Magnetic feature of the Z-type hexaferrite produced by the citrate and Pechini synthesis routes

Abstract

The Z-type Sr₃Co₂Fe₂₄O₄₁ hexaferrite constitutes a family of relatively new materials, which offers potential technological applications in the spintronics industry due to its magnetoelectric properties at room temperature. In this work, synthesis of the Sr₃Co₂Fe₂₄O₄₁ material following both citrate and Pechini methods is reported. X-ray diffraction patterns evidence that the obtained samples crystallize in hexagonal structures, belonging to the P63/mmc (#194) space group. Micrographs of scanning electron microscopy reveal the hexagonal characteristic of grains in the homogeneous and strongly densified surface. Measurements of magnetization as a function of applied fields show the ferromagnetic hysteretic behavior of material. Low-temperature curves of susceptibility (50 K < T < 350 K) exhibit irreversibility behavior, which is characteristic of disorder effects. An anomaly takes place at T = 230 K due to the occurrence of a crossover from a conical anisotropy (T < 230 K) to planar anisotropy (230 K > T > T_C). A drastic change in the thermogravimetric curve at T = 683 K is attributed to the loss of magnetic force caused by the transition between ferromagnetic and paramagnetic states.