Composition Dependence on Compressive Magnetostriction of Fe–Sm Binary Alloy Thin Films

Abstract

Influences of composition on magenetostriction of Fe-Sm alloy thin films prepared by D.C. magnetron sputtering process were investigated. Composition of formed film was ranged from 24 to 59 at%Sm. Negative, that is, compressive magnetostriction was observed of FeSm thin films. The magenetostriction of thin films was varied with composition rate of Fe-Sm alloy. The giant magnetostriction (GM) over 1000 ppm at 1200 kA/m was observed from 24 to 34 at%Sm for Fe-Sm amorphous film. The limited value of GM at 1200 kA/m was 1280 ppm of Fe-29.3 at%Sm alloy film.

The Success of Fabrication of Pure SmFe2 Phase Film with Outstanding Perpendicular Magnetic Anisotropy

“…Additionally, the magnetostrictive coefficient of the sample deposited at 550 • C and annealed at 700 • C for 30 min is higher than that of the sample deposited at 300 • C and annealed at 700 • C for 45 min, suggesting that higher temperature deposition and annealing lead to higher purity of the SmFe 2 phase. However, the maximum magnetostrictive coefficient achieved in the Sm-Fe films we prepared is −234 ppm, which is lower than the values reported in the literature [37,38]. This may be attributed to the high thickness of the Si substrate used for depositing the Sm-Fe films, which affects the magnitude of stress [39].…”

Role of magnetostrictive effect in magnetization dynamics of SmFe thin films

“…Usually, the maximum λ s of the amorphous SmFe thin films also occurs at x = 0.3-0.4, with a relatively lower value of about −200 to −1100 ppm than that of the SmFe 2 alloy, depending on the sample preparation conditions. [18][19][20] As we know, the Sm x Fe 1-x alloy film with the largest λ s will give rise to a dramatic shrink along the field direction due to the negative λ s . With fs laser pumping, the sudden change of angular momentum should be transferred from spins to the lattice of the SmFe film.…”

“…17) However, it cannot be ignored in the RE x Fe 1-x alloys with x in the range of 0.3-0.4, whose λ s was reported to be almost 2-3 orders of magnitude larger. [18][19][20][21] For instance, λ s ∼ 1900 ppm and 2000 ppm of TbFe 2 and SmFe 2 alloys, respectively. 21) The giant magnetostrictive effect of RE x Fe 1-x alloy is considered to originate from the strong spin-orbit coupling effect of 4f electrons.…”

“…by which all the Sm x Fe 1-x samples show amorphous phases, which are consistent with the results reported earlier. 19) The laser-induced ultrafast demagnetization process was measured by TR-MOKE in the longitudinal geometry, with an inplane saturation field of 5.0 kOe applied for all the samples. In contrast, the magnetization precession and damping behavior was obtained in a polar geometry at various magnetic fields at an angle of 71°with respect to the film normal.…”

“…As expected, it follows nearly the same variation trend of t 2 , reaching a maximum at the Sm content of x = 0.31-0.33, where the SmFe films own a quite large λ s . [18][19][20] According to the equation of we have roughly estimated the magnetostriction coefficient of the SmFe films. Assuming σ is 125 MPa for H = 10 kOe, 33) the magnitude of λ s is calculated to be about 249 ppm for x = 0.31, which is in good accordance with the reported data for the amorphous SmFe films.…”