Magnetic interaction and investment of the magnetization in Ferrites BaM

Presents a study on coercivity mechanisms in strotium of barium M-type, obtained by chemical co-precipitation method and traditional ceramic method. As basic characterization techniques were used the diffraction of x-rays (DRX) and the scanning microscopy (SEM); magnetic measurements were performed using the vibrational magnetometer (VSM). The volumes of activation from measurements of magnetic viscosity were calculated and obtained information about interactions particula-particula from the curved top of remanence. For the coprecipitada sample was determined a coercive field Hc = 5700 Oe at room temperature and particle d size = 180 nm, below the critical size monodominio. Both the initial magnetization curve and called Henkel graph for this sample are consistent with the predictions of the model of consistent rotation of Stoner and Wohlfarth particulate monodominio, uniaxial and not interacting. The ceramic sample has a coercive 3200 Oe and initial magnetization curve suggests the existence of a mechanism of magnetization by domain nucleation. However, the volumes of activation were similar for the two samples and younger than particle sizes observed in each case, which points to a mechanism of coercivity unlike the coherent rotation for coprecipitada sample.