H. Fujimori

Nanocrystalline materials exhibit remarkable structural, electrical, magnetic, and optical properties, which can be exploited in a wide variety of structural and nonstructural applications. Potential uses have been identified in the automotive, electronic, aerospace, clothing, chemical, fuel, and lubrication industries, with applications ranging from flat panel displays to medical implants. Bringing together contributions from leading researchers in academia and industry throughout Europe and Japan, Novel Nanocrystalline Alloys and Magnetic Nanomaterials presents a valuable overview of this fast moving field. Divided into three sections, the book first describes the fabrication and structural characterization of nanocrystalline and amorphous alloys, such as aluminium, nickel, copper, titanium, and zirconium. The second part examines novel nanocrystalline materials that include nano-optoelectronics, steels manufactured by heavy plastic deformation, and metal-ceramic and ceramic-ceramic nanocomposites. The final section reviews the current understanding of magnetic nanomaterials, including nanograined materials, Ni and Fe nanocrystals, soft magnetic Fe-M-B nanocrystalline alloys, and soft and hard ferromagnetic nanocrystalline alloys. It also explores the industrial applications of these nanomaterials, focusing on their use in the energy and telecommunications fields. Combining key coverage of topical developments with well-informed indications of potential trends, this book lays the groundwork for future advances in nanocrystalline alloys and magnetic nanomaterials. Nanocrystalline materials exhibit remarkable structural, electrical, magnetic, and optical properties, which can be exploited in a wide variety of structural and nonstructural applications. Potential uses have been identified in the automotive, electronic, aerospace, clothing, chemical, fuel, and lubrication industries, with applications ranging from flat panel displays to medical implants. Bringing together contributions from leading researchers in academia and industry throughout Europe and Japan, Novel Nanocrystalline Alloys and Magnetic Nanomaterials presents a valuable overview of this fast moving field. Divided into three sections, the book first describes the fabrication and structural characterization of nanocrystalline and amorphous alloys, such as aluminium, nickel, copper, titanium, and zirconium. The second part examines novel nanocrystalline materials that include nano-optoelectronics, steels manufactured by heavy plastic deformation, and metal-ceramic and ceramic-ceramic nanocomposites. The final section reviews the current understanding of magnetic nanomaterials, including nanograined materials, Ni and Fe nanocrystals, soft magnetic Fe-M-B nanocrystalline alloys, and soft and hard ferromagnetic nanocrystalline alloys. It also explores the industrial applications of these nanomaterials, focusing on their use in the energy and telecommunications fields. Combining key coverage of topical developments with well-informed indications of potential trends, this book lays the groundwork for future advances in nanocrystalline alloys and magnetic nanomaterials. Nanocrystalline materials exhibit remarkable structural, electrical, magnetic, and optical properties, which can be exploited in a wide variety of structural and nonstructural applications. Potential uses have been identified in the automotive, electronic, aerospace, clothing, chemical, fuel, and lubrication industries, with applications ranging from flat panel displays to medical implants. Bringing together contributions from leading researchers in academia and industry throughout Europe and Japan, Novel Nanocrystalline Alloys and Magnetic Nanomaterials presents a valuable overview of this fast moving field. Divided into three sections, the book first describes the fabrication and structural characterization of nanocrystalline and amorphous alloys, such as aluminium, nickel, copper, titanium, and zirconium. The second part examines novel nanocrystalline materials that include nano-optoelectronics, steels manufactured by heavy plastic deformation, and metal-ceramic and ceramic-ceramic nanocomposites. The final section reviews the current understanding of magnetic nanomaterials, including nanograined materials, Ni and Fe nanocrystals, soft magnetic Fe-M-B nanocrystalline alloys, and soft and hard ferromagnetic nanocrystalline alloys. It also explores the industrial applications of these nanomaterials, focusing on their use in the energy and telecommunications fields. Combining key coverage of topical developments with well-informed indications of potential trends, this book lays the groundwork for future advances in nanocrystalline alloys and magnetic