Microwave properties of Ni-based ferromagnetic inverse opals

作者：Kostylev M^*; Stashkevich A A; Roussigne Y; Grigoryeva N A; Mistonov A A; Menzel D; Sapoletova N A; Napolskii K S; Eliseev A A; Lukashin A V; Grigoriev S V; Samarin S N

来源：Physical Review B, 2012, 86(18): 184431.

DOI：10.1103/PhysRevB.86.184431

Investigations of microwave properties of Ni-based inverse ferromagnetic opal-like film with the [111] axis of the fcc structure along the normal direction to the film have been carried out in the 2-18 GHz frequency band. We observed multiple spin wave resonances for the magnetic field applied perpendicular to the film, i.e., along the [111] axis of this artificial crystal. For the field applied in the film plane, a broad band of microwave absorption is observed, which does not contain a fine structure. The field ranges of the responses observed are quite different for these two magnetization directions. This suggests a collective magnetic ground state or shape anisotropy and collective microwave dynamics for this foam-like material. This result is in agreement with SQUID measurements of hysteresis loops for the material. Two different models for this collective behavior are suggested that satisfactorily explain the major experimental results.

• 出版日期2012-11-29