Acoustic, opto-acoustic, and thermal properties investigated around the phase transitions of NaCN and Na(CN<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mi mathvariant="italic">x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Cl</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mm

Krüger, Jan; Jiménez, Rafael Madueño; Bohn, K.-P.; Petersson, J.; Albers, J.; Klöpperpieper, A.; Sauerland, E.; Müser, H. E.

doi:10.1103/physrevb.42.8537

Cited by 22 publications

(3 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5, it can be seen that ν decreases with k m as expected from Eq. (18). For each sample, a global leastsquares fit was done on the corresponding longitudinal and transverse mode data.…”

Section: Resultsmentioning

confidence: 99%

Probing near-normally propagating bulk acoustic waves using pseudo-reflection geometry Brillouin spectroscopy

Parsons

Andrews

2012

AIP Advances

View full text Add to dashboard Cite

Pseudo-reflection geometry Brillouin spectroscopy can be used to probe acoustic wave dispersion approximately along the surface normal of a material system while avoiding the difficulties associated with specularly reflected light encountered in an ideal reflection configuration. As an example of its application, we show analytically that it can be used to determine both the refractive index and bulk acoustic mode velocities of optically-isotropic non-metallic materials and confirm the utility of the approach via a series of experiments on fused quartz, gallium phosphide, water, and porous silicon films.

show abstract

“…5, it can be seen that ν decreases with k m as expected from Eq. (18). For each sample, a global leastsquares fit was done on the corresponding longitudinal and transverse mode data.…”

Section: Resultsmentioning

confidence: 99%

Probing near-normally propagating bulk acoustic waves using pseudo-reflection geometry Brillouin spectroscopy

Parsons

Andrews

2012

AIP Advances

View full text Add to dashboard Cite

show abstract

“…This behavior of c 44 is very similar to the one observed in systems where the TR coupling plays the main role in the transition. 14,32 The magnetic susceptibility, i.e., the tendency for the system to locally remove the groundstate degeneracy is translated onto the lattice as an orientational disorder of the GeO͑2͒ 2 units which, through the TR coupling, induces the observed anomalies in both the acoustic constants and in the thermal expansion coefficients. The measured crossing of c 22 and c 44 at around 60 K could be the result of the postulated structural evolution and distortion freezing prior the spin-Peierls transition.…”

Section: Resultsmentioning

confidence: 99%

Anomalous hypersonic behavior ofCuGeO3prior to the spin-Peierls transition

et al. 1998

View full text Add to dashboard Cite

The temperature dependence of the longitudinal elastic constants c 22 , c 33 , and of the transverse elastic constant c 44 , as obtained by Brillouin spectroscopy, reveals an unexpected elastic behavior in CuGeO 3 prior to the spin-Peierls magnetic transition (T SP Ϸ14.1 K). At room temperature c 33 ӷc 44 Ͼc 22 . Below about 50 K a steep increase in the values of the longitudinal elastic constants leads to a crossover of the values of c 22 and c 44 with c 22 Ͼc 44 . The existence of translation-rotation coupling in CuGeO 3 could account for the elastic behavior above T SP . The anisotropy of the magnetoelastic coupling at the spin-Peierls transition temperature is reflected in the different temperature behavior

show abstract

“…It has been shown previously (e.g., [15,16]) that the acoustic wavelength L 90A does not depend on the refractive index of the sample and therefore gives the relationship L 90A l 0 ͞ p 2. In a macroscopically isotropic sample the use of both scattering geometries yields the optoacoustic dispersion coefficient D [17,18]. In the acoustic dispersion-free case, D f 180 ͑͞ f 90A p 2 ͒ gives the refractive index n [17] at the laser wavelength l 0 ( f 90 and f 180 are the phonon frequencies measured in the 90A-and 180-scattering geometry, respectively).…”

mentioning

confidence: 99%

Evidence of an Elastic Instability between the Amorphous and the Microcrystalline State of Ca-modified Lead Titanate as revealed by Brillouin Spectroscopy

et al. 1997

Self Cite

View full text Add to dashboard Cite

Brillouin spectroscopy was used to probe the hypersonic properties of Ca-modified lead titanate between the pure amorphous and the coarse grained state. The samples were thin films rf sputtered onto (100)-silicon wafer at ambient temperature, followed by an annealing process in the range from 673 to 873 K. An elastic instability of the longitudinally polarized sound mode suggests the existence of a discontinuous structural transformation from the amorphous to the nanostructured state. [S0031-9007(97)02610-0] PACS numbers: 81.05. Ys, 68.35.Rh, 68.60.Bs, 78.35. + c Against the background of an increasing interest in nanostructured materials (nsM) the physical properties of the intermediate metastable structures between the pure amorphous and the microcrystalline states require special attention. One possible way to realize such intermediate states is to produce sputtered amorphous (dielectric) films and to anneal these films successively in an appropriate way. It is likely that the annealing-induced transformation from the initial amorphous state to the final coarse grained state may pass through one or more so-called metastable nanocrystallized states (e.g. [1][2][3][4][5]). It is a matter of current physical interest (i) whether these intermediate nanostructured states (nsS) can be fixed, (ii) how the transformation from the amorphous to the microcrystalline states takes place, and (iii) what are the properties of these intermediate states. Although the amorphous state as well as the nsS are metastable, the possibility of a structural phase transformation between the crystalline and the amorphous states has been proposed in the literature [1,5]. Based on free-energy simulations, Wang et al. [6], only recently, have predicted a phase transition from the nanocrystalline to the glassy state. A hint for the existence of such a transition may be drawn from the work of Rehn et al. [1]. These authors have reported an elastic shear instability for ion damaged Zr 3 Al.It is well established now that the evolution of the nsS is accompanied by an anomalous behavior in the elastic properties when compared to the amorphous and the microcrystalline reference states [2,4,7,8]. Experimental and theoretical results indicate a significant influence in the size of nanoparticles on the elastic properties of the consolidated nsM (e.g., [2,4,[9][10][11][12][13]). In turn, the elastic properties are expected to reflect the predicted transition from the amorphous to the nsS. The aim of the current paper is to show evidences for such a transformation in rf-sputtered films of Ca-modified lead-titanate ͑Pb 0.76 Ca 0.24 ͒TiO 3 (PTC) at a critical annealing temperature ͑T ca ഠ 823 K͒. As a sensitive probe we used the lon-gitudinally polarized acoustic phonon mode as detected by high resolution Brillouin spectroscopy (BS).PTC is -in the single or coarse grained polycrystalline state-a ferroelectric perovskite with a phase transition from the paraelectric to the ferroelectric state at T c ഠ 530 K [14]. At room temperature, the material is t...

show abstract

Acoustic, opto-acoustic, and thermal properties investigated around the phase transitions of NaCN and Na(CN)xCl1

Cited by 22 publications

References 29 publications

Probing near-normally propagating bulk acoustic waves using pseudo-reflection geometry Brillouin spectroscopy

Probing near-normally propagating bulk acoustic waves using pseudo-reflection geometry Brillouin spectroscopy

Anomalous hypersonic behavior ofCuGeO3prior to the spin-Peierls transition

Evidence of an Elastic Instability between the Amorphous and the Microcrystalline State of Ca-modified Lead Titanate as revealed by Brillouin Spectroscopy

Contact Info

Product

Resources

About