Al27 nucleus NMR in PrAlO3 trigonal and tetragonal phases

Parameters of Al27 NMR spectrum in two phases of praseodymium aluminate have been measured for the first time. At 300 K (trigonal symmetry of the crystal) parameters of quadrupole splitting are as follows: e2qQ/h=(0.46+-0.01)MHz, eta=0, at 77 K tetragonal symmetry -e2qQ/h=(0.38+-0.01)MHz, eta=0. Orientation of the spectrum axis in the first case corresponds to the direction [111] of pseudocubic cell, in the second one - to the direction [001]. It is shown that at the temperature of liquid nitrogen the spectrum lines undergo paramagnetic shift, caused by the effect of Pr3+ ions and qualitatively correlating with the data on magnetic susceptibility of PrAlO3 crystal