Switching of magnetic anisotropy in epitaxial CoFe₂O₄thin films induced by SrRuO₃buffer layer

Abstract

The magnetic anisotropy of epitaxial spinel ferrite CoFe 2 O 4 films grown on SrTiO 3 substrates by pulsed laser deposition can be reoriented by inserting a thin SrRuO 3 buffer layer. Without SrRuO 3 , the CoFe 2 O 4 films show a uniaxial anisotropy with the easy axis perpendicular to the film plane, while inserting a SrRuO 3 buffer layer results in the switching of the easy axis into the in-plane orientation. This is associated with a tensile and a compressive strain for the films without and with buffer layer, respectively, which is also correlated with the different density of interfacial misfit dislocations. As a result, the ferrite films can be effectively tailored by using SrRuO 3 .

Epitaxial strain effects in the spinel ferritesCoFe2O4andNiFe2O

“…For sufficient amount of strain the easy axis of magnetization will therefore always be oriented either in-plane or out-of-plane, consistent with various experimental observations in thin CoFe 2 O 4 films under tensile strain. 13,14,48 According to the phenomenological magnetoelastic theory for a cubic crystal discussed in Sec. II B, in particular Eqs.…”

Perpendicular magnetic anisotropy in 70nm CoFe2O4 thin films fabricated on SiO2/Si(100) by the sol–gel method

“…[1][2][3][4][5][6][7][8]. The modification of magnetic and dielectric properties of CFO can be realized through substitution [9][10][11], fabrication of monodispersed purified hollow ferrite spheres [12] and growth of CFO films on different substrates using various techniques such as sputtering, molecular beam epitaxy, pulsed laser deposition and sol-gel method [3,4,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Considering practical applications in magnetic recording, the sol-gel method is an attractive alternative to other deposition methods due to its advantages such as lower annealing temperature, easier composition control, non-vacuum process and easier fabrication of large area thin films [21,23].…”

High‐Density Periodically Ordered Magnetic Cobalt Ferrite Nanodot Arrays by Template‐Assisted Pulsed Laser Deposition

“…From the inserted enlarged loops, the in-plane coercive field can be determined as around $170 Oe, which is much smaller than that of an epitaxial CFO film on a SRO/STO substrate ($3 000 Oe). [26] In epitaxial CFO films, the large coercivity can be ascribed to magnetostrictive, magnetocrystalline, and shape anisotropies, among which the magnetostrictive anisotropy from clamping strain is the dominating factor. [3,26] In our CFO islands, the magnetostrictive anisotropy can be greatly reduced by fast relaxation of the strain from the island edges, while the shape anisotropy and crystalline anisotropy can be released by forming noncontinuous islands and polycrystallites, respectively.…”

“…[26] In epitaxial CFO films, the large coercivity can be ascribed to magnetostrictive, magnetocrystalline, and shape anisotropies, among which the magnetostrictive anisotropy from clamping strain is the dominating factor. [3,26] In our CFO islands, the magnetostrictive anisotropy can be greatly reduced by fast relaxation of the strain from the island edges, while the shape anisotropy and crystalline anisotropy can be released by forming noncontinuous islands and polycrystallites, respectively. Although the dipole-dipole interactions among dots add to the anisotropy, they are too weak compared to the internal anisotropy.…”