Magnetoelastic coupling induced magnetic anisotropy in Co₂(Fe/Mn)Si thin films

Abstract

The influence of epitaxial strain on uniaxial magnetic anisotropy of Co 2 FeSi (CFS) and Co 2 MnSi (CMS) Heusler alloy thin films grown on (001) SrTiO 3 (STO) and MgO is reported. The in-plane biaxial strain is susceptible to tune by varying the thickness of the films on STO, while on MgO the films show in-plane easy axis for magnetization ( − → M ) irrespective of their thickness. A variational analysis of magnetic free energy functional within the Stoner-Wohlfarth coherent rotation model with out-of-plane uniaxial anisotropy for the films on STO showed the presence of magnetoelastic anisotropy with magnetostriction constant ≈ (12.22±0.07)×10 −6 and (2.02±0.06)×10 −6 , in addition to intrinsic magnetocrystalline anisotropy ≈ -1.72×10 6 erg/cm 3 and -3.94×10 6 erg/cm 3 for CFS and CMS, respectively. The single-domain phase diagram reveals a gradual transition from in-plane to out-of-plane orientation of magnetization with the decreasing film thickness. A maximum canting angle of 41.5 • with respect to film plane is predicted for the magnetization of the thinnest (12 nm) CFS film on STO. The distinct behaviour of − → M in the films with lower thickness on STO is attributed to strain-induced tetragonal distortion.

Magnetoelastic interactions and magnetic damping in Co2Fe0.4Mn0.6Si and Co2FeGa0.5Ge0.5 Heusler alloys thin films for spintronic applications

“…Magnetoelastic interactions in the studied samples are relatively weak (part of the data was previously published 80 ). Experimentally determined magnetoelastic constants B 11 have values in the range of − (6–30) × 10 6 erg/cm 3 (see Table 1 ), which are close to the values reported for Co 2 YSi (with Y = Fe or Mn) 70 and for Co 2 FeAl 66 . Figure 3 illustrates the magnetoelastic constants dependence on the film thickness.…”

“…The effects connected with piezoelectric strain were studied in Co 2 FeAl 68 and Co 2 MnAl 69 . The changes in magnetic anisotropy associated with strain-induced tetragonal lattice distortion in Co 2 MnSi and Co 2 FeSi thin films were investigated by Pandey et al 70 , nevertheless, this approach neglected the presence of surface effects.…”

Role of scaffold network in controlling strain and functionalities of nanocomposite films

“…The magnetoelastic anisotropy energy along the film growth direction is given by K me = 3λ [001] Y [001] ε oop /2, where λ [001] is the magnetostriction coefficient along the [001] direction. Y [001] is given by Y = ( C 11 − C 12 )( C 11 + 2 C 12 )/( C 11 + C 12 ) ( 45 ), where the elastic constants for LSMO are C 11 = 2.27 × 10 12 dynes/cm 2 , C 12 = 1.58 × 10 12 dynes/cm 2 ( 46 ), and λ [001] ~100 ppm ( 47 ). ε oop is the strain along the out-of-plane direction.…”

Magnetic Hysteresis in Nanocomposite Films Consisting of a Ferromagnetic AuCo Alloy and Ultrafine Co Particles

“…A different scenario is that in which a mechanical stress is produced in the magnetic film due to the bonding with the substrate [ 10 ], opening the possibility of exploiting the magnetoelastic coupling to tune the magnetic anisotropy [ 11 , 12 , 13 ]. Tailoring the anisotropy is crucial in the field of magnetic sensors where, moreover, flexible substrates are now often employed [ 14 , 15 ].…”