INVESTIGATION OF THE EFFECT OF UNIAXIAL PRESSURE ON ANTIFERROMAGNETIC-RESONANCE IN KFE11OL7 CRYSTALS

The deformation dependence of the resonance field in KFe11O17 single c rystals was investigated by the AFMR method The measurements were perf ormed at T = 77 K and nu = 47.52 GHz for two orientations of the exter nal pressure, The experimental data are discussed in terms of a model of a very simple easy-place antiferromagnet taking account of the elas tic and magnetoelastic contributions to the thermodynamic potential Th e magnetostriction, magnetoelastic, and elastic contants are calculate d and the results are lambda = 1.94 x 10(-5), B-1 = 2.75 X 10(8) erg/c m(3), and C-11-C-12 = 1.42 X 10(13) erg/cm(3), respectively. The value s of these constants imply that the origin of the initial gap in the A FMR spectrum is not of magnetoelastic origin. (C) 1998 American Instit ute of Physics. [S1063-7834(98)02403-4].