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We report the characterization of (GaSc)2-xFexO3. The composition range where the multinary metal oxide is stable, as well as nonlinear trends in the lattice parameters are described. Select compositions of GaSc1-yFeyO3 are included to compare trends. Fe shows an enhanced solubility when replacing Sc rather than Ga. Field- and temperature-dependent magnetic data are included, and linear trends in the magnetic frustration are discussed alongside a brief comparison to the magnetic properties of GaSc1-yFeyO3. The field-dependent properties, as well as anomalies in the hysteresis loops and relaxation of the remnant magnetization are discussed, as well as indications that long-range order may be present in dilute Fe samples. [ABSTRACT FROM AUTHOR]

Symmetry and topology are central to understanding quantum Hall ferromagnets (QHFMs), two-dimensional electronic phases with spontaneously broken spin or pseudospin symmetry whose wavefunctions also have topological properties.sup.1,2. Domain walls between distinct broken-symmetry QHFM phases are predicted to host gapless one-dimensional modes--that is, quantum channels that emerge because of a topological change in the underlying electronic wavefunctions at such interfaces. Although various QHFMs have been identified in different materials.sup.3-8, interacting electronic modes at these domain walls have not been probed. Here we use a scanning tunnelling microscope to directly visualize the spontaneous formation of boundary modes at domain walls between QHFM phases with different valley polarization (that is, the occupation of equal-energy but quantum mechanically distinct valleys in the electronic structure) on the surface of bismuth. Spectroscopy shows that these modes occur within a topological energy gap, which closes and reopens as the valley polarization switches across the domain wall. By changing the valley flavour and the number of modes at the domain wall, we can realize different regimes in which the valley-polarized channels are either metallic or develop a spectroscopic gap. This behaviour is a consequence of Coulomb interactions constrained by the valley flavour, which determines whether electrons in the topological modes can backscatter, making these channels a unique class of interacting one-dimensional quantum wires. QHFM domain walls can be realized in different classes of two-dimensional materials, providing the opportunity to explore a rich phase space of interactions in these quantum wires. Scanning tunnelling microscopy shows that 1D channels between quantum Hall states with different valley polarization are metallic or insulating depending on constraints imposed on electron-electron interaction by valley flavour., Author(s): Mallika T. Randeria [sup.1] , Kartiek Agarwal [sup.2] , Benjamin E. Feldman [sup.1] [sup.5] [sup.6] , Hao Ding [sup.1] , Huiwen Ji [sup.3] , R. J. Cava [sup.3] , [...]

Magnetic toroidicity is an uncommon type of magnetic structure in solid-state materials. Here, we experimentally demonstrate that collinear spins in a material with R-3 lattice symmetry can host a significant magnetic toroidicity, even parallel to the ordered spins. Taking advantage of a single crystal sample of CoTe6O13 with an R-3 space group and a Co2+ triangular sublattice, temperature-dependent magnetic, thermodynamic, and neutron diffraction results reveal A-type antiferromagnetic order below 19.5 K, with magnetic point group -3′ and k = (0,0,0). Our symmetry analysis suggests that the missing mirror symmetry in the lattice could lead to the local spin canting for a toroidal moment along the c axis. Experimentally, we observe a large off-diagonal magnetoelectric coefficient of 41.2 ps/m that evidences the magnetic toroidicity. In addition, the paramagnetic state exhibits a large effective moment per Co2+, indicating that the magnetic moment in CoTe6O13 has a significant orbital contribution. CoTe6O13 embodies an excellent opportunity for the study of next-generation functional magnetoelectric materials.Magnetoelectric coupling, where magnetic and electronic order is linked, allows for the control of magnetism via an electric field and vice versa, potentially offering new approaches to data storage, sensors, actuators and wealth of other devices. Here, using a diverse array of experimental probes, Xu et al show the emergence of both diagonal and off-diagonal magnetoelectric coupling in CoTe6O13. [ABSTRACT FROM AUTHOR]

Breaking down barriers Topological states have become the subject of much attention from condensed-matter physicists, as evidence accumulates to show that these states can be found on the surface of certain materials -- in particular, bulk compounds called topological insulators. As a product of their topological nature, topological surface states are predicted to have the remarkable property of being robust against imperfections. This can allow, for example, the conduction of electronic currents without dissipation. Ali Yazdani and his team now report a tantalizing finding from scanning tunnelling microscope measurements -- that topological surface states on antimony can be transmitted with high probability through naturally occurring barriers that stop other conventional surface states of common metals. The authors suggest that their findings indicate that topological surface states could be exploited in novel applications of nanoscale electronic devices. Topological surface states are a class of electronic states that might be of interest in quantum computing or spintronic applications. They are predicted to be robust against imperfections, but so far there has been no evidence that these states do transmit through naturally occurring surface defects. Here, scanning tunnelling microscopy has been used to show that topological surface states of antimony can be transmitted through naturally occurring barriers that block non-topological surface states of common metals. Topological surface states are a class of novel electronic states that are of potential interest in quantum computing or spintronic applications.sup.1,2,3,4,5,6,7. Unlike conventional two-dimensional electron states, these surface states are expected to be immune to localization and to overcome barriers caused by material imperfection.sup.8,9,10,11,12,13,14. Previous experiments have demonstrated that topological surface states do not backscatter between equal and opposite momentum states, owing to their chiral spin texture.sup.15,16,17,18. However, so far there is no evidence that these states in fact transmit through naturally occurring surface defects. Here we use a scanning tunnelling microscope to measure the transmission and reflection probabilities of topological surface states of antimony through naturally occurring crystalline steps separating atomic terraces. In contrast to non-topological surface states of common metals (copper, silver and gold).sup.19,20,21,22,23, which are either reflected or absorbed by atomic steps, we show that topological surface states of antimony penetrate such barriers with high probability. This demonstration of the extended nature of antimony's topological surface states suggests that such states may be useful for high current transmission even in the presence of atomic-scale irregularities--an electronic feature sought to efficiently interconnect nanoscale devices., Author(s): Jungpil Seo [sup.1] , Pedram Roushan [sup.1] , Haim Beidenkopf [sup.1] , Y. S. Hor [sup.2] , R. J. Cava [sup.2] , Ali Yazdani [sup.1] Author Affiliations: (1) Joseph [...]

Author(s): Cheng Gong [1]; Lin Li [2]; Zhenglu Li [3, 4]; Huiwen Ji [5]; Alex Stern [2]; Yang Xia [1]; Ting Cao [3, 4]; Wei Bao [1]; Chenzhe Wang [1]; [...]

Author(s): Yayu Wang [1]; Nyrissa S. Rogado [2]; R. J. Cava [2, 3]; N. P. Ong (corresponding author) [1, 3] In an electric field, the flow of electrons in a [...]