High magnetic field study of the Gd-Co exchange interactions in GdCo₁₂B₆

Pulsed magnetic fields up to 68 Tesla have been used to determine the intersublattice coupling strength and its temperature dependence of GdCo₁₂B₆ compound. This compound exhibits ferrimagnetic behaviour below 163 ± 2 K. Two antiferromagnetically coupled sublattices cancel out at compensation temperature at about 48 K. They are carrying magnetization of typically 0.42 μ_B/Co atom and 7 μ_B/Gd. The intrinsic magnetic properties of the GdCo₁₂B₆ compound have been determined by combining low temperature magnetic measurements in both steady and pulsed magnetic field, as well as isofield studies in steady field. At 4.2 K, the magnetization curve of GdCo₁₂B₆ is found to reach the full saturation with sum of both sublattice magnetizations for an applied magnetic field of about 68 T. In addition a detailed study is presented in the whole ordered temperature range on the basis of magnetization curves recorded using pulsed magnetic field up to 60 T. This has enabled to investigate the intersublattice coupling strength and its temperature dependence, a value J_Co-Gd/k_B = −5.3 ± 0.3 K is derived from the magnetization curves whereas one gets much larger value for J_Co-Co/k_B = 108 K.