Microstructure and pinning properties of hexagonal-disc shaped single crystalline MgB2

TL;DR

This study reports the synthesis and microstructural analysis of hexagonal-disc MgB2 single crystals, revealing their symmetry, crystallography, and weak pinning properties, making them ideal for studying directional physical properties.

Contribution

The paper presents a method to synthesize well-shaped MgB2 single crystals and thoroughly analyzes their microstructure and pinning properties, highlighting their suitability for directional studies.

Findings

Crystals exhibit MgB2 symmetry with precise crystallographic orientation.

Crystals show weak pinning and wide reversible magnetic regions.

Well-shaped crystals are ideal for studying directional physical properties.

Abstract

We synthesized hexagonal-disc-shaped MgB2 single crystals under high-pressure conditions and analyzed the microstructure and pinning properties. The lattice constants and the Laue pattern of the crystals from X-ray micro-diffraction showed the crystal symmetry of MgB2. A thorough crystallographic mapping within a single crystal showed that the edge and c-axis of hexagonal-disc shape exactly matched the (10-10) and the (0001) directions of the MgB2 phase. Thus, these well-shaped single crystals may be the best candidates for studying the direction dependences of the physical properties. The magnetization curve and the magnetic hysteresis for these single crystals showed the existence of a wide reversible region and weak pinning properties, which supported our single crystals being very clean.