Synthesis and Characterization of Oxide Chloride Sr2VO3Cl, a Layered S = 1 Compound

The mixed-anion compound with composition Sr2VO3Cl has been synthesized for the first time, using the conventional high-temperature solid-state synthesis technique in a closed silica ampule under inert conditions. This compound belongs to the known Sr2TmO3Cl (Tm = Sc, Mn, Fe, Co, Ni) family, but with Tm = V. All homologues within this family can be described with the tetragonal space group P4/nmm (No. 129); from a Rietveld refinement of powder X-ray diffraction data on the Tm = V homologue, the unit cell parameters were determined to a = 3.95974(8) and c = 14.0660(4) Å, and the atomic parameters in the crystal structure could be estimated. The synthesized powder is black, implying that the compound is a semiconductor. The magnetic investigations suggest that Sr2VO3Cl is a paramagnet at high temperatures, exhibiting a μeff = 2.0 μB V-1 and antiferromagnetic (AFM) interactions between the magnetic vanadium spins (θCW = −50 K), in line with the V-O-V advantageous super-exchange paths in the V-O layers. Specific heat capacity studies indicate two small anomalies around 5 and 35 K, which however are not associated with long-range magnetic ordering. 35Cl ss-NMR investigations suggest a slow spin freezing below 4.2 K resulting in a glassy-like spin ground state

Anomalous Hall effect and magnetoresistance in micro-ribbons of the magnetic Weyl semimetal candidate PrRhC2

PrRhC2 belongs to the rare-earth carbides family whose properties are of special interest among topological semimetals due to the simultaneous breaking of both inversion and time-reversal symmetry. The concomitant absence of both symmetries grants the possibility to tune the Weyl nodes chirality and to enhance topological effects like the chiral anomaly. In this work, we report on the synthesis and compare the magnetotransport measurements of a poly- and single crystalline PrRhC2 sample. Using a remarkable and sophisticated technique, the PrRhC2 single crystal is prepared via focused ion beam cutting from the polycrystalline material. Our magnetometric and specific heat analyses reveal a non-collinear antiferromagnetic state below 20K, as well as short-range magnetic correlations and/or magnetic fluctuations well above the onset of the magnetic transition. The transport measurements on the PrRhC2 single crystal display an electrical resistivity peak at 3K and an anomalous Hall effect below 6K indicative of a net magnetization component in the ordered state. Furthermore, we study the angular variation of magnetoresistivities as a function of the angle between the in-plane magnetic field and the injected electrical current. We find that both the transverse and the longitudinal resistivities exhibit fourfold angular dependencies due to higher-order terms in the resistivity tensor, consistent with the orthorhombic crystal symmetry of PrRhC2. Our experimental results may be interpreted as features of topological Weyl semimetallic behavior in the magnetotransport properties

Intermixing-Driven Surface and Bulk Ferromagnetism in the Quantum Anomalous Hall Candidate MnBi6Te10

The recent realizations of the quantum anomalous Hall effect (QAHE) in MnBi2Te4 and MnBi4Te7 benchmark the (MnBi2Te4)(Bi2Te3)n family as a promising hotbed for further QAHE improvements. The family owes its potential to its ferromagnetically (FM) ordered MnBi2Te4 septuple layers (SLs). However, the QAHE realization is complicated in MnBi2Te4 and MnBi4Te7 due to the substantial antiferromagnetic (AFM) coupling between the SLs. An FM state, advantageous for the QAHE, can be stabilized by interlacing the SLs with an increasing number n of Bi2Te3 quintuple layers (QLs). However, the mechanisms driving the FM state and the number of necessary QLs are not understood, and the surface magnetism remains obscure. Here, robust FM properties in MnBi6Te10 (n = 2) with Tc ≈ 12 K are demonstrated and their origin is established in the Mn/Bi intermixing phenomenon by a combined experimental and theoretical study. The measurements reveal a magnetically intact surface with a large magnetic moment, and with FM properties similar to the bulk. This investigation thus consolidates the MnBi6Te10 system as perspective for the QAHE at elevated temperatures

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

PrRhC2 belongs to the rare-earth carbides family, whose properties are of special interest among topological semimetals due to the simultaneous breaking of both inversion and time-reversal symmetry. The concomitant absence of both symmetries grants the possibility to tune the Weyl nodes chirality and to enhance topological effects such as the chiral anomaly. In this paper, we report on the synthesis and compare the magnetotransport measurements of polycrystalline PrRhC2 samples and a single-crystalline PrRhC2 sample. Using a remarkable and sophisticated technique, the PrRhC2 single crystal is prepared via focused-ion-beam cutting from the polycrystalline material. Our magnetometric and specific heat analyses reveal a noncollinear antiferromagnetic state below 20K, as well as short-range magnetic correlations and/or magnetic fluctuations well above the onset of the magnetic transition. The transport measurements on the PrRhC2 single crystal display an electrical resistivity peak at 3K and an anomalous Hall effect below 6K indicative of a net magnetization component in the ordered state. Furthermore, we study the angular variation of magnetoresistivities as a function of the angle between the in-plane magnetic field and the injected electrical current. We find that both the transverse and the longitudinal resistivities exhibit fourfold angular dependencies due to higher-order terms in the resistivity tensor, consistent with the orthorhombic crystal symmetry of PrRhC2. Our experimental results may be interpreted as features of topological Weyl semimetallic behavior in the magnetotransport properties.Peer reviewe

Heavy-atom antiferromagnet gdbite: an interplay of magnetism and topology in a symmetry-protected topological semimetal

