Gd3Fe5O12 garnet ceramic with mesoscale structuring processed by slip casting. Effect of magnetic field

Abstract

This study reports the fabrication of Gd₃Fe₅O₁₂ ferrimagnetic ceramic by magnetic slip casting under applied magnetic fields of 1T and 12T, followed by solid-state sintering. Structural, microstructural, and magnetic properties were investigated using X-ray diffraction, scanning and transmission electron microscopy, Mössbauer spectroscopy, and magnetometry. XRD and SAED confirmed the presence of single-phase cubic garnet in the dense bulk ceramic with no detectable crystallographic texture. Rietveld analysis revealed relatively large crystallite sizes in the range of 165-350 nm. SEM observations showed that magnetic fields during magnetic slip casting, especially of high value (12T), promote the organization of local mesoscale grain assemblies with a preferential spatial arrangement, forming two-dimensional magnetically correlated regions. Magnetic measurements indicate that this mesoscale structure significantly affects the low-field magnetic behavior, as evidenced by pronounced ZFC-FC irreversibility and anisotropic magnetic response. Despite distinct magnetic relaxation patterns caused by microstructural differences, all magnetic slip-casted samples exhibit the same elevated compensation temperature (θ_C = 336 K), which is primarily attributed to the large crystallite sizes achieved through the processing route. Comparison with the 0T slip-casted reference sample indicates that the enhanced compensation behaviour is primarily associated with the processing-induced local structural/microstructural state rather than directly with the applied magnetic field. These findings demonstrate that magnetic slip casting is a practical method for engineering magnetic properties in rare-earth iron garnet ceramics by designing their microstructure at the mesoscale.