nanomaterials. Nanocrystalline materials exhibit remarkable structural, electrical, magnetic, and optical properties, which can be exploited in a wide variety of structural and nonstructural applications. Potential uses have been identified in the automotive, electronic, aerospace, clothing, chemical, fuel, and lubrication industries, with applications ranging from flat panel displays to medical implants. Bringing together contributions from leading researchers in academia and industry throughout Europe and Japan, Novel Nanocrystalline Alloys and Magnetic Nanomaterials presents a valuable overview of this fast moving field. Divided into three sections, the book first describes the fabrication and structural characterization of nanocrystalline and amorphous alloys, such as aluminium, nickel, copper, titanium, and zirconium. The second part examines novel nanocrystalline materials that include nano-optoelectronics, steels manufactured by heavy plastic deformation, and metal-ceramic and ceramic-ceramic nanocomposites. The final section reviews the current understanding of magnetic nanomaterials, including nanograined materials, Ni and Fe nanocrystals, soft magnetic Fe-M-B nanocrystalline alloys, and soft and hard ferromagnetic nanocrystalline alloys. It also explores the industrial applications of these nanomaterials, focusing on their use in the energy and telecommunications fields. Combining key coverage of topical developments with well-informed indications of potential trends, this book lays the groundwork for future advances in nanocrystalline alloys and magnetic nanomaterials. Nanocrystalline materials exhibit remarkable structural, electrical, magnetic, and optical properties, which can be exploited in a wide variety of structural and nonstructural applications. Potential uses have been identified in the automotive, electronic, aerospace, clothing, chemical, fuel, and lubrication industries, with applications ranging from flat panel displays to medical implants. Bringing together contributions from leading researchers in academia and industry throughout Europe and Japan, Novel Nanocrystalline Alloys and Magnetic Nanomaterials presents a valuable overview of this fast moving field. Divided into three sections, the book first describes the fabrication and structural characterization of nanocrystalline and amorphous alloys, such as aluminium, nickel, copper, titanium, and zirconium. The second part examines novel nanocrystalline materials that include nano-optoelectronics, steels manufactured by heavy plastic deformation, and metal-ceramic and ceramic-ceramic nanocomposites. The final section reviews the current understanding of magnetic nanomaterials, including nanograined materials, Ni and Fe nanocrystals, soft magnetic Fe-M-B nanocrystalline alloys, and soft and hard ferromagnetic nanocrystalline alloys. It also explores the industrial applications of these nanomaterials, focusing on their use in the energy and telecommunications fields. Combining key coverage of topical developments with well-informed indications of potential trends, this book lays the groundwork for future advances in nanocrystalline alloys and magnetic nanomaterials. Nanocrystalline materials exhibit remarkable structural, electrical, magnetic, and optical properties, which can be exploited in a wide variety of structural and nonstructural applications. Potential uses have been identified in the automotive, electronic, aerospace, clothing, chemical, fuel, and lubrication industries, with applications ranging from flat panel displays to medical implants. Bringing together contributions from leading researchers in academia and industry throughout Europe and Japan, Novel Nanocrystalline Alloys and Magnetic Nanomaterials presents a valuable overview of this fast moving field. Divided into three sections, the book first describes the fabrication and structural characterization of nanocrystalline and amorphous alloys, such as aluminium, nickel, copper, titanium, and zirconium. The second part examines novel nanocrystalline materials that include nano-optoelectronics, steels manufactured by heavy plastic deformation, and metal-ceramic and ceramic-ceramic nanocomposites. The final section reviews the current understanding of magnetic nanomaterials, including nanograined materials, Ni and Fe nanocrystals, soft magnetic Fe-M-B nanocrystalline alloys, and soft and hard ferromagnetic nanocrystalline alloys. It also explores the industrial applications of these nanomaterials, focusing on their use in the energy and telecommunications fields. Combining key coverage of topical developments with well-informed indications of potential trends, this book lays the groundwork for future advances in nanocrystalline alloys and magnetic nanomaterials.

