O-17 NQR STUDY OF GLASS ORDER IN RB-0.5(NH4)(0.5)H2PO4

The shape of the 5/2-3/2 transition line in the O-17 NQR spectrum of t he proton pseudo-spin-glass Rb-0.5(NH4)(0.5)H2PO4 was measured as a fu nction of temperature by a highly sensitive H-1-O-17 nuclear-quadrupol e double-resonance technique. The results clearly show a temperature-d ependent distribution of the local polarization of the O-H ... O hydro gen bonds characteristic for glasses. The Edwards-Anderson order. para meter q(EA), i.e., the second moment of the local polarization distrib ution, is determined from the second moment of the O-17 NQR line. The variance Delta of the Gaussian distribution of random fields is determ ined from the temperature dependence of q(EA) as being Delta = [k(B)(1 00 K)](2).