The effects of intraparticle and interparticle interactions on the magnetic hysteresis loop of frozen suspensions of magnetic nanoparticles
Cindi L. Dennis, Zoe Boekelheide, Jackson Miller, Cordula Gruettner
We present magnetic hysteresis loop measurements at 11 K on suspensions of magnetic nanoparticles dispersed in H2O which have been frozen in a range of applied magnetic fields. These particles exhibit significant interparticle as well as intraparticle magnetic interactions, which affect the shape of the hysteresis loop. To investigate the roles of particle orientation and particle chaining on the shape of the magnetic hysteresis loop, we represent the suspension with a micromagnetic model. We found that the hysteresis loop shape can be explained by effects of the internal parallelepiped-shaped magnetic domain structure, modified by the effects of interparticle interactions from chaining.