Abstract:
An oxyborate Co2AlBO5 belonging to the ludwigite family is investigated using structural, thermodynamic, dielectric, and magnetic measurements. Magnetic measurements indicate that this system is seen to exhibit long-range magnetic ordering at TN=42K, signatures of which are also seen in the specific heat, dielectric susceptibility, and lattice parameters. The absence of a structural phase transition down to the lowest measured temperatures distinguishes it from the more extensively investigated Fe-based ludwigites. At low temperatures, the system is seen to stabilize in a reentrant superspin glass phase at TG=10.6K from within the magnetically ordered state. This ground state is also characterized by magnetic-field-induced metamagnetic transitions, which at the lowest measured temperatures exhibit a number of sharp magnetization steps, reminiscent of that observed in the mixed valent manganites.