Ag. Gavrilyuk et al., Effect of high pressures on exchange and hyperfine interactions in rare-earth orthoferrites, J EXP TH PH, 90(2), 2000, pp. 330-340
The effect of high pressures P on the Neel temperature T-N , the crystal la
ttice parameters, and the magnitude of the hyperfine magnetic field H-Sn at
a nucleus of a diamagnetic tin atom was studied in pure and tin-doped orth
oferrites RFeO3 (R = Nd, Lu). The dependence of these quantities on the geo
metry of the exchange bonds, specifically, the angle and length of the chem
ical bond Fe-O-Fe(Sn), was analyzed. It was established that under pressure
the angular contribution decreases and the radial contribution increases T
-N and H-Sn, the radial contribution being greater than the angular contrib
ution in absolute magnitude. Numerical estimates were obtained for the angu
lar and radial contributions to T-N and H-Sn. In lutecium orthoferrite, at
P > 30 GPa anomalies indicating a possible phase transition were observed i
n the behavior of the lattice parameters and the value of H-Sn. (C) 2000 MA
IK "Nauka/Interperiodica".