Effect of lattice strain on cobalt ferrite Co_0.75Fe_2.25O₄(111) thin films

Abstract

We report the optimum conditions for the epitaxial growth of CoxFe3−xO4 (CFO) (111) thin films with x = 0.75 on an α-Al2O3(0001) substrate via reactive RF magnetron sputtering. The lattice strain evaluated by X-ray diffraction measurements is as small as 0.11% in spite of the large lattice mismatch between CFO(111) and α-Al2O3(0001). The CFO(111) thin films grown under the optimal conditions exhibit magnetic anisotropy with the easy axis of magnetization perpendicular to the films. The induced uniaxial anisotropy energy can be quantitatively explained by the magnetoelastic effect.

Continuous strain-mediated perpendicular magnetic anisotropy in epitaxial (111) CoFe2O4 thin films grown on LiTaO3 substrates

“…23 However, there is a relatively large lattice mismatch between CFO (111) and Al 2 O 3 (0001). 24 LiTaO 3 is a multifunctional single crystal substrate material, and its crystal structure is similar to that of Al 2 O 3 . There is a smaller lattice mismatch and a larger difference in the thermal expansion coefficient between CFO and LiTaO 3 .…”

(001) preferred oriented CoFe2O4thin films on glass and Si substrates prepared by the metal-organic decomposition method

“…3) In addition, it is reported that applying in-plane tensile stress causes tetragonal strain, thereby overcoming the shape magnetic anisotropy and showing an easy axis of magnetization perpendicular to the plane. [4][5][6][7][8][9][10][11] Investigation of magnetic anisotropy by the magnetoelastic effect has been conducted by preparing CFO thin films on various substrates to apply tetragonal strain. [7][8][9][10][11][12][13][14][15][16][17] Since the lattice constant of CFO is slightly smaller than twice the lattice constant of MgO, and a lattice mismatch occurs when epitaxially grown.…”