  In 2007, type-I superconductivity in heavily boron-doped silicon carbide was
discovered. The question arose, if it is possible to achieve a superconducting
phase by introducing dopants different from boron. Recently, aluminum-doped
silicon carbide was successfully found to superconduct by means of resistivity
and DC magnetization measurements. In contrast to boron-doped silicon carbide,
the aluminum doped system is treated as a type-II superconductor because of the
absence of an hysteresis in data measured upon decreasing and increasing
temperature in finite magnetic fields. In this paper, results of a recent AC
susceptibility study on aluminum-doped silicon carbide are presented. In higher
applied DC magnetic fields and at low temperatures, a weak indication of
supercooling with a width of a few mK is found. This supports the conclusion
that aluminum-doped silicon carbide is located near to the border between
type-I and type-II superconductivity, as pointed out in a recent theoretical
work, too.
