MODEL CALCULATION OF THE CRYSTAL-FIELD MAGNETOSTRICTION AND ITS TEMPERATURE-DEPENDENCE IN THE ITINERANT UNIAXIAL FERROMAGNET Y2FE17

The observed crystal-field magnetostriction and its complex temperature dependence have been calculated for the itinerant iron-rich uniaxial ferromagnet Y2Fe17, using a simple, although highly efficient, type of rigid-band Stoner model. We have evaluated the irreducible magnetostriction modes epsilon(alpha,1) and epsilon(alpha,2), which represent the volume and c-axis pure tetragonal strains, respectively, as well as their temperature dependencies. Good agreement with the available experimental results has been attained. As a result, values of the corresponding microscopic magnetoelastic coupling coefficients, M12alpha and M22alpha, have been obtained. Those values are very large (around -10(3) K/Fe atom), as expected for an intermetallic compound with a 3d shell transition element.