X-cut Quartz Research Articles

Method for measurement of anisotropic electrical conductivities of insulating film

Measurement of anisotropic electrical conductivities along main axes of insulating film is possible by measuring current flow parallel to the film surface, in which the four-electrode system attached symmetrically to both sides of a film is used. The method is experimentally verified by determining the conductivities of Z-cut and X-cut quartz crystals.

Observations of phonon focusing in x-cut quartz crystal

In the time-of-flight experiment with X-cut quartz crystal, in addition to the normal phonon pulses of L, T1 and T2 mode, a pulse of oblique mode was observed, which can be explained according to the phonon focusing effect.

Ultrasonic generation by spin wave resonance in evaporated 85% Ni-Fe alloy films

The experiments of ultrasonic generation by spin wave resonance were performed at 9.368 GHz in evaporated 85% Ni-Fe thin films with various thickness onto x-cut quartz. The microwave echo generated by ultrasonic waves was observed at the resonance field in the dc magnetic field perpendicular to the films and was strongly dependent on the film thickness. The dependences of the echo on the magnetic field and the film thickness are explained reasonably well by the modified surface spin pinning model. The values of the exchange constant, A, the magnetoelastic constant, B, and the sound velocity, v t obtained in the present experiments agree with those in other experiments.

Ultrasonic imaging with an electron beam scanned PVdF sensor

Abstract Reflection and transmission ultrasonic imaging can be achieved with high resolution and in real time when a monolithic piezoelectric sensor is scanned by an electron beam in vacuum. For many years, a half-wave resonant X-cut quartz crystal has provided the best compromise of resolution, sensitivity and vacuum compatibility. In this presentation the substantial improvement in image quality derived from the use of an electroactive PVdF sensor and its performance in high vacuum are discussed in terms of a detailed analysis of the way in which the acoustic wave enters the sensor plane and spreads by the multiple reflection process. Representative images obtained by reflection and transmission using both types of sensor are compared.

JOSA COMMUNICATIONS: Optical second-harmonic generation in transmission with long-range surface plasmons

We report the observation of enhanced optical second-harmonic generation in transmission that is due to excitation of the fundamental long-range surface-plasmon mode on both surfaces of a thin silver film bounded by a nonlinear X-cut quartz crystal and an index-matched liquid. The coherent harmonic generation that is observed leaving the polished side face of the nonlinear crystal is 3 orders of magnitude larger than that generated from a Z-cut quartz crystal in a Maker experiment.

Effects of domain structure on electrically excitable mechanical resonances in ferroelectric ceramics

Recently, I have announced the existence of electrically excitable mechanical resonances in piezoelectric and ferroelectric materials which are not accompanied by any detectable electrical disturbance. These observations are, of course, contrary to conventional understanding, and they are valid for X-cut quartz, Z-cut LiNbO3, slim loop ferroelectrics, PZT65/35, PLZT7/65/35,BaTiO3 ceramic, Clevite PZT8 and Channel 5500 ceramic, including virgin and thermally depoled specimens of ferroelectric ceramics. In this paper, the effects of domain structure on the existence of the mechanical resonances in the ferroelectric ceramic PZT65/35 are examined. It is shown that domain structure affects not only the number of these resonances but also their amplitudes. These observations are suggestive of the notion that the existence of these mechanical resonances may be due in part to the coupling of the driving electric field to the unit cell dipoles of the domains.

Orientation effects in chemical etching of quartz plates

The development of etch patterns of z-, y- and x-cut quartz plate is studied as a function of the specimen orientation. Plates of different cuts exhibit typical etch patterns satisfying either digonal or trigonal symmetry of α-quartz crystal. The changes of surface profilometry traces with depth of etch are also found to depend mainly on orientation dependence. The experimental data can be interpreted satisfactorily and consistently in terms of the structural reaction mechanism proposed by Ernsberger and in terms of the stability criterion. Some progress in the prediction of changes of etch figures with prolonged dissolution can thus be made by using some of the information reported in this paper.

