The influence of interparticle interaction on magnetization curves of nano-and microcrystal ensembles

Diagram of the magnetic state of real fine particle system of Ca<inf>0.5</inf>Ba<inf>0.5</inf>Fe<inf>12</inf>O<inf>19</inf>

“…Unlike the previous authors' works on the subject [1,2], where only the model nano-(d = 5 -100 nm) or microfine (d = 0.1 -1.4 ȝm) systems of ȼɚFe 12 O 19 hexaferrite with magnetic characteristics similar to the model and with quite well predicted behaviour in magnetic field by the known theoretical models were studied [3][4][5], in this paper a real system of biocompatible particles Ca 0.5 Ba 0.5 Fe 12 O 19 with a quite wide size distribution within the single domain limit is studying for the first time. The aim is to show how well the magnetic state of a particle system in general and the individual contribution of particles with different scale in the effective magnetic parameters of the powder sample can be analyzed.…”

“…The fields H H a min progressively suppresses the spatial fluctuations of the magnetic moment of particles, "linking" the magnetic moment to the field direction. For investigated system of particles, with real distribution of volume and magnetic anisotropy fields, transition from MS in to the SPM state is realized in a finite temperature interval limited by critical temperatures blocking the magnetic moment of the particle, T BH (1) and T BH (2) . The beginning of the transition corresponds to temperature T BH (1) (determined by the position of the minimum on the curve ı(T)), the end of the transition -T BH (2) (determined by the position of the maximum on this dependence).…”

“…Based on the dependencies T BH (1,2) = f(H) (H-T) diagram for the magnetic state of the system of particles was constructed. In Fig.…”

The exchange interaction effects on magnetic properties of the nanostructured CoPt particles

“…The effective magnetic anisotropy and the hysteresis loop shape would then be determined by the intergrain exchange interaction [18][19][20]. Qualitative investigation of the intercrystallite, intergrain or interphase interactions is frequently performed using the so called remanence magnetization curves or Henkel plots [21][22][23][24][25][26][27]. These methods are suitable for the weak interparticle ineractions case.…”