Bulk textured MgB_2 material of nearly full density showing a weak c-axis alignment of the hexagonal MgB_2 grains parallel to the pressure direction was obtained by hot deformation of a stoichiometric MgB_2 pellet prepared by a gas-solid reaction. The texture of the material was verified by comparing the x-ray diffraction patterns of the hot deformed material with isotropic MgB_2 powder. A small, but distinct anisotropy of the upper critical field up to Hc2^{a,b}/Hc2^{c}~1.2 depending on degree of texture was found by resistance and susceptibility measurements. No anisotropy of the critical current density determined from magnetization measurements was found for the textured material.
@article{arxiv.cond-mat/0103408,
title = {Fully dense MgB_2 superconductor textured by hot deformation},
author = {A. Handstein and D. Hinz and G. Fuchs and K. -H. Müller and K. Nenkov and O. Gutfleisch and V. N. Narozhnyi and L. Schultz},
journal= {arXiv preprint arXiv:cond-mat/0103408},
year = {2007}
}
Comments
17 pages with 6 figures. Text modified, 2 figures added