Nanocrystallization in FINEMET-Type Fe73.5Nb3Cu1Si13.5B9 and Fe72.5Nb1.5Mo2Cu1.1Si14.2B8.7 Thin Films

Abstract

A growing variety of microelectronic devices and magnetic field sensors as well as a trend of miniaturization demands the development of low-dimensional magnetic materials and nanostructures. Among them, soft magnetic thin films of Finemet alloys are appropriate materials for sensor and actuator devices. Therefore, one of the important directions of the research is the optimization of thin film magnetic properties. In this study, the structural transformations of the Fe73.5Nb3Cu1Si13.5B9 and Fe72.5Nb1.5Mo2Cu1.1Si14.2B8.7 films of 100, 150 and 200 nm thicknesses were comparatively analyzed together with their magnetic properties and magnetic anisotropy. The thin films were prepared using the ion-plasma sputtering technique. The crystallization process was studied by certified X-ray diffraction (XRD) methods. The kinetics of crystallization was observed due to the temperature X-ray diffraction (TDX) analysis. Magnetic properties of the films were studied by the magneto-optical Kerr microscopy. Based on the TDX data the delay of the onset crystallization of the films with its thickness decreasing was shown. Furthermore, the onset crystallization of the 150 and 200 nm films began at the temperature of about 400–420 °C showing rapid grain growth up to the size of 16–20 nm. The best magnetic properties of the films were formed after crystallization after the heat treatment at 350–400 °C when the stress relaxation took place.

Transmission, Reflection and Dissipation of Microwaves in Magnetic Composites with Nanocrystalline Finemet-Type Flakes

“…It follows from Equation ( 16) that a monotonic decreasing thickness dependence of the transmission coefficient should exist. Curiously, it is found that, in this case of strong absorption, the reflection coefficient almost does not depend on the thickness of the plate that declares Equation (17).…”

“…The measurements of the magnetic properties of powdered Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 nanostructured alloy have been carried out in the frequency range 0.2-10.2 GHz [16]. Optimization of magnetic properties and magnetic anisotropy of thin, soft magnetic films of finemet alloys is accomplished [17]. The 100-200 nm films are found to be appropriate materials for sensor and actuator devices.…”

Ferromagnetic Resonance and Antiresonance in Composite Medium with Flakes of Finemet-Like Alloy

“…Metallic particles are in the form of flakes of the finemet-type alloy with the following composition: Fe—80.1%, Si—8.5%, Nb—8.4%, Cu—1.1%, B—1.2%, Cr—0.2%, Mn—0.1%, Ni—0.1% and Co—0.3%. As known, the nanocrystalline finemet-type alloy has high magnetic permeability [ 14 ].…”

“…Near the field of ferromagnetic resonance, however, the real and imaginary parts of the complex refraction coefficient are of the same order of magnitude, such as in a conductive medium. The magnetic properties of powdered nanostructured alloy Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 have been studied in the frequency range 0.2–10.2 GHz [ 14 ].…”

Specific Features of Structure Transformation and Properties of Amorphous-Nanocrystalline Alloys

“…As a result, during crystallization of the amorphous Fe-Cu-Nb-Si-B alloy, a microstructure with a crystal size of about 10 nm was obtained. Nanocrystalline alloys of the Fe-CuNb-Si-B system have excellent magnetic properties and a huge amount of work has been devoted to their study [92][93][94][95][96][97]. Later, a number of alloys were obtained in the nanocrystalline state by the controlled crystallization of the amorphous phase.…”