Heat capacity in magnetic and electric fields near the ferroelectric transition in triglycine sulfate

Abstract

Specific-heat measurements are reported near the Curie temperature (TC =320 K) on triglycine sulfate. Measurements were made on crystals whose surfaces were either nongrounded or short circuited, and were carried out in magnetic fields up to 9 T and electric fields up to 220 Vcm. In nongrounded crystals the authors find that the shape of the specific-heat anomaly near TC is thermally broadened. However, the anomaly changes to the characteristic sharp λ shape expected for a continuous transition with the application of either a magnetic field or an electric field. In crystals whose surfaces were short circuited with gold, the characteristic λ shape appeared in the absence of an external field..