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Studies of Preparations, Structures and Properties of Nano-composite Magnetic Thin Films

Author: LiangRuiSheng
Tutor: ShiWangZhou;HuangLi
School: Shantou University
Course: Materials Physics and Chemistry
Keywords: Nanocrystalline soft magnetic thin films Microstructures Magnetic moment orientation Macroscopic magnetic
CLC: TB383
Type: Master's thesis
Year: 2004
Downloads: 162
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Abstract


Magnetic materials giant magnetoresistance (GMR) and giant magneto-impedance (GMI) effect in the field of magnetic measurements and magnetic recording has broad application prospects. The nanocrystalline soft magnetic material because of its excellent magnetic properties and sensitivity and attention. This article describes the use of magnetron sputtering nanocrystalline soft magnetic thin film methods, principles and processes, application of XRD and Mssbauer spectrum test methods to characterize the structure of nanocrystalline soft magnetic thin film. The main results are as follows: (1) the use of RF magnetron sputtering of Fe-Si-B-Nb-Cu film, RF sputtering power on the structure and properties of thin films. The results showed that: a low sputtering power density, the thin film is an amorphous structure; as the sputtering power density increased, the deposited films without heat treatment, are showing a mixed phase of crystalline and amorphous structure, crystalline nanoscale α-Fe (Si) and the α-Fe (B) a solid solution. With the improvement of the sputtering power, the volume fraction of the amorphous phase is gradually reduced, and the volume fraction of α-Fe (Si) phase and α-Fe (B) is gradually increased. α-Fe (B), the B atom occupation probability with increasing sputtering power is increased, resulting in α-Fe (B) phase hyperfine field decreased: 50, 100, 150 and 200W corresponding to the hyperfine The field of 235KOe, 229KOe, 223KOe 218KOe. (2) the magnetic moment of alignment of the film with the sputtering power. The angle between the magnetic moments alignment with the membrane surface normal with the rise of the power becomes small, when the sputtering power is small, the magnetic moment parallel to the film surface with increasing sputtering power, the magnetic moment of alignment with the membrane surface method to the angle between the gradually reduced. (3) through exclusive to the magnetization, studied the influence of the magnetic moments of orientation on the magnetic properties of thin film, the results show that: the remanence ratio is increased as the angle between the direction of the magnetic moment of alignment with the magnetization becomes small. This indicates that the magnetic properties of the film sample is closely related with the anisotropy of the grains. (4) The sputtering power was 400W, the film samples prepared as nanocrystalline composite mosaic structure of the Si-rich Si (Fe) and Fe-rich Fe (Si). Since the deposition of Si-based solid solution, the existence of a pinning effect, and α-Fe (Si) having a soft magnetic characteristics decrease in proportion of nanocrystalline solid solution in the sample, resulting in the change of the magnetic energy of the sample. (5) the use of the RF magnetron sputtering get cross with DC magnetron sputtering deposition preparation, NiFe / Ge multilayers by XRD, m (o) ssbauer spectrum and VSM analysis showed that: the samples (a) NiFe-based and Fe-based solid solution nanocrystalline and amorphous matrix composite mosaic structure, showed soft magnetic properties; while sample (b) in the presence of Fe, Ni, Ge three single quality nanocrystals, and the of NiFe, FeGe, FeGeNi alloy nanocrystals phase, the formation of the nano-crystalline and amorphous composite mosaic structure, part of the grains are paramagnetic, NiFe, FeGeNi as soft magnetic and hard magnetic phase precipitation, a corresponding increase of the coercive force and Hsat (~ 2200e) . Description exchange coupling exists between the hard magnetic phase and soft magnetic phase, and the pinning effect, causing the demagnetization mechanism of the film and the magnetization mechanism inconsistencies.

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