Magnetostriction of DyFe2 and HoFe2:: Validity of the single-ion model

Analysis of available experimental data on the temperature dependence of the tetragonal magnetostriction constant lambda (100) in DyFe2 and HoFe2 confirms validity of the single-ion model. The most important contributions to lambda (100) come from the second- and sixth-order terms, which are of the same order of magnitude. They also are similar in magnitude to the higher-order (n=4,6) terms in the trigonal magnetostriction constant lambda (111). It is therefore concluded that the origin of the extraordinarily large lambda (111) in RFe2 (where R is rare earth) is confined to the second-order, or quadrupole term in lambda (111). (C) 2001 American Institute of Physics.