Size-driven ferroelectric effects in TGS induced by high hydrostatic pressure

The parameters PS, Ec, ε and TC of TGS monocrystals were investigated under high hydrostatic pressure of up to 2.5 GPa. It has been found that above a critical pressure pc of about ≈ 1.8 GPa the derivative dTCdp starts to be negative and ferroelectricity disappears at about 2.5 GPa. The analysis of the reciprocal permittivity ε− 1 reveals that after the avalanche-type structure destruction the TGS samples show a relaxor-like behavior. It is suggested that polar nano-regions formed under high critical pressure mutually interact, in contrast to the case of a superparamagnetic. It is concluded that the TGS phase above 2.5 GPa may be referred to as a superparaelectric limit.