Dielectric and Raman investigations on M₂(SO₄). Te(OH)₆ (m =k, Rb and Cs)

Abstract

Dielectric and Raman investigations in the temperature and frequency ranges 300–550K and 10² – 10⁴Hz respectively show that M₂(SO₄). Te(OH)₆ with (M = K, Rb and Cs) materials present three phase transition. The first transition observed at 480, 440 and 460K respectively for M = K, Rb and Cs and should be probably of order-disorder type. The second one was observed only for Rb₂(SO₄). Te(OH)₆ and Cs₂(SO₄). Te(OH)₆ respectively at 510 and 495K. The third peak observed at 490, 520 and 510K for M = K, Rb and Cs respectively can be attributed to a ferroelectric-paraelectric phase transition.