Sputter deposited Terfenol-D thin films for multiferroic applications

Abstract

In this paper, we study the sputter deposition and crystallization process to produce high quality Terfenol-D thin film (100 nm) with surface roughness below 1.5 nm. The Terfenol-D thin film was produced using DC magnetron sputtering technique with various sputtering parameters and two different crystallization methods, i.e. substrate heating and post-annealing. Several characterization techniques including WDS, XRD, TEM, AFM, SQUID and MOKE were used to determine the physical and magnetic properties of the Terfenol-D films. TEM studies reveal that the film deposited on the heated substrate has large grains grown along the film thickness producing undesirable surface roughness while the film crystallized by post-annealing method shows uniformly distributed small grains producing a smooth surface. The Terfenol-D film was also deposited onto (011) cut PMN-PT single crystal substrate. With the application of an electric field the film exhibited a 1553 Oe change in coercivity with an estimated saturation magnetostriction of λs = 910 x 10−6.

Magnetostrictive Performance of Electrodeposited TbxDy(1−x)Fey Thin Film with Microcantilever Structures

“…However, the importance of the thin-film technology for those materials have gained for realizing miniaturized smart actuators and devices. Many methods have been reported for thin-film preparation, including pulsed laser deposition [7], sputtering [10,11,[19][20][21][22][23][24][25][26][27][28], and electrochemical deposition [5,6,9,29]. For the film deposition of Terfenol-D, the sputtering method has been reported because of the simple approach, high film uniformity, and low roughness.…”

“…However, the substrate must be heated at a temperature higher than 400 • C for crystallization, because the sputter-deposited Terfenol-D films are amorphous state at low temperatures, which show a low magnetostrictive performance [23][24][25]. Those sputtered films exhibit a magnetostriction coefficient approximately 1/3 (540 ppm) of the bulk value without annealing and 2/3 (920 ppm) of the bulk value with annealing at 450 • C [19][20][21]. Electrochemical deposition has advantages for simplicity, low cost, and compatibility with batch fabrication, etc., and some of the researches have been reported regarding magnetostrictive thin films including Galfenol [5,6], CoFe [9], and TbFe 2 [29].…”

Bi-directional coupling in strain-mediated multiferroic heterostructures with magnetic domains and domain wall motion

“…Manipulation of magnetization via the strain-based approach has already been demonstrated experimentally in Ni 10 , 19 – 22 , CoFeB 23 , FeGa 24 , Fe and CoFe 9 on piezoelectric substrates. Increasing interest in highly magnetoelastic materials, such as Terfenol-D (Tb x Dy 1−x Fe 2 , x = 0.3) with magnetostriction saturation = 25 , creates the need for thorough understanding of the magnetization behavior inside these materials owing to their potential for enhanced strain-mediated DW rotation 26 – 29 . As a side note, maximizing magnetostriction is often a desirable pursuit, although there are cases where there are nuanced tradeoffs and maximum magnetostriction is not necessarily a standalone objective.…”

Determination of the exchange constant ofTb0.3Dy0.7Fe2by broadband ferromagnetic resonance spectroscopy

“…31–34 A parametric study of sputtering deposition parameters and their resultant static magnetization characteristics was recently performed by Mohanchandra et al . 35 However, as of this letter, the dynamic properties of thin film Terfenol-D needed for accurate understanding and predictive modeling remain unknown.…”

“…Using dc magnetron sputtering and a post-growth annealing process described elsewhere, we grew the following trilayer on thermally oxidized Si(100): Ta (10 nm)/Terfenol-D (80 nm)/Ta (10 nm). 35 The dynamical properties were studied using broadband ferromagnetic resonance spectroscopy, schematically depicted in Fig. 1.…”