Ultrafast Dynamics of a Ferromagnetic Nanocomposite

Abstract

Ensembles of iron nanocrystals up to 25 nm in diameter embedded in SiO(2) were found to exhibit an ultrafast magnetic response to a transient out-of-plane magnetic field. The response time varies as a function of in-plane bias magnetic field with the fastest rise times, as short as 26 ps, observed for both zero and high bias fields (140 kA/m). Analytical modeling and micromagnetic simulations confirm that magnetostatic interactions between nanoparticles play an important role in the dynamic response.

Thermal annealing effect on magnetic properties of Fe nanoparticles implanted in yttrium-stabilized zirconia

“…Implanted ions often form a solid solution of isolated atoms in the host material prior to annealing, however, due to local heating effects during the implantation process, some iron nanocrystals have formed in the YSZ prior to annealing. 10 The total amount of asimplanted nanocrystalline iron is small, as the detected maximal Kerr rotation is about ten times smaller as compared to the annealed specimens as shown in Fig. 2͑a͒.…”

“…4 During the last a few years, a wide variety of magnetic alloys and nanocomposites have been fabricated using this technique. [5][6][7][8][9][10] In this paper, we present a study of iron nanocrystals into a single crystal yttriumstabilized zirconia substrate ͑Y 0.2 Zr 0.8 O 19 , YSZ͒ that fabricated using a combination of ion implantation and thermal treatment at different temperatures. The purpose of this study is to investigate the thermal annealing effect on the nanocrystal structures, magnetic hysteresis, and spin dynamics.…”

Multilayer route to iron nanoparticle formation in an insulating matrix

“…3 In recent years, various methods of nanocomposite fabrication have been developed, including evaporation, sputtering, ball milling, ion implantation, and microemulsions. [9][10][11][12][13][14][15] The particle size strongly depends on the preparation parameters and methods and can be difficult to control. Ion implantation was shown to produce metallic iron nanoparticles that exhibited large Faraday rotation and fast dynamic response, 5,13,16 but the size distribution was wide.…”

“…[9][10][11][12][13][14][15] The particle size strongly depends on the preparation parameters and methods and can be difficult to control. Ion implantation was shown to produce metallic iron nanoparticles that exhibited large Faraday rotation and fast dynamic response, 5,13,16 but the size distribution was wide. Effective size control has been pursued using self-assembly in ordered nanomaterials, [17][18][19] as well as chemical synthesis of monodispersed ferro/ferrimagnetic nanoparticles by reduction of metal salts and/or thermal decomposition of organometallic precursors.…”

Structure and Properties of Nanoparticles Formed by Ion Implantation

“…After [80] corporates a dynamical spin-rotation method based on the Landau-LifshitzGilbert equation and that includes a larger number of particles interacting in three dimensions, while computationally challenging, would provide considerable further understanding of the magnetic properties of these materials. Some of this work has already been started, and some unexpected results have been found, including ultrafast magnetic relaxation in iron nanocrystals formed by ion implantation that was attributed to cluster-cluster interactions [82], and a very large Faraday rotation [83]. With respect to applications, the ability to control the orientation and crystal structure of the ferromagnetic precipitates and the durable nature of the composites themselves are important advantages of the ion-implantation technique.…”