We report measurements of the transport and the magnetic properties of high-quality, sub-millimeter-sized MgB2 single crystals with clear hexagonal-plate shapes. The low-field magnetization and the magnetic hysteresis curves show the vortex pinning of these crystals to be very weak. The Debye temperature of ΘD∼1100 K, obtained from the zero-field resistance curve, suggests that the normal-state transport properties are dominated by electron-phonon interactions. The resistivity ratio between 40 K and 300 K was about 5, and the upper critical field anisotropy ratio was 3 ± 0.2 at temperatures around 32 K.
@article{arxiv.cond-mat/0105330,
title = {Superconducting properties of well-shaped MgB2 single crystal},
author = {Kijoon H. P. Kim and Jae-Hyuk Choi and C. U. Jung and P. Chowdhury and Min-Seok Park and Heon-Jung Kim and J. Y. Kim and Zhonglian Du and Eun-Mi Choi and Mun-Seog Kim and W. N. Kang and Sung-Ik Lee and Gun Yong Sung and Jeong Yong Lee},
journal= {arXiv preprint arXiv:cond-mat/0105330},
year = {2009}
}