Optical Investigations of Phase Transitions in (NH_{4})_{2}SbF_{5} Crystal

• Authors: B. Andriyevsky , Z. Czapla , V. Stadnyk
• Languages of publication: EN

Abstracts

EN

Results of optical thickness and refractive indices measurements for (NH_{4})_{2}SbF_{5} crystal in the temperature range 100-310 K are presented. The measurements were done with interference method using He-Ne laser (λ = 632.8 nm). At T_{c1} = 292 K and T_{C2} = 168 K two continuous phase transitions with critical indices β_{1} = 0.38 and β_{2} ≤ 0.57 were observed. Ad­ditional anomaly of temperature changes of interference order with maximum at T_{c3} ≈ 132 K were found. This anomaly resembles a diffused transition. Temperature-averaged values of derivatives of refractive indices dn_{g} /dT = -3.3 × 10^{-5} K and dn_{m}/dT = -2.9 × 10^{-5} K^{-1} evidenced a decrease in optical anisotropy (birefringence) along the b-axis on heating run.

Keywords

EN

64.70.Kb; 78.20.Fm

Discipline

• 78.20.Fm: Birefringence

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 1995
• Volume: 87
• Issue: 3
• Pages: 611-617

Dates

published

1995-03

received

1994-03-29

(unknown)

1994-09-06

Contributors

author

B. Andriyevsky

• Lviv State I. Franko University, Kyryla and Mefodiya 8, 290005 Lviv, Ukraine

author

Z. Czapla

• Institute of Experimental Physics, University of Wrocław, Pl. M. Borna 9, 50-204 Wrocław, Poland

author

V. Stadnyk

• Lviv State I. Franko University, Kyryla and Mefodiya 8, 290005 Lviv, Ukraine

Identifiers

DOI

10.12693/APhysPolA.87.611