New Structure Disk for a Magneto-Optical Composite Head System

Koda, Tomohiro; Kawashima, Tetsuji; Fujita, Goro; Watanabe, Takahiro

doi:10.1143/jjap.31.551

Cited by 3 publications

(2 citation statements)

References 3 publications

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“…The difference of refractive index, Δ n = n ∥ − n ⊥ , was measured in an ultrasonically induced birefringence experiment, where n ∥ and n ⊥ are refractive indexes parallel and perpendicular to the direction of sound wave propagation, respectively. The details of the ultrasonically induced birefringence apparatus have been well described elsewhere. − The ultrasonic intensities in the sample cell are determined by measuring the light intensities of the Bragg diffraction…”

Section: Methodsmentioning

confidence: 99%

Dynamics of Entanglement Networks of Rodlike Micelles Studied by Measurements of Ultrasonically Induced Birefringence

et al. 1997

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Ultrasonically induced birefringence was observed on the entanglement networks of the rodlike micelles of hexadecyldimethylammine oxide and mixtures of hexadecyltrimethylammonium bromide and sodium salicylate. After the onset of ultrasound, the birefringence increased suddenly and approached a steady value after a damped oscillation. The steady value of the birefringence was proportional to the ultrasonic intensity and increased with the ultrasonic frequency. The birefringence of the entanglement networks is induced by the radiation pressure. The period of oscillation and damping time constant of birefringence were related respectively to the plateau modulus and the stress relaxation time obtained from rheological measurement.

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Section: Methodsmentioning

confidence: 99%

Dynamics of Entanglement Networks of Rodlike Micelles Studied by Measurements of Ultrasonically Induced Birefringence

et al. 1997

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“…Birefringence Measurement. Experimental details of the setup are described in our previous papers. , The direction of the incident light is perpendicular to the direction of the sound wave propagation. The light from a He−Ne laser (632.8 nm, 5 mW) passes through the polarizer with an angle of polarization at 45°, sample cell, λ/4 plate, and analyzer with a small offset angle β from its extinction position.…”

Section: Methodsmentioning

confidence: 99%

Frequency Dependence of Ultrasonically Induced Birefringence of Rodlike Particles

et al. 1996

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Ultrasonically induced birefringence of two rodlike particles of the hematite sols and the poly(tetrafluoroethylene) latex was investigated as a function of volume fraction, ultrasonic intensity, and frequency. The negative birefringence was observed for both samples, and the birefringence was proportional to the volume fraction and the ultrasonic intensity. The frequency dependence of the birefringence was observed in the wide ultrasonic frequency range from 5 to 225 MHz and did not agree with the Oka theory. The modified Oka theory for disclike particles was extended in view of application for rodlike particles. The birefringence measured was several tens of times larger than that calculated from the modified Oka theory for rodlike particles. The orientational relaxation time of the two particles estimated from the trace of the transient birefringence can be expressed in the form of the Debye-Einstein equation. IntroductionThe double refraction is induced in liquids and solutions containing a certain amount of nonspherical particles as a result of the particle orientation due to ultrasonic waves. This was called the phenomenon of the ultrasonically induced double refraction. 1 The early theoretical studies of the birefringence have been reviewed by Hilyard and Jerrard. 2 The theory developed by Oka 3 indicated that large disclike rigid particles align by hydrodynamic torque which is produced by the radiation pressure due to the passage of the ultrasonic wave. The normal of disclike particles is parallel to the ultrasonic field, and the sign of the birefringence of disclike particles is negative.The measurements of the birefringence of large rigid disclike particles were carried out on bentonite 4 and gold sols. 5,6 These experimental results show that the birefringence is proportional to the ultrasonic intensity as predicted by the Oka theory. However, the frequency dependence of the birefringence has been scarcely investigated because the measurements of the ultrasonic intensity at different frequencies are difficult. Recently, Ou-Yang et al. 7 made use of the Raman-Nath diffraction effect to measure the ultrasonic intensity at the frequency range from 1 to 19 MHz and investigated the ultrasonically induced birefringence of gold sols as a function of solvent viscosity, particle size, and ultrasonic intensity and frequency. The birefringence increased with increasing ultrasonic frequency and decreasing viscosity, and the sign of the birefringence was positive. They modified the Oka theory to explain the sign of the birefringence and the dependence of the birefringence on the frequency and viscosity.For large rigid rodlike particles, no theoretical study of the ultrasonically induced birefringence has been reported. Experimental investigations on the birefringence of V 2 O 5 sols 1, 8,9 have been carried out. Measurements 8 by Petralia on V 2 O 5 sols indicated that the birefringence depended on the viscosity and the sign of the birefringence was positive. In our previous paper, 9 the ultrasonically induced bire...

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