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We report a new member of topological insulator (TI) family i.e. Mn 2 Sb 2 Te 5 , which belongs to MnSb 2 Te 4 family and is a sister compound of Mn 2 Bi 2 Te 5 . An antiferromagnetic layer of (MnTe) 2 has been inserted between quintuple layers of Sb 2 Te 3 . The crystal structure and chemical composition of as grown Mn 2 Sb 2 Te 5 crystal is experimentally visualized by single crystal x-ray diffractometer and field emission scanning electron microscopy. The valence states of individual constituents i.e., Mn, Sb and Te are ascertained through x-ray photo electron spectroscopy. Different vibrational modes of Mn 2 Sb 2 Te 5 are elucidated through Raman spectroscopy. Temperature-dependent resistivity ρ ( T ) of Mn 2 Sb 2 Te 5 resulted in metallic behavior of the same with an up-turn at below around 20 K. Further, the magneto-transport ρ ( T ) vs H of the same exhibited negative magneto-resistance (MR) at low temperatures below 20 K and small positive at higher temperatures. The low Temperature -ve MR starts decreasing at higher fields. The magnetic moment as a function of temperature at 100 Oe and 1 kOe showed anti-ferromagnetism (AFM) like down turn cusps at around 20 K and 10 K. The isothermal magnetization showed AFM like loops with some embedded ferromagnetic/paramagnetic (PM) domains at 5 K and purely PM like at 100 K. The studied Mn 2 Sb 2 Te 5 clearly exhibited the characteristics of a magnetic TI., (© 2023 IOP Publishing Ltd.)

Materials exhibiting bulk superconductivity along with magnetoresistance (MR) in their normal state have emerged as suitable candidates for topological superconductivity. In this article, we report a flux free method to synthesize single crystal of topological superconductor candidate Sn 4 Au. The phase purity and single crystalline nature are confirmed through various characterizations viz. x-ray diffraction, field emission scanning electron microscopy, selected area electron diffraction, and transmission electron microscopy. Chemical states of the constituent element viz. Sn and Au are analysed through x-ray photoelectron spectroscopy. Superconductivity in synthesized Sn 4 Au single crystal is evident form ρ-T plot, for which the critical field ( H c ) is determined through ρ-H plot at 2 K i.e. just below critical temperature T c . A positive MR is observed in ρ-H measurements at different temperatures above T c , viz. at 3 K, 5 K, 10 K and 20 K. Further, the magnetoconductivity (MC) is analysed by using Hikami-Larkin-Nagaoka formalism, which signifies the presence of weak antilocalization (WAL) effect in Sn 4 Au. Angle dependent magneto-transport measurement has been performed to detect the origin of observed WAL effect in Sn 4 Au single crystal. Normalized MC vs H cos θ plot shows presence of topological surface states in the studied system. It is evident that Sn 4 Au is a 2.6 K topological superconductor., (© 2022 IOP Publishing Ltd.)

The interplay between charges and spins may influence the dynamics of the carriers and determine their thermoelectric properties. In that respect, magneto-thermoelectric power MTEP, i.e. the measurements of the Seebeck coefficient S under the application of an external magnetic field, is a powerful technique to reveal the role of magnetic moments on S . This is illustrated by different transition metal chalcogenides: CuCrTiS 4 and CuMnTiS 4 magnetic thiospinels, which are compared with magnetic oxides, Curie-Weiss (CW) paramagnetic misfit cobaltites, ruthenates, either ferromagnetic perovskite or Pauli paramagnet quadruple perovskites, and CuGa 1- x Mn x Te 2 chalcopyrite telluride and Bi 1.99 Cr 0.01 Te 3 in which diluted magnetism is induced by 3%-Mn and 1%-Cr substitution, respectively. In the case of a ferromagnet (below T C ) and CW paramagnetic materials, the increase of magnetization at low T when a magnetic field is applied is accompanied by a decrease of the entropy of the carriers and hence S decreases. This is consistent with the lack of MTEP in the Pauli paramagnetic quadruple perovskites. Also, no significant MTEP is observed in CuGa 1- x Mn x Te 2 and Bi 1.99 Cr 0.01 Te 3 , for which Kondo-type interaction between magnetic moments and carriers prevails. In contrast, spin glass CuCrTiS 4 exhibits negative MTEP like in ferromagnetic ruthenates and paramagnetic misfit cobaltites. This investigation of some chalcogenides and oxides provides key ingredients to select magnetic materials for which S benefits from spin entropy., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2021 The Author(s). Published by National Institute for Materials Science in partnership with Taylor & Francis Group.)

