Viscosity 6. Flow of a Viscous Liquid Through a Tube 6. Heat Conduction 6. Heat Transfer Between Two Walls 6. Dissolution of a Solid in a Liquid Molecular Treatment of the Diffusion Process 6.
Relations Between Kinetic Coefficients Resistance to the Motion of Solids in a Liquid 6. Similitude Method. Drag at Low Velocities 6. Drag at High Subsonic Velocities Instabilities in Hydrodynamics 6 7. Transition from Laminar to Turbulent Flows 6. Boundary Layer 6.
Turbulent Viscosity and Thermal Diffusivity 6. Transition from Molecular to Convective Heat Transfer. Solar Granulation Oscillations and Waves in a Liquid 6. Various Forms of Wave Motion 6. Wave Characteristics 6. Linear and Nonlinear Waves 6. Solitons and Other Nonlinear Effects 6. Highly Perturbed Media 6. Macroscopic Motion of Compressible Media 6. Compressibility Criterion for a Medium and the Velocity of Sound 6.
Flow in a Tube with a Varying Cross Section 6. Laval Nozzle Shock Waves 6. General Relations for a Shock Wave 6. Shock Waves in an Ideal Gas 6. Hydrodynamic Cumulative Effects 6. Cumulative Jets 6. Bubble Collapse in a Liquid 6. Converging Spherical and Cylindrical Shock Waves 6. Emergence of a Shock Wave on the Surface of a Star Cavitation in a Liquid 6.
Highly Rarefied Gases 6. Macroscopic Quantum Effects in a Liquid 6. Generalizations of Hydrodynamics Chapter 7. Electromagnetic Fields in Media. Electrical, Magnetic, and Optical Properties of Substances Superconductivity 7. Electrical Conductivity of Metals 7. Direct Current Dielectric Conductance 7. Electrons and Holes. Exciton States 7. Semiconductors Electric Fields in Matter 7. Field Fluctuations in a Substance 7.
Electrostatic Fields in Metals 7. Electrostatic Fields in Insulators. A Substance in a Magnetic Field 7. Diamagnetic Effect 7.
Orientation Magnetization 7. Spontaneous Magnetization. Magnetic Properties of Superconductors. Quantization of Large-Scale Magnetic Flux Alternating Currents and Electromagnetic Waves in a Medium. Share This Paper. Background Citations. Methods Citations. Results Citations. Citation Type. Has PDF. Publication Type. More Filters. Magnetic oscillations and the quasiparticle bands of heavy electron systems.
Abstract Studies of the quasiparticle band structure in a series of heavy electron metals have been performed by means of angle resolved measurements of the de Haas-van Alphen effect in pure … Expand. Sign up Log in. Web icon An illustration of a computer application window Wayback Machine Texts icon An illustration of an open book. Books Video icon An illustration of two cells of a film strip. The magnetic oscillation element according to the first embodiment includes a lower electrode 3 provided on a substrate 1 and also serving as a magnetic shield, a magnetization free layer 5 provided on the lower electrode 3 with the magnetization direction being substantially perpendicular to the film surface, a non-magnetic layer 7 provided on the magnetization free layer 5 , a magnetization fixing layer 9 provided on the non-magnetic layer 7 with the magnetization direction being substantially perpendicular to the film surface, and an upper electrode 11 provided on the magnetization fixing layer 9 and also serving as a magnetic shield.
The magnetization free layer 5 , the non-magnetic layer 7 , and the magnetization fixing layer 9 form a stacked film 4 with the same flat surface shape. The magnetization direction of each of the magnetization free layer 5 and the magnetization fixing layer 9 is substantially perpendicular to the film surface, namely, the easy axis of magnetization is substantially perpendicular to the film surface.
In the first embodiment, a perpendicular magnetization film is used as the magnetization free layer 5 , whereby the magnetic field dependency of the perpendicular magnetization film is indicated by Expression 6.
Since the magnetic field dependency decreases to about one-fifth of the magnetic field dependency of the in-plane magnetization film, the signal purity becomes almost five times that of the in-plane magnetization film. The magnetic oscillation element according to the second embodiment includes a lower electrode 3 provided on a substrate 1 and also serving as a magnetic shield, a magnetization free layer 5 provided on the lower electrode 3 with the magnetization direction being substantially horizontal to the film surface, a non-magnetic layer 7 provided on the magnetization free layer 5 , a magnetization fixing layer 9 provided on the non-magnetic layer 7 with the magnetization direction being substantially horizontal to the film surface, and an upper electrode 11 provided on the magnetization fixing layer 9 and also serving as a magnetic shield.
