Disordered magnetism in the homologue series YBaCo4-xZnxO7 (x = 0, 1, 2, 3)

The magnetic properties of four compounds in the series YBaCo4-xZnxO7 (x = 0, 1, 2, 3) were investigated. For all compositions magnetic transitions were observed (Tf) over the temperature range 66-3 K observed with ac susceptibility and dc magnetometry. Furthermore, all ac measurements proved to be frequency-dependent: Tf increases with an increase in frequency. The real part of the magnetic susceptibility (χ') was, in all four cases, accompanied by an energy loss in the magnetic coupling, indicated as contributions to the imaginary part (χ'). The maximum χ' appeared just below the maximum χ'. Using the Arrhenius law, the Vogel-Fulcher law and the power law, it was possible to conclude that the compounds should be defined as spin-glass-like materials. The dc magnetizations clearly show differences between field-cooled and zero-field-cooled measurements. None of the compounds exhibited any metamagnetic property and, using a new data analysis method, a possible saturation field could be calculated for YBaCo4O7. Relaxation measurements on YBaCo3ZnO7 indicate that the system has no ageing effects. The magnetic properties can be described as having two connected magnetic substructures represented as dimensionalities: axial (1D) and in-plane (2D). This was concluded by comparing the magnetic properties with structural details