Studies of the spectral and spatial characteristics of shock-induced luminescence from x-cut quartz

Spatial and spectral studies of shock-induced luminescence from x-cut crystalline quartz as a function of stress level revealed the following information: Crystalline x-cut quartz has a threshold for emission near the dynamic yield point (about 6 GPa); the spatial distribution of the luminescence from x-cut quartz changes from an intersecting linear emission pattern to a uniform emission pattern as the stress level increases from 6 to 8 GPa; spectra from x-cut quartz are band-like rather than blackbody; crystalline x-cut quartz has emission peaks near 400 and 600 nm; a change in the 400-nm emission with time can be correlated to wave interaction times. A discussion of the luminous emission in terms of yielding and other physical mechanisms is given.

Anomalous piezoelectric current pulses from impact-loaded lithium niobate

The present work reports study of impact-generated piezoelectric current pulses which deviate from elastic dielectric behavior. The anomalous current pulses are similar in character to those observed in prior work on X-cut quartz but differ significantly in detail.

Dielectric relaxation in insulators slightly damaged by stress pulses

The relationship between incipient stress-pulse-induced damage and the electrical response of a piezoelectric, ferroelectric, or electrically biased dielectric is examined. The model assumes the presence of isolated inclusions of damaged material which are conducting and which may grow. Virgin insulating material surrounds the inclusion . Sillars’ model of an inhomogeneous dielectric is invoked to yield parameters of an electrically equivalent, relaxing dielectric. These parameters are used to generate the electrical response caused by propagating stress pulses. Qualitative agreement with current histories obtained from experiments on X-cut quartz is obtained, quantitative results await further experimentation.

High-Temperature Measurements of Q-Factor in Rotated X-Cut Quartz Resonators

The Q-factors of piezoelectric resonators fabricated from natural and synthetic quartz with a 34° rotated X-cut orientation have been measured at temperatures up to 325°C. The synthetic material, which was purified by electrolysis, retains a high enough Q to be suitable for high-temperature pressure-transducer applications, whereas the natural quartz is excessively lossy above ~200°C application. The present results are compared to results obtained previously at AT-cut resonators.

Dynamic pressure-shear loading of materials using anisotropic crystals

An experimental technique is described which uses anisotropic crystals to generate dynamic pressure-shear loading in materials. The coupled longitudinal and shear motion generated upon planar impact of the anisotropic crystal can be transmitted into a specimen bonded to the rear surface of the crystal, and monitored using velocity interferometer techniques. Test results using y-cut quartz generators and x-cut quartz and y-cut quartz samples indicate that shear stresses up to 0.35 GPa can be transmitted across epoxy-bonded interfaces. The technique has been successfully used to detect a 0.2 GPa shear wave in 6061-T6 aluminum at 0.7 GPa longitudinal stress. The shear wave velocity profiles have an accuracy of ±12%. The use of longer delay legs in the interferometer is suggested to improve the accuracy. Results obtained in this investigation are compared with numerical solutions obtained using the finite-difference wave propagation code TOODY.

Measurement of the intensity distribution of laser radiation using Bragg diffraction of light

The necessary, estimates were obtained and it was demonstrated experimentally that the Bragg diffraction of light by ultrasonic waves in air may be used to measure the intensity distribution of laser radiation. A transducer utilizing an X-cut quartz crystal was developed to implement this technique. Measurements were made of the angular distribution of the ultrasonic field and its divergence was determined as 4×10–3 rad at 0.9 MHz. In order to confirm this possibility, measurements were made of the laser radiation distribution at λ = 0.6328 μ in the incident and Bragg-diffracted radiation.

