Impedance of nanometer thickness ferromagnetic Co40Fe40B20 films
نویسندگان
چکیده
Nanocrystalline Co40Fe40B20 films, with film thickness tf = 100 nm, were deposited on glass substrates by the magnetron sputtering method at room temperature. During the film deposition period, a dc magnetic field, h = 40 Oe, was applied to introduce an easy axis for each film sample: one with h||L and the other with h||w, where L and w are the length and width of the film. Ferromagnetic resonance (FMR), ultrahigh frequency impedance (IM), dc electrical resistivity (ρ), and magnetic hysteresis loops (MHL) of these films were studied. From the MHL and r measurements, we obtain saturation magnetization 4πMs = 15.5 kG, anisotropy field Hk = 0.031 kG, and r = 168 mW.cm. From FMR, we can determine the Kittel mode ferromagnetic resonance (FMR-K) frequency fFMRK = 1,963 MHz. In the h||L case, IM spectra show the quasi-Kittel-mode ferromagnetic resonance (QFMR-K) at f0 and the Walker-mode ferromagnetic resonance (FMR-W) at fn, where n = 1, 2, 3, and 4. In the h||w case, IM spectra show QFMR-K at F0 and FMR-W at Fn. We find that f0 and F0 are shifted from fFMRK, respectively, and fn = Fn. The in-plane spin-wave resonances are responsible for those relative shifts.PACS No. 76.50.+q; 84.37.+q; 75.70.-i.
منابع مشابه
Spin filtering by ultrathin ferromagnetic films
Spin filtering of ballistic electrons by ultrathin cobalt films of thicknesses ranging from 0.2 to 3.5 nm has been studied experimentally using nonmagnetic metal–ferromagnet–superconductor nanocontacts. In such systems the flow of electrons with energies below the superconducting gap is very sensitive to any net spin polarization of the electron current. This effect was used to quantitatively m...
متن کاملOptically Transparent Ferromagnetic Nanogranular Films with Tunable Transmittance
Developing optically transparent magnets at room temperature is an important challenge. They would bring many innovations to various industries, not only for electronic and magnetic devices but also for optical applications. Here we introduce FeCo-(Al-fluoride) nanogranular films exhibiting ferromagnetic properties with high optical transparency in the visible light region. These films have a n...
متن کاملAn analytical model for ultrathin films with spatially varying magnetic anisotropies
The continuum theory of micromagnetism is used to study ultrathin films with magnetic anisotropy varying laterally on the nanometer scale. A series of infinitely long stripes with alternating inand out-of-plane uniaxial anisotropy is considered as a model for patterned ferromagnetic films. The analytical solution based on an effective anisotropy description of the dipolar energy is given as a f...
متن کامل6 J an 1 99 9 Thickness dependent Curie temperatures of ferromagnetic Heisenberg films
We develop a procedure for calculating the magnetic properties of a ferromagnetic Heisenberg film with single-ion anisotropy which is valid for arbitrary spin and film thickness. Applied to sc(100) and fcc(100) films with spin S = 7 2 the theory yields the layer dependent magnetizations and Curie temperatures of films of various thicknesses making it possible to investigate magnetic properties ...
متن کاملProton conductivity of columnar ceria thin-films grown by chemical vapor deposition.
Columnar thin films of undoped ceria were grown by metal-organic chemical vapor deposition. The films, deposited on Pt-coated MgO(100) substrates, display a columnar microstructure with nanometer scale grain size and ~30% overall porosity. Through-plane (thickness mode) electrical conductivity was measured by AC impedance spectroscopy. Proton conduction is observed below 350-400 °C, with a magn...
متن کامل