Growth and characterization of the magnetic topological insulator candidate Mn₂Sb₂Te₅

We report a new member of topological insulator (TI) family i.e. Mn₂Sb₂Te₅, which belongs to MnSb₂Te₄family and is a sister compound of Mn₂Bi₂Te₅. An antiferromagnetic layer of (MnTe)₂has been inserted between quintuple layers of Sb₂Te₃. The crystal structure and chemical composition of as grown Mn₂Sb₂Te₅crystal 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 Mn₂Sb₂Te₅are elucidated through Raman spectroscopy. Temperature-dependent resistivityρ(T) of Mn₂Sb₂Te₅resulted in metallic behavior of the same with an up-turn at below around 20 K. Further, the magneto-transportρ(T) vsHof 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 Mn₂Sb₂Te₅clearly exhibited the characteristics of a magnetic TI.