Crystal Growth and basic transport and magnetic properties of MnBi2Te4

TL;DR

This study successfully synthesized MnBi2Te4 crystals, characterized their structural, transport, and magnetic properties, and identified features suggesting potential for quantum anomalous Hall effects.

Contribution

First detailed growth and comprehensive property analysis of MnBi2Te4 as a magnetic topological insulator.

Findings

Crystals mainly MnBi2Te4 with minor phases

Transport shows magnetic transition at 25K

Magnetoresistance exhibits negative and positive regimes

Abstract

We report successful growth of magnetic topological insulator (MTI) MnBi2Te4. The heating schedule basically deals with growth of the crystal from melt at 900C and very slow cooling (1C/hr) to around 600C with 24 hours hold time, followed by cooling to room temperature. Our detailed, PXRD Reitveld analysis showed that the resultant crystal is dominated mainly by MnBi2Te4 and minor phases of Bi2Te3 and MnTe. The transport measurements showed a step like behavior at around 150K followed by cusp like structure in resistivity at around 25K (TP) due reported anti-ferromagnetic ordering of Mn. Both the resistivity transitions are seen clearly in dR/dT measurements at 150K and 20K respectively. The 25K transition of the compound is also seen in magnetic susceptibility. Low temperature (5K) magnetoresistance (MR) in applied field of up to 6 Tesla exhibited negative ve MR below 3 Tesla and +ve for higher fields. Also, seen are steps in MR below one Tesla. The studied MnBi2Te4 MTI crystal could be a possible candidate for Quantum Anomalous Hall (QAH) effect.