Dynamic magnetic properties of Fe₇₀Co₃₀(100) single-crystal thin films deposited at various substrate temperatures

Abstract

Abstract. Crystallographic orientation dependence of Gilbert damping constant, !, has been measured under different static magnetic fields for Fe 70 Co 30 (100) single-crystal thin film samples prepared at various substrate temperatures. Lorentz type resonance peaks are observed for the samples prepared below 200 ºC. For a sample deposited at 400 ºC, broadening of the resonance peak is observed, which is related with an increased surface roughness. ! value decreases monotonically with increasing the static field when the field is applied parallel to the easy magnetization axis, whereas it increases when the field is applied along the hard magnetization axis up to around the anisotropy field and then decreases. The minimum value of ! is determined to be 0.012 for the hard axis under static fields greater than 650 Oe. The value is twice larger compared with that of Fe (100)

Gilbert damping constant of FePd alloy thin films estimated by broadband ferromagnetic resonance

“…Resonant frequency is defined at the frequency where shows a maximum value. Solid lines show the calculated using best fitting parameters of M s , K 1 , and [7], where g-factor is fixed at 2.07 [2]. There are very good agreements between the experiments and the calculations for the as-deposited film and the film annealed at 300 ºC for the applied static magnetic field range, whereas for the film annealed at 400 ºC, good agreements are recognized only for more than 300 Oe.…”

“…Then, the films were annealed at 300 and 400 ºC for 1 h. The structural properties were investigated by RHEED and Xray diffraction (XRD) with Cu-K radiation ( = 0.15418 nm). GHz, where RF magnetic field was applied orthogonally to the static magnetic field using a shorted micro-strip line [7,8]. The resonant frequency was determined as a frequency when an experimental complex permeability, , showed a maximum value.…”

“…is calculated from the straight line fitting of the formula (1) with the measured f r dependence of H. H 0 is defined as the intercept from the straight fitting. On the other hand, damping constant, , is also evaluated by fitting the calculated to each absorption peak of experimental with best fitting parameters [7]. The line width of each absorption peak includes magnetic relaxation resulting from various factors.…”

“…%) alloy epitaxial thin films with very flat surfaces, which are obtained on MgO(001) singlecrystal substrates by employing a two-step process; lowtemperature deposition at 200 ºC followed by hightemperature annealing at 400 ºC [6]. Very flat surface is required in FMR measurements to evaluate intrinsic magnetic relaxation in order to avoid extrinsic effect by surface roughness [7]. Broadband FMR measurements using a VNA are carried out for 40nm thick films under static magnetic fields up to 1 kOe in the film plane to measure magnetic relaxation.…”

A review of high magnetic moment thin films for microscale and nanotechnology applications

“…To date, no other bulk material has been found to reliably exhibit higher saturation magnetisation at room temperature than Fe 2 Co. 35 Research is still ongoing to push the saturation of FeCo alloys beyond the present day limit, by creating pure single crystals of defined orientation 151 which do not suffer from moment losses due to grain boundaries, 152 or multi-layered systems. First-principle based modeling of ordered Fe-Co multilayers shows that the spin moment of Fe increases near the Fe-Co interface, while the Co spin moment decreases less, leading to a net increase in spin moment (see Fig.…”