Effect of Dy doping on magnetostrictive and mechanical properties of Fe83Ga17 alloy

Abstract

M agnetostriction is generally considered as the change in dimension of materials under an applied external magnetic field. Magnetostrictive materials have attracted widespread attention due to their utilization in actuators, sensors, transducers, microelectromechanical systems and energy harvesting [1,2] . Among various magnetostrictive materials, the Tb-Dy-Fe alloys (known as Terfenol-D) and Fe-Ga alloys (known as Galfenol) are the two most promising materials. Compared to Terfenol-D, Fe-Ga alloys exhibit good combination advantages: (i) low saturation magnetic field (~100 Oe); (ii) moderate magnetostriction (~400 ppm); (iii) good mechanical properties; (iv) low cost; (v) high Curie temperature (T c >650 °C ) [3][4][5][6][7] . Therefore, since 2000, many studies on microstructure, magnetostrictive and mechanical properties of Fe-Ga alloys have been carried out.Fe-Ga single crystal alloys exhibit good robustness,

Influence of Dy substitution for Ga on the magnetic properties of arc-melted Fe-Ga alloys

“…The lower saturation magnetization that can be achieved in the x=0.25 alloy is due to the higher Ga atomic percentage that is present in the alloy. Because this alloy has a greater proportion of the nonmagnetic element Ga than other Dy doped alloys, the Fe-Fe interaction and Dy rich phases lead to the low saturation magnetization (Ms) [7,17]. The table insets in figures 4(a)-(e) confirm the increase in Dy content in the Fe-Ga alloys.…”

“…The increase in H C and Mr after adding Dy beyond (x=0.25) is also due to a large amount of phase formation enriched in Ga or Dy [33], as shown in SEM micrograph figure 3(a), where Ga atoms are present at larger grain boundaries. The minimal saturation magnetization ∼100 emu g −1 achieved at x=0.25 is a result of the Fe-Fe interactions and Dy-rich phase precipitation [17]. The greater proportion of the nonmagnetic element Ga is responsible for this alloy's lower Ms.…”

“…Similar to Tb-substituted Fe-Ga alloys, the magnetostriction of the Dy-substituted Fe 73 -Ga 27 alloys exhibits considerable improvements. After x=0.50, however, the number of Dy-rich precipitates has a negative effect on the magnetostrictive behaviour of Dy-substituted Fe-Ga alloys, resulting in a decrease in magnetostriction [17]. The formation of Ga and Dy pairs is responsible for the enhancement of magnetostriction and rare earth elements such as Dysprosium (Dy) and Terbium (Tb) possess strong magnetic anisotropy, which originates from spin-orbit coupling and increases the magnetostriction of Fe-Ga alloys [11].…”

“…Dysprosium (Dy) is another familiar rare earth element with a good extent of magnetocrystalline anisotropy. Tb and Dy both seem to have a closely packed hexagonal structure [16,17].…”

Temperature-Induced Phase Transitions of Fe-Ga Alloys for Sensors

“…The increased magnetostrictive properties of Fe-Ga (Galfenol) alloys makes it as a promising material for sensors (3,4), actuators, acoustic transducers, and energy harvesters (5)(6)(7)(8)(9). Fe-Ga alloys outperform other magnetostrictive materials (Terfenol -D) in terms of low stability, cost, hysteresis, and saturation (10)(11)(12)(13)(14)(15). The phase transformation with low-temperature diffusion-controlled in the Fe-Ga alloys allow to keep phases formed at non equilibrium high-temperature after crystallisation from the quenching or melting (16)(17)(18).…”