Field-dependent anisotropic magnetoresistance and planar Hall effect in epitaxial magnetite thin films

Abstract

A systematic study of the temperature and magnetic field dependence of the longitudinal and transverse resistivities of epitaxial thin films of magnetite (Fe 3 O 4 ) is reported. The anisotropic magnetoresistance (AMR) and the planar Hall effect (PHE) are sensitive to the in-plane orientation of current and magnetization with respect to crystal axes in a way consistent with the cubic symmetry of the system. We also show that the AMR exhibit sign reversal as a function of temperature, and that it shows significant field dependence without saturation up to 9 T. Our results provide a unified description of the anisotropic magnetoresistance effects in epitaxial magnetite films and illustrate the need for a full determination of the resistivity tensor in crystalline systems.

Asymmetric anisotropic magnetoresistance in epitaxial Fe3O4 thin films

“…Eqs. (1) and (2) are applied to polycrystalline samples as well as epitaxial films [11][12][13], whereas in epitaxial thin films, the effect of crystalline symmetry should be revealed in the AMR effect owing to the spinorbit coupling, which reflects the contribution of the crystalline structure [14][15][16][17][18]. Also, there still lack of a full understanding of how the current orientation influences AMR properties.…”

Magnetoelectric properties of epitaxialFe3O4thin films on (011) PMN-PT piezosubstrates

“…Thus, the fourfold symmetry is detectable at room temperature in our magnetite films epitaxially grown on (011) PMN-PT, while such contribution was observed for the (001)-oriented Fe 3 O 4 films only on cooling below 200 K and related to the polaron formation. 15,19,20 No such report on the angular dependence of MR is known to us so far on the 13 similar for both unpoled and poled states between 300 K (Fig. 6(a), 6(e)) and 150 K (Fig.…”

Transversal magneto-resistance in epitaxial Fe3O4 and Fe3O4/NiO exchange biased system

“…8,12,13 In their analysis, Naftalis et al have shown that the magnetic field and temperature dependence of the four fitting parameters A, B, C, and D suggests the need for a more precise microscopic theory for magnetotransport properties. 8 The transversal MR has been used as a tool to study inplane magnetization processes, 14 sensing of low magnetic fields, 5 magnetic micro-bead detection, 15 and compass applications. 3 The possibility of using this effect in non-volatile memory devices 16 has also been considered.…”

“…5,6 The drawbacks associated with longitudinal AMR measurements can be greatly overcome by measuring the voltage change in the transversal direction instead. [7][8][9] The origin of the transversal MR is believed to be closely related to the AMR, 7 which is due to anisotropic electron scattering induced by the spinorbit interaction. 10 In a simple but common situation for a ferromagnetic (FM) film with a single in-plane magnetic domain, the angular dependencies of the longitudinal and transversal resistivities are given by…”

“…8,[11][12][13] The suggested equations in the case of crystalline systems with growth direction along [001] are…”