Structure and magnetostrictive properties of Tb_(0.2)Pr_(0.8)(Fe_(0.4)Co_(0.6))_(1.9)B_x alloys

摘要

Crystal structure and magnetostrictive properties of Tb_(0.2)Pr_(0.8)(Fe_(0.4)Co_(0.6))_(1.9)B_x alloys have been investigated by means of x-ray diffraction and a standard strain technique. The matrix of Tb_(0.2)Pr_(0.8)(Fe_(0.4)Co_(0.6))_(1.9) alloy consists of (Tb,Pr)(Fe,Co)_2 phase with a cubic MgCu_2-type structure and some amount of (Tb,Pr)(Fe,Co)_3 phase with a PuNi_3-type structure. The introduction of boron effectively restrains the emergence of the iron-rich phase, which can occupy either the substitutional or interstitial site in this alloy system. The single Laves phase can be obtained for the high Pr-content Tb_(0.2)Pr_(0.8)(Fe_(0.4)Co_(0.6))_(1.9)B_x alloys with 0.05＜ x ≤0.15, which have improved magnetostrictive properties as compared to the boron free material.