Giant magnetostriction and narrow hysteresis over a broad temperature window in Tb_0.34Dy_0.66Fe_1.95V_0.05 alloy

Achieving large magnetostriction (λ_a) with narrow hysteresis and broad operating temperature range remains a critical challenge for Laves-phase RFe₂-based (R = rare earth) materials. Herein, an alloy of Tb_0.34Dy_0.66Fe_1.95V_0.05 is designed by optimizing the Tb/Dy ratio to regulate spin reorientation temperature and incorporating V to inhibit secondary phases. The targeted compound exhibits an expanded operating temperature span up to 215 K (2.15 times wider than Terfenol-D) with superior thermal stability (average temperature coefficient: 2.6 ppm/K for Tb_0.34Dy_0.66Fe_1.95V_0.05 vs. 5.6 ppm/K for Terfenol-D). Moreover, a room-temperature λ_a of 1310.75 ppm with ultralow hysteresis of ∼ 1.7 % is obtained under 20 kOe. Further, a giant magnetostriction of 1982.91 ppm is acquired due to a rhombohedral-tetragonal transition when the temperature drops to 150 K. This work provides an effective strategy for designing high-performance magnetostrictive materials.