New superconductor of the M$_{2}$AX family with Ti$_{2}$GeC composition.

In this work the Ti$_{2}$GeC phase is investigated by x-ray diffraction, magnetic and resistivity measurements. Polycrystalline samples with nominal compositions Ti$_{2}$GeC were prepared by solid state reaction. The samples were encapsulated under argon and heat-treated at 1100\r{ }C for 240 hours. X-ray powder diffractograms suggest that all peaks can be indexed with the hexagonal phase of Cr$_{2}$AlC prototype. The electrical resistance as a function of temperature for the Ti$_{2}$GeC reveals a standard metal like behavior when this material is cooled from the heat treatment under equilibrium conditions. However, magnetic measurements display diamagnetic behavior close to 9.5K. On the other hand, when the Ti$_{2}$GeC phase is submitted a rapid quenching the R(T,B) curve shows superconducting critical temperature close to 9.5K without applied magnetic field. The magnetoresistance data with applied magnetic filed suggests bulk superconductivity. In spite of the great number of compounds which belong to this family, superconductivity has been reported for five cases. So, this work sustains the idea of the existence of a new class of superconducting materials that crystallizes in the Cr$_{2}$AlC prototype.