Origin of perpendicular magnetic anisotropy in amorphous thin films

Abstract

The emergence of perpendicular magnetic anisotropy (PMA) in amorphous thin films, which eventually transforms the magnetic spins form an in-plane to the out-of-plane configuration, also known as a spin-reorientation transition (SRT), is a fundamental roadblock to attain the high flux concentration advantage of these functional materials for broadband applications. The present work is focused on unfolding the origin of PMA in amorphous thin films deposited by magnetron sputtering. The amorphous films were deposited under a broad range of sputtering pressure (1.6–6.2 mTorr), and its effect on the thin film growth mechanisms was correlated to the static global magnetic behaviours, magnetic domain structure, and dynamic magnetic performance. The films deposited under low-pressure revealed a dominant in-plane uniaxial anisotropy along with an emerging, however feeble, perpendicular component, which eventually evolved as a dominant PMA when deposited under high-pressure sputtering. This change in the nature of anisotropy redefined the orientation of spins from in-plane to out-of-plane. The SRT in amorphous films was attributed to the dramatic change in the growth mechanism of disorder atomic structure from a homogeneously dispersed to a porous columnar microstructure. We suggest the origin of PMA is associated with the columnar growth of the amorphous films, which can be eluded by a careful selection of a deposition pressure regime to avoid its detrimental effect on the soft magnetic performance. To the author’s best knowledge, no such report links the sputtering pressure as a governing mechanism of perpendicular magnetisation in technologically important amorphous thin films.

LiAlO2-Modified Li Negative Electrode with Li10GeP2S12 Electrolytes for Stable All-Solid-State Lithium Batteries

“…In addition, LiAlO 2 layers with thicknesses of 100 and 300 nm were also fabricated on the surface of lithium, as shown in Figure S2. XPS was used to characterize LiAlO 2 due to its amorphous nature Figure d shows the XPS results of the LiAlO 2 layer.…”

“…XPS was used to characterize LiAlO 2 due to its amorphous nature. 31 Figure 2d shows the XPS results of the LiAlO 2 layer. The peak at 530.6 eV corresponds to the O 1s in LiAlO 2 (Figure 2e), and the peak at 55.1 eV, which is assigned to the Li 1s (Figure 2f) in the LiAlO 2 layer, is different than that of lithium metal (55.4 eV).…”

Engineering buffer layers to improve temperature resilience of magnetic tunnel junction sensors

“…Overall, for samples grown at 4.5 mTorr, a clear increase in H c followed by an earlier steep decrease is visible, indicative of a larger amount of AFM dragged spins. This effect may be due to higher local disorder at the interface as a consequence of higher deposition pressure [38]. In fact, Tang et al [24] showed that H ex depends strongly on the deposition atmosphere, reporting higher values when the pressure was lower.…”

Longitudinal Magneto-Optical Kerr Effect of Nanoporous CoFeB and W/CoFeB/W Thin Films

“…Of particular interest is the design and fabrication of special nano-structured thin films, including magnetic layers, for the regulation of MOKE rotation inverse and the related reversal mechanism study. To date, various nanostructures, including periodic rectangular apertures [35], optical Tamm-state structures [36,37], and prism-coupled surface-plasmon-resonance systems [38,39], have been investigated to enhance sensing performance assisted by a variety of fabrication methods, such as electrochemical deposition [40,41] and magnetron sputtering [42].…”