ENDOR INVESTIGATION OF THE POLAR STRUCTURE OF TRIS-SARCOSINE CALCIUM-CHLORIDE

H-1 and C-13 ENDOR investigations on Mn-doped tris-sarcosine calcium chloride (TSCC) and tris-sarcosine calcium bromide (TSCB) at 4.2 K reveal the polar structure of the calcium-(sarcosine)6 complex in the ferroelectric phase of TSCC. The sarcosine molecules of type I do not change their position in the ferroelectric phase and give no contribution to the spontaneous polarization. The molecules of type II undergo an opposite tilt of about 3-degrees in the (100) plane at 4.2 K. This tilting angle is temperature dependent and responsible for the polar structure of TSCC below T(c).