Anomalous magnetoresistance in Fibonacci multilayers

Abstract

The present paper theoretically investigates magnetoresistance curves in quasiperiodic magnetic multilayers for two different growth directions, namely [110] and [100]. We considered identical ferromagnetic layers separated by non-magnetic layers with two different thicknesses chosen based on the Fibonacci sequence. Using parameters for Fe/Cr multilayers, four terms were included in our description of the magnetic energy: Zeeman, cubic anisotropy, bilinear and biquadratic couplings. The minimum energy was determined by the gradient method and the equilibrium magnetization directions found were used to calculate magnetoresistance curves. By choosing spacers with a thickness such that biquadratic coupling is stronger than bilinear coupling, unusual behaviors for the magnetoresistance were observed: (i) for the [110] case there is a different behavior for structures based on even and odd Fibonacci generations; and more interesting, (ii) for the [100] case we found magnetic field ranges for which the magnetoresistance increases with magnetic field.

The Fibonacci quasicrystal: case study of hidden dimensions and multifractality

“…Magnetic multilayers composed of Fe/Cr layers and studied by MOKE (magneto-optic Kerr effect) and FMR (ferromagnetic resonance) should display self-similar magnetization versus curves and interesting thermodynamic signatures (Bezerra et al, 2001). Another promising system is composed of epitaxially grown layers of Fe and Au using ultra-high-vacuum vapor deposition (Suwa et al, 2017) which were theoretically predicted to have anomalous magnetoresistance (Machado et al, 2012).…”

Enhanced Magneto-Optical Activities of Modulated Fe - Pt Multilayer Metamaterials

“…It is anticipated that broken short-range translational symmetry in magnetic multilayers leads to modulation in exchange coupling between magnetic layers, resulting in intriguing magnetic phenomena [26][27][28][29]. Indeed, modulated magnetic multilayer metamaterials were theoretically predicted to give rise to anomalous magnetic resistance [30] and ferromagnetic resonance [31], and were experimentally demonstrated to bring about quasi-isotropic magnetization [32]. Nevertheless, enhancement of light-matter interaction in such modulated magnetic multilayer metamaterials has yet to be explored experimentally.…”

Magnetic Properties of Fibonacci-Modulated Fe-Au Multilayer Metamaterials

“…In particular, much attention has been paid to iron-gold (Fe-Au) PMs, because these PMs have demonstrated not only perpendicular magnetization but also oscillatory coupling between ferromagnetic layers caused by the Ruderman-Kittel-Kasuya-Yosida interaction [ 9 ] and enhanced magneto-optical Kerr effects [ 10 ]. In contrast to the periodic counterpart, magnetic quasi-periodic multilayers remain experimentally unaddressed, although theoretical calculations have predicted anomalous magnetic resistance [ 11 ] and ferromagnetic resonance (FMR) [ 12 ].…”