Strong Eddy-Current Shielding of Ferromagnetic Resonance Response in Sub-Skin-Depth-Thick Conducting Magnetic Multilayers

Physica E: Low-dimensional Systems and Nanostructures

2015

Self Cite

154

149

This article presents a comprehensive critical overview of fundamental and practical aspects of the modern stripline broadband ferromagnetic resonance (BFMR) spectroscopy largely employed for the characterisation of magnetic low-dimensional systems, such as thin ferro-and ferromagnetic, multiferroic and half-metallic films, multi-layers and nanostructures. These planar materials form the platform of the nascent fields of magnonics and spintronics. Experimental and theoretical results of research on these materials are summarised, along with systematic description of various phenomena associated with the peculiarities of the stripline BFMR, such as the geometry of stripline transducers, the orientation of the static magnetic field, the presence of microwave eddy currents, and the impacts of non-magnetic layers, interfaces and surfaces in the samples. Results from more than 240 articles, textbooks and technical reports are presented and many practical examples are discussed in detail. This review will be of interest to both general physical audience and specialists conducting research on various aspects of magnetisation dynamics and nanomagnetism.

Section: Fig 39mentioning

confidence: 63%

Section: Shielding Of the Microwave Electromagnetic Field Of Striplinmentioning

confidence: 76%

See 1 more Smart Citation

Broadband stripline ferromagnetic resonance spectroscopy of ferromagnetic films, multilayers and nanostructures

Maksymov

Physica E: Low-dimensional Systems and Nanostructures

2015

Self Cite

154

149

“…Then, from the analogy with Fig. 1(b) in [52] one may expect that the eddy currents and hence the total microwave magnetic field is larger in the Fe layer than in the Permalloy one. Since the magnetization precession in metallic materials is driven by the total microwave magnetic field [46], one may expect that the microwave driving field is stronger in the Fe layer than in the Permalloy one.…”

Section: B Most General Details Of the Theory Of The Magnetization Dmentioning

confidence: 78%

Microwave magnetic dynamics in ferromagnetic metallic nanostructures lacking inversion symmetry

Journal of Applied Physics

Yang

Maksymov

et al. 2016

In this work we carried out systematic experimental and theoretical investigations of the ferromagnetic resonance (FMR) response of quasi-twodimensional magnetic nano-objects -microscopically long nanostripes made of ferromagnetic metals. We were interested in the impact of the symmetries of this geometry on the FMR response. Three possible scenarios, from which the inversion symmetry break originated were investigated: (1) from the shape of the stripe crosssection, (2) from the double-layer structure of the stripes with exchange coupling between the layers, and (3) from the single-side incidence of the microwave magnetic field on the plane of the nano-pattern. The latter scenario is characteristic of the stripline FMR configuration. It was found that the combined effect of the three symmetry breaks is much stronger than impacts of each of these symmetry breaks separately. I. IntroductionFerromagnetic resonance (FMR) is a powerful tool for studying dynamic properties of metallic ferromagnetic thin films and nanostructures (see e.g., Refs. [1][2][3][4][5][6][7][8][9][10][11][12]). These materials are important for the emerging fields of magnonics [13], microwave spintronics [14][15][16][17], and for novel sensor applications [18][19][20][21].Macroscopically-long stripes with sub-micron cross-section made of ferromagnetic materials have attracted a lot of attention, because this geometry is a very convenient model object for studying the impact of geometric confinement on magnetization dynamics on the sub-micrometre and nanometer scales [22][23][24][25][26][27][28][29][30]. The main reasons for the attractiveness of this geometry are the practical absence of a static demagnetizing field H ds when the external field is applied along the stripes (i.e. along the axis y in Fig. 1(a)) and the quasi-two-dimensional (2D) character of the dynamics.The former property allows clear separation of the static and dynamic demagnetizing effects. Furthermore, because of the absence of H ds , the static magnetization configuration for the stripes is very simple. The static magnetization vector has the same magnitude -equal to the saturation magnetization for the material -and the same direction -along the stripe -for every point on the stripe crosssection. Due to strong shape anisotropy for this geometry, this configuration remains very stable even at remanence [29][30][31]. The simplicity of the magnetization ground state, together with the 2D character of the magnetization dynamics, results in simple analytical and quasi-analytical theoretical models able to deliver a clear physical

“…The microwave conductivity contribution to the stripline broadband ferromagnetic resonance (FMR) response of highly-conducting (metallic) magnetic multilayers and nanostructures of sub-skin-depth thicknesses has attracted significant attention in recent years [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. It has been shown that these effects are important when the microwave magnetic field is incident on only one of the two surfaces of a planar metallic material (see e.g.…”

Section: Introductionmentioning

confidence: 99%

Coupling of microwave magnetic dynamics in thin ferromagnetic films to stripline transducers in the geometry of the broadband stripline ferromagnetic resonance

Journal of Applied Physics

2016

Abstract. We constructed a quasi-analytical self-consistent model of the striplinebased broadband ferromagnetic resonance (FMR) measurements of ferromagnetic films. Exchange-free description of magnetization dynamics in the films allowed us to obtain simple analytical expressions. They enable quick and efficient numerical simulations of the dynamics. With this model we studied the contribution of radiation losses to the ferromagnetic resonance linewidth, as measured with the stripline FMR. We found that for films with large conductivity of metals the radiation losses are significantly smaller than for magneto-insulating films. Excitation of microwave eddy currents in these materials contributes to the total microwave impedance of the system. This leads to impedance mismatch with the film environment resulting in decoupling of the film from the environment and, ultimately, to smaller radiation losses. We also show that the radiation losses drop with an increase in the stripline width and when the sample is lifted up from the stripline surface. Hence, in order to eliminate this measurement artefact one needs to use wide striplines and introduce a spacer between the film and the sample surface. The radiation losses contribution is larger for thicker films.