Field-heated, field-cooled, and zero-field-heated static permittivity of the deuteron glass Rb1−x(ND4)xD2AsO4

Abstract

Dielectric permittivity and remanent polarization measurements have been performed in deuterated rubidium ammonium dihydrogen arsenate with x=0.28. Upon cooling the crystal, there is only the ‘‘transition’’ to the deuteron glass state. Static permittivity measurements were carried out along the a tetragonal axis at two different heating and cooling rates. Applying an external dc electric field along the a axis creates a bias which forces the acid deuteron in the O-D...O bond to lie at one end as opposed to the other as the temperature is lowered. This gives rise to a static permittivity (≊polarization and/or field) which freezes in below the glass ‘‘transition’’ temperature Tg. On switching the external electric field off, a remanent polarization is observed which vanishes above Tg as the ‘‘frozen’’ deuterons acquire more and more energy to overcome the random potential barriers. A theoretical fit with one adjustable parameter is seen to be in good agreement with the experimental results.