Magnetic topological semimetals (MTSs) are quantum materials highly desirable for spintronics. We report the synthesis, the crystal structure, the chemical bonding analysis, the magneto(transport) properties, and the bulk and surface electronic structures of GdBiTe. It is a high-Z isostructural analogue of the archetypical nodal-line TS ZrSiS and a recently discovered MTS LnSbTe (Ln = Ce, Gd). GdBiTe crystallizes in the nonsymmorphic space group P4/nmm (No. 129) with a = 4.3706(2) Å and c = 9.2475(7) Å. Chemical bonding analysis describes it as a layered structure of alternating weakly bonded double-stacked covalent [GdTe] layers and planar square [Bi] nets. GdBiTe exhibits an antiferromagnetic transition at TN = 15 K, and an additional transition, possibly a spin reorientation into a canted antiferromagnetic state, occurs below ca. 5 K. The electrical resistivity is compatible with a semimetallic behavior above TN

Intermixing-Driven Surface and Bulk Ferromagnetism in the Quantum Anomalous Hall Candidate MnBi6Te10

The recent realizations of the quantum anomalous Hall effect (QAHE) in MnBi2Te4 and MnBi4Te7 benchmark the (MnBi2Te4)(Bi2Te3)n family as a promising hotbed for further QAHE improvements. The family owes its potential to its ferromagnetically (FM) ordered MnBi2Te4 septuple layers (SLs). However, the QAHE realization is complicated in MnBi2Te4 and MnBi4Te7 due to the substantial antiferromagnetic (AFM) coupling between the SLs. An FM state, advantageous for the QAHE, can be stabilized by interlacing the SLs with an increasing number n of Bi2Te3 quintuple layers (QLs). However, the mechanisms driving the FM state and the number of necessary QLs are not understood, and the surface magnetism remains obscure. Here, robust FM properties in MnBi6Te10 (n = 2) with Tc ≈ 12 K are demonstrated and their origin is established in the Mn/Bi intermixing phenomenon by a combined experimental and theoretical study. The measurements reveal a magnetically intact surface with a large magnetic moment, and with FM properties similar to the bulk. This investigation thus consolidates the MnBi6Te10 system as perspective for the QAHE at elevated temperatures.Fil: Tcakaev, Abdul Vakhab. Universität Würzburg; Alemania. Würzburg-dresden Cluster Of Excellence Ct.qmat; AlemaniaFil: Rubrecht, Bastian. Leibniz-institut Für Festkörper- Und Werkstoffforschung Dresden; AlemaniaFil: Facio, Jorge Ismael. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche | Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Leibniz-institut Für Festkörper- Und Werkstoffforschung Dresden; AlemaniaFil: Zabolotnyy, Volodymyr B.. Würzburg-dresden Cluster Of Excellence Ct.qmat; Alemania. Universität Würzburg; AlemaniaFil: Corredor, Laura T.. Leibniz-institut Für Festkörper- Und Werkstoffforschung Dresden; AlemaniaFil: Folkers, Laura C.. Würzburg-dresden Cluster Of Excellence Ct.qmat; Alemania. Technische Universität Dresden; AlemaniaFil: Kochetkova, Ekaterina. Leibniz-institut Für Festkörper- Und Werkstoffforschung Dresden; AlemaniaFil: Peixoto, Thiago R. F.. Universität Würzburg; Alemania. Würzburg-dresden Cluster Of Excellence Ct.qmat; AlemaniaFil: Kagerer, Philipp. Universität Würzburg; Alemania. Würzburg-dresden Cluster Of Excellence Ct.qmat; AlemaniaFil: Heinze, Simon. Institut Für Theoretische Physik Heidelberg; AlemaniaFil: Bentmann, Hendrik. Würzburg-dresden Cluster Of Excellence Ct.qmat; Alemania. Universität Würzburg; AlemaniaFil: Green, Robert J.. University of Saskatchewan; Canadá. University of British Columbia; CanadáFil: Gargiani, Pierluigi. Alba Synchrotron Light Facility; EspañaFil: Valvidares, Manuel. Alba Synchrotron Light Facility; EspañaFil: Weschke, Eugen. Helmholtz-zentrum Berlin Für Materialien Und Energie; AlemaniaFil: Haverkort, Maurits W.. Institut Für Theoretische Physik Heidelberg; AlemaniaFil: Reinert, Friedrich. Würzburg-dresden Cluster Of Excellence Ct.qmat; Alemania. Universität Würzburg; AlemaniaFil: van den Brink, Jeroen. Würzburg-dresden Cluster Of Excellence Ct.qmat; Alemania. Leibniz-institut Für Festkörper- Und Werkstoffforschung Dresden; Alemania. Technische Universität Dresden; AlemaniaFil: Büchner, Bernd. Leibniz-institut Für Festkörper- Und Werkstoffforschung Dresden; Alemania. Würzburg-dresden Cluster Of Excellence Ct.qmat; Alemania. Technische Universität Dresden; AlemaniaFil: Wolter, Anja U. B.. Würzburg-dresden Cluster Of Excellence Ct.qmat; Alemania. Leibniz-institut Für Festkörper- Und Werkstoffforschung Dresden; AlemaniaFil: Isaeva, Anna. Leibniz-institut Für Festkörper- Und Werkstoffforschung Dresden; Alemania. University of Amsterdam; Países BajosFil: Hinkov, Vladimir. Universität Würzburg; Alemania. Würzburg-dresden Cluster Of Excellence Ct.qmat; Alemani