the influuence from crystal orientation on the thermomehanical fatigue (TMF) behaviour of the recently developed single-rystal superalloy STAL-15 is considered, both from an experimental and a nite element (FE) perspective. Experimental results show that there is a strong inuence from the elastic stiffness, with respect to the loading direction, on the TMF life. However, the results also indicate that the number of active slip planes duringdeformation inuence the TMF life, where specimens with a higher number of active slip planes are favoured compared to specimens with fewer active slip planes. The higher number of active slip planes results in a more widespread deformation compared to a more conentrated deformation when only one slip plane is active. Deformation bands with smeared and elongated γ-precipitates together with deformation twinning were found to be major deformation mechanisms, where the twins primarily were observed in specimens with several active slip planes. From an FE-perspective, therystal orientation with respect to the loading direction is quantied and adopted into a framework which makes it possible to describe the internal crystallographic arrangement and its entities in a material model. Further, a material model which incorporates the crystalorientation is able to predict the number of slip planes observed from microstructural observations, as well as the elasticstiness of the material with respect to the loading direction. ; On the day of the defence day the status of this article was Manuscript . The work has been financially supported by Siemens Industrial Turbomachinery AB in Finspang, Sweden, and the Swedish Energy Agency, via the Research Consortium of Materials Technology for Thermal Energy Processes, Grant no. KME-702. In addition, the support from the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU #2009-00971) is also acknowledged.

We have studied a dense domain structure (DDS) appearing during polarization reversal in rhombohedral (111)-cut lead magnesium niobate-lead titanate single crystals. The complicated shape of the switching current was explained by means of non-uniform motion of the boundary between the DDS and c-domains using comparative analysis of the optical current and kinetic map. 2D-vector piezoresponse force microscopy revealed that DDS represented needle-like a-domains inside the a-domains with different vertical orientations of spontaneous polarization. © 2020 Author(s). ; The equipment of the Ural Center for Shared Use "Modern Nanotechnology" UrFU was used. This work has been supported in part by the Ministry of Science and Higher Education of the Russian Federation under Project No. 3.9534.2017/8.9, by the Government of the Russian Federation (Act 211, Agreement No. 02.180 A03.21.0006) and by RFBR (Grant No. 17-52-80116-BRICS_a). This work was supported by the NSFC projects (Grant No. 51761145024), Shaan Xi province Project (Nos. 2017 ktpt-21 and 2018TD-024), and the 111 Project under Grant No. B14040.