Spin Orientation and Magnetostriction of Tb1−xDyxFe2 from First Principles

Model of the local td environment of the re atom in the cubic laves phase

Dr Christopher Patrick, in collaboration with the University of Warwick, derived the first principle value of Tb1-xDyxFe2 for room-temperature applications by calculating the easy magnetization direction and magnetostriction as a function of composition and temperature.


Crystal-field coefficients were used, which were obtained from within density-functional theory to construct phenomenological anistropy and magnetoelastic constants.  The temperature dependence of these constants was obtained from disordered-local-moment calculations of the rare-earth magnetic order parameter.


The researchers' calculations found the critical Dy concentration required to switch the magnetization direction at room temperature to be xc = 0.78, with magnetostrictions λ111 = 2700 and λ100 = −430 ppm, close to the Terfenol-D values.


The full paper is available to read in volume 14 of Physical Review Applied.