In this paper, we present our detailed work of the microstructural characterization, using transmission electron microscopy (TEM), high resolution TEM and small angle X-ray scattering (SAXS). The effect of oxygen on the microstructure and the relationship between the microstructure and magnetic properties are clarified. The effect of annealing on the magnetic properties and microstructure has also been studied. Author(s) Xiong, X.Y. Nat. Inst. for Mater. Sci., Tsukuba, Japan Ohnuma, M. ; Ohkubo, T. ; Ping, D.H. ; Hono, K. ; Ohnuma, S. ; Fujimori, H. ; Masumoto, T.

Spin-dependent single-electron tunnelling phenomena have been investigated in current-perpendicular-to-plane geometry for insulating granular systems. The sample structure consists of a 7–12-nm-thick Co–Al–O granular film sandwiched by the top and bottom electrodes. A very thin Al–O layer has been added between the bottom electrode and the granular film as a bottleneck of conductance, leading to the successful observation of Coulomb staircases in the current–bias voltage I–V_b characteristics. The V_b dependence of tunnel magnetoresistance (TMR) shows clear oscillatory behaviour associated with the Coulomb staircase. The TMR oscillation is interpreted as a phenomenal characteristic of spin-dependent single-electron tunnelling.

We have investigated temperature and bias-voltage dependence of tunnel-type giant magnetoresistance (MR) in Co–Al–O insulating granular films. A remarkable enhancement of MR which is larger than the theoretical value by a simple model is observed for Co–Al–O granular films at low temperatures, and it steeply decreases with increasing temperature. On the other hand, the MR does not decrease with increasing bias voltage although the resistivity decreases by a few orders of magnitude. Furthermore, it has been found that the effect of temperature is definitely different from that of bias voltage. The anomalous behavior is in contrast to that of macroscopic tunnel junctions, suggesting the significant effect of Coulomb blockade in granular systems.

Giant magnetoresistance (GMR, large negative and isotropic magnetoresistance) arising from a spin‐dependent tunneling effect has been found in metal–nonmetal granular systems exhibiting extremely high electrical resistivities. These granular materials are reactively sputtered Co–(Al, Si)–O and Fe–Mg–O thin films, having a two phase nanostructure consisting of the Co (or Fe) rich metallic and magnetic grains and the Al (or Si,Mg) oxide narrow intergrains. These films possess large specific electrical resistivities(ρ₀) of 10⁴–10⁶ μΩ cm at room temperature, and show remarkable magnetoresistance (Δρ/ρ₀) whose values are about 8% in maximum at room temperature and at about 10 kOe of applied magnetic field. With decreasing temperature, Δρ/ρ₀ and ρ₀ increase. The temperature dependence of ρ₀ can be expressed in terms of log ρ₀∝T^−1.2, and the electrical current versus applied electrical voltage does not follow the ohmic low. We consider that a spin‐ dependent tunneling conductance in the path of magnetic grains–nonmetallic intergrains–magnetic grains is responsible for the observed GMRs accompanying high electrical resistivities. The details of these transport properties and the related magnetization and structural properties will be presented.

Fe-N films were synthesized by means of ion beam deposition. Nitridation was performed using an assist gun during the sputtering of Fe films. The as-deposited Fe-N films consisted of two phases, μ-Fe and γ'-Fe4N, and had a high coercive force Hc of over 20 Oe. When the films were annealed in vacuum, their Hc improved drastically, and had a minimum value of less than 1 Oe at 400°C. The films also had a high permeability of over 2000 as well as high resistivity (around 80 μΩ-cm), in spite of a high saturation magnetization (around 18 kG). The small grain size and stress relaxation in the films are closely related to the soft magnetic properties. The volume fraction of the γ'-Fe4N phase also affected the decrease in Hc, because the anisotropy normal to the film plane is reduced by increasing the magnetostatic energy when the volume fraction was 0.5.