Magnetomechanical coupling in rare-earth-iron alloys

The magnetomechanical coupling factor k33 and Young's modulus E have been measured in Smsub(0.88)Dysub(0.12)Fe2, Smsub(0.7)Hosub(0.3)Fe2 and Smsub(0.82)Dysub(0.09) Hosub(0.09)Fe2. The maximum value of k33 was found to be 0.55 in Smsub(0.88)Dysub(0.09)Fe2, which is about the same as previously found in Tbsub(0.27)Dysub(0.73)Fe2. The maximum value for k33 in Smsub(0.7)Hosub(0.3)Fe2 was about 0.35, and 0.48 in Smsub(0.82)Hosub(0.3)Dysub(0.09)Fe2. Young's modulus at constant field (Esub(H)) is lowest Smsub(0.7) Hosub(0.3)Fe2. The low-field value of Esub(H) in Smsub(0.88) Dysub(0.12)Fe2 is about 70% that found in Tbsub(0.27)Dysub(0.73) Fe2. Smsub(0.82)Dysub(0.09)Hosub(0.09Fe2 has the largest value of Esub(H) of the Sm-based alloys. The value of k33 and Esub(H) was found more dependent on magnetic drive in the Sm-based alloys than in the Tb-based alloys. It is also found that the magnetomechanical coupling varies smoothly from fields well below saturation to fields above saturation. This shows that intrinsic magnon-phonon coupling is probably contributing substantially to the values of k33 and the Δ E effect at low fields. Sample preparation is discussed. (author)