Crystal Structure, Electric Polarization and Heat Capacity Measurements on Small R-Ion Multiferroic Hexagonal RMnO$_{3}$

Crystal structure, electric polarization and heat capacity measurements on the hexagonal multiferroic RMnO$_{3}$ reveal that small R ion (Lu and lower cation size) systems are ferroelectric and possess the same space-group as YMnO$_{3}$. Combined local and long range structural measurements were conducted by XAFS, PDF and single crystal and powder XRD methods. The influence of the Mn-O and R-O distribution on the electric polarization is discussed. Point charge estimates of the electrical polarization are given for comparison with the YMnO$_{3}$ system. This work is supported by DOE Grant DE-FG02-07ER46402.