![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
This paper presents the results of the investigation of dielectric dispersion and ultrasonic velocity in the ferroelectric (CH3)2NH2Al(SO4)2 · 6H2O crystal. The crystal shows a critical slowing down process of polarization with an extremely long relaxation time of the dipole system (τ = 1.6 · 10−7s at the phase transition point). The dielectric response over the frequency range up to 56 GHz in the paraelectric phase can be well described in terms of a monodispersive Debye-type formula. The activation energy of dipoles in the paraelectric phase is 0.11 eV = 8.5 kTc . The results show that the proper ferroelectric phase transition is nearly critical and of the order-disorder type.
