Phase transitions in PbZr0.72Sn0.28O3 single crystals studied by Raman spectroscopy

Two-dimensional (2D) materials driven by their unique electronic and optoelectronic properties have opened up possibilities for their various applications. The large and high-quality single crystals are essential to fabricate high-performance 2D devices for practical applications. Herein, IV-V 2D GeP single crystals with high-quality and large size of 20 × 15 × 5 mm3 were successfully grown by the Bi flux growth method. The crystalline quality of GeP was confirmed by high-resolution X-ray diffraction (HRXRD), Laue diffraction, electron probe microanalysis (EPMA) and Raman spectroscopy. Additionally, intrinsic anisotropic optical properties were investigated by angle-resolved polarized Raman spectroscopy (ARPRS) and transmission spectra in detail. Furthermore, we fabricated high-performance photodetectors based on GeP, presenting a relatively large photocurrent over 3 mA. More generally, our results will significantly contribute the GeP crystal to the wide optoelectronic applications.

Download Full-text

Magnetic phase transitions in Eu( Co1−xNix)2−yAs2 single crystals

Physical Review Materials ◽

10.1103/physrevmaterials.4.084407 ◽

2020 ◽

Vol 4 (8) ◽

Cited By ~ 1

Author(s):

N. S. Sangeetha ◽

Santanu Pakhira ◽

D. H. Ryan ◽

V. Smetana ◽

A.-V. Mudring ◽

...

Keyword(s):

Phase Transitions ◽

Single Crystals ◽

Magnetic Phase ◽

Magnetic Phase Transitions

Download Full-text

On the nature of the phase transitions of aluminosilicate perrhenate sodalite

Zeitschrift für Kristallographie - Crystalline Materials ◽

10.1515/zkri-2020-0027 ◽

2020 ◽

Vol 235 (6-7) ◽

pp. 213-223

Author(s):

Hilke Petersen ◽

Lars Robben ◽

Thorsten M. Gesing

Keyword(s):

Raman Spectroscopy ◽

Phase Transitions ◽

Decomposition Temperature ◽

Second Phase ◽

Structure Property ◽

X Ray Diffraction ◽

Temperature Dependent ◽

Two Phase ◽

Structure Property Relationships ◽

Heat Capacity Measurements

AbstractThe temperature-dependent structure-property relationships of the aluminosilicate perrhenate sodalite |Na8(ReO4)2|[AlSiO4]6 (ReO4-SOD) were analysed via powder X-ray diffraction (PXRD), Raman spectroscopy and heat capacity measurements. ReO4-SOD shows two phase transitions in the investigated temperature range (13 K < T < 1480 K). The first one at 218.6(1) K is correlated to the transition of dynamically ordered $P\overline{4}3n$ (> 218.6(1 K) to a statically disordered (<218.6(1) K) SOD template in $P\overline{4}3n$. The loss of the dynamics of the template anion during cooling causes an increase of disorder, indicated by an unusual intensity decrease of the 011-reflection and an increase of the Re-O2 bond length with decreasing temperature. Additionally, Raman spectroscopy shows a distortion of the ReO4 anion. Upon heating the thermal expansion of the sodalite cage originated in the tilt-mechanism causes the second phase transition at 442(1) K resulting in a symmetry-increase from $P\overline{4}3n$ to $Pm\overline{3}n$, the structure with the sodalites full framework expansion. Noteworthy is the high decomposition temperature of 1320(10) K.

Download Full-text