1 Department of Physics, Technical University of Denmark2 Experimental Surface and Nanomaterials Physics, Department of Physics, Technical University of Denmark3 Center for Electron Nanoscopy, Technical University of Denmark4 DTU Admission Course, Technical University of Denmark
Spin structures in nanoparticles of ferrimagnetic materials may deviate locally in a nontrivial way from ideal collinear spin structures. For instance, magnetic frustration due to the reduced numbers of magnetic neighbors at the particle surface or around defects in the interior can lead to spin canting and hence a reduced magnetization. Moreover, relaxation between almost degenerate canted spin states can lead to anomalous temperature dependences of the magnetization at low temperatures. In ensembles of nanoparticles, interparticle exchange interactions can also result in spin reorientation. Here, we give a short review of anomalous spin structures in nanoparticles.