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Here, we report successful single crystal growth of new possible magnetic topological insulator (MTI) FeBi2Te4 by a self-flux method via a vacuum encapsulation process. The detailed Rietveld analysis of powder XRD data shows the as-grown MTI crystal to be mainly dominated by the FeBi2Te4 phase along with minority phases of Bi2Te3 and FeTe. Scanning electron microscope (SEM) image shows the morphology of as-grown MTI single crystal to be of layered type laminar structure. Raman spectroscopy of the crystal exhibited three distinct phonon modes at 65, 110, and 132 cm−1 along with two split secondary modes at 90, and 144 cm−1. The secondary split modes are the result of FeTe intercalation in the Bi2Te3 unit cell. Magnetoresistance (MR%) measurement has been performed at different temperatures, i.e., 200 K, 20 K, and 2 K in applied magnetic fields up to ± 12 Tesla, which showed very low MR in comparison with pure Bi2Te3 crystal. Temperature dependence of DC magnetization measurements shows the FeBi2Te4 crystal to be mainly of ferromagnetic (FM) or ferrimagnetic nature above 295 K, albeit a secondary weak magnetic transition is seen at 54–46 K as well. Detailed isothermal magnetization (MH) results showed that the FM saturation moment at 295 K is 0.00213 emu/g, which is nearly invariant until 400 K. In summary, we had grown an MTI FeBi2Te4 single crystal, which may be a possible entrant for the quantum anomalous Hall (QAH) effect at room temperature or above. [ABSTRACT FROM AUTHOR]

We study the structural and bulk superconducting properties of self-flux grown PdBi2Te3 single crystal. Phase purity of as grown crystal is confirmed by Rietveld refinement of gently crushed powder XRD of the same. PdBi2Te3 crystallizes in rhombohedral structure with R-3 m space group along with small impurity of Bi. Scanning electron microscopy (SEM) images showed layered structure and the elemental analysis by energy dispersive X-ray analysis (EDAX) done on same confirmed the stoichiometry to be near to PdBi2Te3. Characteristic vibrational modes, viz., A11g, Eg2, and A21g, are clearly observed in Raman spectrum and are slightly shifted from that as in case of Bi2Te3. Bulk superconductivity is confirmed by FC and ZFC magnetization measurements (M-T) exhibiting diamagnetic transition with Tconset at around 6 K. M-H plots at different temperatures of 2 K, 2.5 K, 3 K, 3.5 K, 4 K, 4.5 K, 5 K, and 6 K showed clear opening of the loop right up to 6 K. Both M-T and M-H clearly establish the appearance of bulk type II superconductivity below 6 K in studied PdBi2Te3. The lower critical field Hc1 and upper critical field Hc2 are at 180 Oe at 4800 Oe, respectively, at 2 K for as grown PdBi2Te3 crystal. Other critical parameters of superconductivity such as coherence length, penetration depth and kappa parameter are also calculated. [ABSTRACT FROM AUTHOR]