On the growth and characterization of SmOFe_1−𝑥Co_𝑥As single crystals

F. Anger, M.-I. Sturza, R. Firouzmandi, V. Kocsis, A. U.B. Wolter-Giraud, B. Büchner, S. Wurmehl

J. Cryst. Growth 627, 127473 (2024)

 https://doi.org/10.1016/j.jcrysgro.2023.127473

We report the crystal growth of SmOFe_1−𝑥Co_𝑥As single crystals with Co content 0 ≤ 𝑥 ≤ 0.25 via the solid-state single crystal growth method at ambient pressure. We discuss in detail which are the optimal parameters for the growth of SmOFe_1−𝑥Co_𝑥As single crystals and rationalize the mechanisms to activate the diffusion-driven solid-state single crystal growth in the system under study. As expected across the series, charge doping suppresses the structural and magnetic transitions until for 5% Co content superconductivity is established. In particular, the splitting and clear differentiation of the structural and subsequent magnetic transition is rarely seen for 𝑅𝐸OFeAs compounds, but well resolved for the Fe-rich SmOFe_1−𝑥Co_𝑥As single crystals and even for the 𝑥 = 0.0125 crystal, but smeared out for the corresponding polycrystalline samples. Hence, the SmOFe_1−𝑥Co_𝑥As single crystal presented in this work are of exceptional high quality.

Phase transformation in Mn₃Ga considering different degrees of deformation

Gloria Kirste, Jens Freudenberger, Sabine Wurmehl

Acta Materialia 258, 119205 (2023)

https://doi.org/10.1016/j.actamat.2023.119205

Anomalous Hall effect and magnetoresistance in microribbons of the magnetic Weyl semimetal candidate PrRhC₂

Mickey Martini, Helena Reichlova, Laura T. Corredor, Dominik Kriegner, Yejin Lee, Luca Tomarchio, Kornelius Nielsch, Ali G. Moghaddam, Jeroen van den Brink, Bernd Büchner, Sabine Wurmehl, Vitaliy Romaka, and Andy Thomas

Phys. Rev. Materials 7, 104205 (2023)

https://doi.org/10.1103/PhysRevMaterials.7.104205

Flux Growth and Characterization of Bulk InVO₄ Crystals

O. Voloshyna, M. V Gorbunov, D. Mikhailova, A. Maljuk, S. Seiro, B. Büchner

Crystals 13, 1439 (2023)

https://doi.org/10.3390/cryst13101439

The flux growth of InVO₄ bulk single crystals has been explored for the first time. Crystals of InVO₄ of typical size 0.5 × 1 × 7 mm³ were obtained using copper pyrovanadate (Cu₂V₂O₇) as a flux, using Pt crucibles.  X-ray absorption spectroscopy showed that oxidation states of indium and vanadium ions are +3 and +5, respectively. The size and high quality of the obtained InVO₄ crystals makes them excellent candidates for further study of their physical properties.

Magnetic structure of the swedenborgite compound CaBaMn₂⁢Fe₂⁢O₇ derived by powder neutron diffraction and Mössbauer spectroscopy

N. Qureshi, R. Morrow, M. Valldor, I. Puente-Orench, P. Adler

Phys. Rev. B 106, 144428 (2022)

https://doi.org/10.1103/PhysRevB.106.144428

A combination of neutron diffraction and ⁵⁷Fe Mössbauer spectroscopy on a powder sample of swedenborgite CaBaMn₂⁢Fe2⁢O₇ shows that the undistorted hexagonal crystal structure (space group 𝑃⁢63⁢𝑚⁢𝑐) is preserved down to low temperatures, and undergoes transition into a magnetically long-range ordered phase at 𝑇_N = 205 K. The magnetic Bragg peak intensities from the powder diffraction patterns along with a symmetry analysis of the employed models unambiguously reveal the classical √3×√3 magnetic structure on a hexagonal lattice with propagation vector 𝐪=(13130). The nuclear Bragg peak intensities confirmed statistical distribution of Fe and Mn ions on both trigonal and kagome sites of the complex swedenborgite structure.