The magnetization direction of each of the magnetization free layer 5 and the magnetization fixing layer 9 is substantially horizontal to the film surface, namely, the easy axis of magnetization is substantially horizontal to the film surface. In the second embodiment, an in-plane magnetization film having crystal anisotropy, of a proper size such as a Co film having a proper film thickness is used as the magnetization free layer 5.
In such an in-plane magnetization film, the magnitude of a demagnetizing field H d is represented by Expression 7 as the difference between shape anisotropy magnetic field 4 nM and crystal anisotropy magnetic field Hk1 and thus a magnetization free layer material and its film thickness are appropriately selected, whereby H d can be decreased and the magnetic field dependency of oscillatory frequency can be decreased.
If H d is decreased to several Oe, the magnetic field dependency of oscillatory frequency is given approximately by Expression 5. The magnetic oscillation element according to the embodiment includes a lower electrode 3 provided on a substrate 1 and also serving as a magnetic shield, a magnetization free layer 5 provided on the lower electrode 3 with the magnetization direction being substantially parallel to the film surface, a non-magnetic layer 7 provided on the magnetization free layer 5 , a magnetization fixing layer 9 provided on the non-magnetic layer 7 with the magnetization direction being substantially parallel to the film surface, and an upper electrode 11 provided on the magnetization fixing layer 9 and also serving as a magnetic shield.
The magnetization direction of each of the magnetization free layer 5 and the magnetization fixing layer 9 is substantially perpendicular to the film surface, namely, the easy axis of magnetization is substantially parallel to the film surface. In the third embodiment, an artificial ferrimagnetic substance is used as the magnetization free layer 5. Since the effective saturation magnetization in such an artificial ferrimagnetic substance is given by Expression 8 , the difference between thicknesses t 1 and t 2 is lessened, whereby effective saturation magnetization M ferri can be decreased and the demagnetizing field can be decreased.
The magnetic field dependency of oscillatory frequency in the artificial ferrimagnetic substance is also given approximately by Expression 6. To use the artificial ferrimagnetic substance as the magnetization free layer, it is also effective to cause an exchange bias to act on the magnetization free layer directly or through the non-magnetic layer 7 using an antiferromagnetic layer 8 as shown in FIG.
Since an extremely large exchange bias can be caused to act on the artificial ferrimagnetic substance, the oscillatory frequency can be raised to about GHz and the Q value of oscillation given in Expression 9 can be increased. The magnetization direction of each of the magnetization free layer 5 and the magnetization fixing layer 9 is substantially parallel to the film surface, namely, the easy axis of magnetization is substantially parallel to the film surface.
In the fourth embodiment, an artificial antiferromagnetic substance is used as the magnetization free layer 5. To use such an artificial antiferromagnetic substance, Expression 10 is made possible, so that it is made possible to remarkably decrease the oscillation line width to one-tenth that when a perpendicular magnetization film is used or to about one-fiftieth that when an in-plane magnetization film is used.
Further, a similar magnetization free layer structure is also effective in an element in FIG. With the elements in FIGS. Unlike a usual electric oscillator, the magnetic oscillation element converts motion of magnetization into electric vibration according to the GMR effect and outputs the result as electric power. That is, since negative resistance existing in an electric oscillator does not exist, impedance matching with a transmission line or load becomes extremely important.
That is, it is desirable that the element should be connected so as to become equal to the characteristic impedance of the transmission line, but the element can be built directly in the transmission line because it is a minute element. Next, examples according to the invention will be discussed. A stacked film was formed on a sapphire substrate 1 using sputter deposition and electron-beam lithography.
The stacked film has a nonmagnetic layer 3 made of Ru, a ferromagnetic magnetization free layer 5 made of Co, a nonmagnetic layer 7 made of Cu, an NOL layer 15 formed by oxidizing the top face portion of the nonmagnetic layer 7 , a ferromagnetic magnetization fixing layer 9 made of FePt, and a nonmagnetic layer 11 made of Cu in order from the side of a substrate 1.
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