A velocity interferometer technique to determine shear-wave particle velocity in shock-loaded solids

An optical technique is described which uses velocity interferometers to determine the large particle velocity changes associated with plane shear-wave propagation. In this technique two velocity interferometers are used to monitor different diffracted laser beams from a surface which undergoes both longitudinal and shear motion. Fringes produced in the interferometer are proportional to a linear combination of both the longitudinal and shear components of the free-surface velocity. The technique has been used successfully to monitor the free-surface velocity of a Y-cut quartz specimen impacted by an X-cut quartz plate. Although the present shear-wave velocity profiles are limited to an accuracy of ±10%, the accuracy can be easily increased by an order of magnitude by using longer delay legs and larger diffraction angles.

Ultrasonic Generation by Ferromagnetic Resonance in Evaporated Ni–Fe Alloy Films. I

A study of the generation of ultrasonics by ferromagnetic resonance in a 85% Ni–Fe alloy film evaporated onto an X-cut quartz single crystal is described. Two transverse shear waves are observed: i.e. fast and slow shear waves. The angular dependence of the ultrasonic power measured along the direction of the d.c. field for both shear waves has been explained reasonably well by taking into account the magnetoelastic effect and also the polarization effect of ultrasonics.

High frequency ultrasonic relaxations in smoky quartz

Pulse-echo ultrahigh frequency ultrasonic measurements in gamma irradiated natural brazilian X-cut quartz crystals reveal the existence of Debye relaxation peaks at low (18 K) and high (155 and 255 K) temperatures which can be attributed to transitions of the hole trapped at the oxygen ion nearest to the substitutional aluminum impurities. The observed activation energies are in agreement with previous anelastic and dielectric loss measurements but the relaxation times are found to be respectively one to two, and five orders of magnitude smaller for the high and low temperatures peaks. The low-temperature peak shows an apparent radiation annealing for gamma doses in excess of one megarad attributed to the closing of tunnelling transitions of the hole from low-lying intermediate energy levels due to electrostatic shifts of the asymmetry of the double-well potential by ionized defects. Uncoupling of the sound waves to the split ground state levels of the hole may be due to the anisotropy of the deformation potential constant.

A note on the behavior of 〈111〉 single crystals of β-BaF2 under shock compression at room temperature

In the present paper a physical explanation for the ’’peculiar’’ stress profiles as observed in the direct-impact experiments on 〈111〉 single crystals of β-BaF2 on x-cut quartz gauges by Dandekar and Duvall is provided. The model implies that in some cases, such as in β-BaF2, surface properties of the material make a significant contribution to the nature of the shock-wave profile.

Uniaxial Magnetic Anisotropy in Evaporated Films Caused by the Interaction with Substrate

A contribution to the magnetic anisotropy of evaporated films by an anisotropic mechanical stress caused by the substrate has been examined. Ni, Co, 85%Ni–Fe alloy with negative magnetostriction and 54%Fe–Co alloy with positive magnetostriction are evaporated onto X-and Z-cut quartz, and glass substrates. An anomalously large uniaxial magnetic anisotropy of 104∼105 ergs/cc compared to the induced anisotropy by magnetic annealing was found in all films deposited onto X-cut quartz substrates, while no anisotropy was found for the films deposited onto Z-cut quartz and glass. The direction of the easy axis and the value of the anisotropy are explained with the magneto-elastic coupling effect caused by the difference between the isotropic thermal expansion of films and the anisotropic expansion of the X-cut quartz substrate.

Brillouin spectroscopy of induced phonons in x-cut quartz

Abstract Triplepass Brillouin spectroscopy was used to detect longitudinal bulk waves generated at a y, z-surface of x-cut quartz. A comparison with Brillouin scattering by thermal phonons shows that Brillouin scattering by induced phonons admit sound attenuation measurements in a dynamic range of almost 80 dB at room temperature. It is also shown that our experimental results agree very well with results obtained at lower frequencies by pulse-echo measurements.

Effect of water and paint coatings on the magnitude of laser-generated shocks

The radiation from Q-switched neodymium-glass lasers was used to generate high amplitude stress waves in thin metal targets. The experiments were conducted in air at ambient conditions and pressure measurements were made with commercially available X-cut quartz crystals. Peak pressures exceeding 2 GPa were obtained by use of water and paint coatings.