Coplanar waveguide based ferromagnetic resonance in ultrathin film magnetic nanostructures: Impact of conducting layers

Abstract

We report broadband ferromagnetic resonance (FMR) measurements based on a coplanar waveguide (CPW) of ultrathin magnetic film structures that comprise in-plane/out-of-plane decoupled layers deposited on nonmagnetic buffer layers of various thickness or other buffer structures with a diverse sheet resistance. We show that the excitation of the fundamental mode can be substantially (up to 10 times) enhanced in the structures deposited on buffer layers with a low sheet resistance in comparison to the structures deposited on thin or weakly conducting buffer layers. The results are analyzed in terms of shielding of the electromagnetic field of CPW by the conducting buffer layers. The effect of enhancement of FMR absorption can be attractive for applications in spintronic devices that utilize magnetization dynamics of ultrathin ferromagnetic layers.

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

“…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.…”

On-wafer magnetic resonance of magnetite nanoparticles

“…As a simplification, the change in S-parameters with magnetic field ∆S 21 or ∆S 11 are also commonly used in the literature as a proportional mea-255 sure of the complex susceptibility [12,13,14,22 Both the lumped and distributed element models assume that the measurement device is perfectly calibrated and the probes are placed equidistant from the sample, i.e., the reference plane is deembedded to the edge of the sample [15]. In reality, 265 proper de-embedding of the sample is challenging.…”

“…The technique extends from previous work measuring the ferromagnetic resonance (FMR) of magnetic thin-films and other nanostructures by use of a combination of vector network analyzer (VNA) and coplanar waveguides (CPW), referred to in the 60 literature as VNA-FMR [12,13,14,15,16,17]. We compare the resonance spectra from cavitybased EPR and broadband on-wafer EPR using dilutions of ferumoxytol and TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl) in both frozen and dried states.…”

Miniaturized Coplanar Waveguide for Nanostructured Magnetostrictive Multilayer Characterization

“…Nevertheless, a reliable and authentic value of the permeability is very important for such applications. FMR based on a VNA and CPW has become a common experimental tool for studying magnetic films [3]. However, the necessity for an accurate and localized characterization of these materials in terms of electric and magnetic properties is still needed.…”