In this work, we developed and fabricated a paper-based anisotropic magneto-resistive sensor using a sputtered permalloy (Ni 81 Fe 19 ) thin film. To interpret the characteristics of the sensor, we proposed a computational model to capture the influence of the stochastic fiber network of the paper surface and to explain the physics behind the empirically observed difference in paper-based anisotropic magneto-resistance (AMR). Using the model, we verified two main empirical observations: (1) The stochastic fiber network of the paper substrate induces a shift of 45 ∘ in the AMR response of the paper-based Ni 81 Fe 19 thin film compared to a Ni 81 Fe 19 film on a smooth surface as long as the fibrous topography has not become buried. (2) The ratio of magnitudes of AMR peaks at different anisotropy angles and the inverted AMR peak at the 90 ∘ -anisotropy angle are explained through the superposition of the responses of Ni 81 Fe 19 inheriting the fibrous topography and smoother Ni 81 Fe 19 on buried fibrous topographies. As for the sensitivity and reproducibility of the sensor signal, we obtained a maximum AMR peak of 0 . 4 % , min-max sensitivity range of [ 0 . 17 , 0 . 26 ] % , average asymmetry of peak location of 2 . 7 kA m within two consecutive magnetic loading cycles, and a deviation of 250⁻850 A m of peak location across several anisotropy angles at a base resistance of ∼100 Ω . Last, we demonstrated the usability of the sensor in two educational application examples: a textbook clicker and interactive braille flashcards.

Magnetoresistance (MR), the change of a material's electrical resistance in response to an applied magnetic field, is a technologically important property that has been the topic of intense study for more than a quarter century. We report the observation of an unusual "butterfly"-shaped titanic angular magnetoresistance (AMR) in the nonmagnetic Dirac material, ZrSiS, which we find to be the most conducting sulfide known, with a 2-K resistivity as low as 48(4) nΩ⋅cm. The MR in ZrSiS is large and positive, reaching nearly 1.8 × 10 5 percent at 9 T and 2 K at a 45° angle between the applied current ( I || a ) and the applied field (90° is H || c ). Approaching 90°, a "dip" is seen in the AMR, which, by analyzing Shubnikov de Haas oscillations at different angles, we find to coincide with a very sharp topological phase transition unlike any seen in other known Dirac/Weyl materials. We find that ZrSiS has a combination of two-dimensional (2D) and 3D Dirac pockets comprising its Fermi surface and that the combination of high-mobility carriers and multiple pockets in ZrSiS allows for large property changes to occur as a function of angle between applied fields. This makes it a promising platform to study the physics stemming from the coexistence of 2D and 3D Dirac electrons as well as opens the door to creating devices focused on switching between different parts of the Fermi surface and different topological states.

Organic multiferroic tunnel junctions based on La 0.6 Sr 0.4 MnO 3 /poly(vinylidene fluoride) (PVDF)/Co structures are fabricated. The tunneling magneto-resistance sign can be changed by electrically switching the ferroelectric polarization of PVDF barrier. It is demonstrated that the spin-polarization of the PVDF/Co spinterface can be actively controlled by tuning the ferroelectric polarization of PVDF. This study opens new functionality in controlling the injection of spin polarization into organic materials via the ferroelectric polarization of the barrier., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)