Magnetic properties and domain structure of ultrathin yttrium iron garnet/Pt bilayers

Abstract

We report on the structure, magnetization, magnetic anisotropy, and domain morphology of ultrathin yttrium iron garnet (YIG)/Pt films with thickness ranging from 3 to 90 nm. We find that the saturation magnetization is close to the bulk value in the thickest films and decreases towards low thickness with a strong reduction below 10 nm. We characterize the magnetic anisotropy by measuring the transverse spin Hall magnetoresistance as a function of applied field. Our results reveal strong easy plane anisotropy fields of the order of 50-100 mT, which add to the demagnetizing field, as well as weaker in-plane uniaxial anisotropy ranging from 10 to 100 $\mu$T. The in-plane easy axis direction changes with thickness, but presents also significant fluctuations among samples with the same thickness grown on the same substrate. X-ray photoelectron emission microscopy reveals the formation of zigzag magnetic domains in YIG films thicker than 10 nm, which have dimensions larger than several 100 $\mu$m and are separated by achiral Néel-type domain walls. Smaller domains characterized by interspersed elongated features are found in YIG films thinner than 10 nm.

10 pages, 8 figures

References in corpus (2)

• Theory of spin Hall magnetoresistance
• Simultaneous detection of the spin-Hall magnetoresistance and the spin-Seebeck effect in Platinum and Tantalum on Yttrium Iron Garnet

Cited by in corpus (14)

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• Magnetoelectric effects in Josephson junctions
• Magnetization reversal in S/F/S Josephson junctions on a 3D topological insulator
• Spin-Wave Doppler Shift by Magnon Drag in Magnetic Insulators
• Current-induced switching of YIG/Pt bilayers with in-plane magnetization due to Oersted fields
• Long-range interaction of magnetic moments in a coupled system of S/F/S Josephson junctions with anomalous ground-state phase shift
• Nonlinear longitudinal and transverse magnetoresistances due to current-induced magnon creation-annihilation processes
• Hysteresis and chaos in anomalous Josephson junctions without capacitance
• Controllable magnetic states in chains of coupled phi-0 Josephson junctions with ferromagnetic weak links
• Thermally induced spin torque and domain wall motion in superconductor/antiferromagnetic insulator bilayers
• Estimation of spin-orbit torques in the presence of current-induced magnon creation and annihilation
• Giant quadratic magneto-optical response of thin YIG films for sensitive magnetometric experiments