Permalloy thin films on MgO(001): Epitaxial growth and physical properties

Abstract

Permalloy thin films were deposited onto MgO(001) substrates by standard sputtering technique at growth temperatures ranging from 200 to 800 °C. Both reflection high-energy electron diffraction (RHEED) experiments and atomic force microscopy observations reveal that the substrate temperature for two-dimensional epitaxial growth should not exceed 350 °C. A series of permalloy films with thicknesses ranging from 3.5 to 100 nm was prepared at 300 °C. All films were grown as (001) single crystal with the same crystallographic orientations as the MgO(001) substrates. As evidenced by RHEED and x-ray diffraction, films with thicknesses larger than about 20 nm present a structural relaxation. The in-plane magnetization hysteresis loops obtained by longitudinal Kerr loop measurements exhibit a 〈100〉 fourfold cubic anisotropy and an enhancement of the magnetic softness with decreasing film thickness, both likely originating from the large interfacial strain configuration.

Magnetotransport effects of ultrathin Ni80Fe20films probedin situ

“…This gives rise to a non-negligible shape anisotropy and increases the coercivity significantly in comparison to the value of ≤ 1 mT for a homogeneous Ni 80 Fe 20 thin film. 14,15 Due to the statistical distribution of island sizes and separations, these magnetic phases will not occur exclusively in a certain thickness range, but rather show a gradual transition with increasing thickness.…”

Thermally assisted interlayer magnetic coupling through Ba0.05Sr0.95TiO3 barriers

“…The FMR results are consistent with the XRD ones that reveal the presence of different orientations of Py in the multilayers and agree with previous references. 10,21 The LSMO layer also shows a cubic magnetic anisotropy 22 as expected from the pseudo-cubic structure of the compound with K 4 % 1.5 Â 10 4 erg/cm 3 at 250 K.…”

“…This choice has been done taking into account that high-quality Py films can be grown onto oxide substrates in spite of the large lattice mismatch at Py/OX interfaces and its soft magnetic properties. 10 The characteristics of ferromagnetic (FM)/barrier interfaces, 11 i.e., creation of ultrathin magnetic layers by charge transfer 12 and/or the existence of magnetic "dead" layers 13 at them, are known to play a crucial role in the tunneling magneto-resistance effect. Oxide-based interfaces are particularly reactive and the exchange-bias effect is usually observed in these systems arisen from the appearance of antiferromagnetic layers at the interface of magnetic/non-magnetic layers.…”

Quantum Spin-Wave Materials, Interface Effects and Functional Devices for Information Applications

“…Similarly, spin-wave materials have been rapidly developed by the introduction of spin-wave functional devices. During the last few decades, in-depth investigations have shown that magnetic materials, such as YIG (Dubs et al, 2017), permalloy (Michelini et al, 2002), CoFeB (Conca et al, 2013) and Heusler alloy (Kubota et al, 2009) provide clear advantages as spin-wave carriers. Chumak et al (2017) summarized the magnetization parameters and spin-wave characteristics of the abovementioned four typical spin-wave materials, and concluded that the spin-wave materials should have four basic requirements: a) a small-value Gilbert damping constant that ensures that propagation of spin waves without excessive dissipation; b) a high saturation magnetization that ensures sufficient spin-wave frequency and group velocity; c) a highvalue Curie temperature that provides thermal stability; and d) ease of processing.…”