High-field magnetization and specific heat of UCu2T3Al7 alloys where T = Cr, Mn and Fe(II)

The UCu2T3Al7 alloys, where T = Cr, Mn and Fe, crystallize in the ThMn12-type tetragonal structure. Earlier investigation of magnetic and electrical properties revealed their complex magnetic behavior except of the Cr compound, which is paramagnetic, whereas their electrical resistivity is weakly temperature dependent. At present we report on the magnetization measurements at 4.2 and 77 K in the steady magnetic field up to 14 T and in the pulsed field up to 34 T with a pulse duration of 10 ms at T = 4.2 K. These experiments confirmed paramagnetism of the Cr alloy and showed lack of saturation for the compounds of the Mn and Fe with the 'saturation' magnetic moment amounting to 3.1 and 5.0 μB/f.u., respectively. In turn, the specific heat was measured in the temperature range 1.2-70 K in magnetic field μ0H = 0 and 7 K using a home-made and fully automatic calorimeter. The investigation of the specific heat at temperature 2-300 K has been done using Quantum Design PPMS machine. The magnetic field does not in principle influence the obtained results, whereas the coefficient of the electronic specific heat, γ is strongly enhanced and amounts to 410, 330 and 150 mJ mol-1 K-2 for the Cr, Mn and Fe compounds, respectively