Iron garnets that combine robust perpendicular magnetic anisotropy (PMA) with low Gilbert damping are desirable for studies of magnetization dynamics as well as spintronic device development. This paper reports the magnetic properties of low‐damping bismuth‐substituted iron garnet thin films (Bi0.8Y2.2Fe5O12) grown on a series of single‐crystal gallium garnet substrates. The anisotropy is dominated by magnetoelastic and growth‐induced contributions. Both stripe and triangular domains form during field cycling of PMA films, with triangular domains evident in films with higher PMA. Ferromagnetic resonance measurements show damping as low as 1.3 × 10−4with linewidths of 2.7 to 5.0 mT. The lower bound for the spin‐mixing conductance of BiYIG/Pt bilayers is similar to that of other iron garnet/Pt bilayers.
Rare‐earth iron garnets (REIG) have recently become the materials platform of choice for spintronic studies on ferrimagnetic insulators. However, thus far the materials studied have mainly been REIG with a single rare earth species such as thulium, yttrium, or terbium iron garnets. In this study, magnetometry, ferromagnetic resonance, and magneto‐optical Kerr effect imaging is used to explore the continuous variation of magnetic properties as a function of composition for Y
- Award ID(s):
- 1911792
- NSF-PAR ID:
- 10449173
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Electronic Materials
- Volume:
- 7
- Issue:
- 10
- ISSN:
- 2199-160X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
Abstract -
Abstract Magnetic insulators, such as the rare‐earth iron garnets, are promising materials for energy‐efficient spintronic memory and logic devices, and their anisotropy, magnetization, and other properties can be tuned over a wide range through selection of the rare‐earth ion. Films are typically grown as epitaxial single crystals on garnet substrates, but integration of these materials with conventional electronic devices requires growth on Si. The growth, magnetic, and spin transport properties of polycrystalline films of dysprosium iron garnet (DyIG) with perpendicular magnetic anisotropy (PMA) on Si substrates and as single crystal films on garnet substrates are reported. PMA originates from magnetoelastic anisotropy and is obtained by controlling the strain state of the film through lattice mismatch or thermal expansion mismatch with the substrates. DyIG/Si exhibits large grain sizes and bulk‐like magnetization and compensation temperature. Polarized neutron reflectometry demonstrates a small interfacial nonmagnetic region near the substrate. Spin Hall magnetoresistance measurements conducted on a Pt/DyIG/Si heterostructure demonstrate a large interfacial spin mixing conductance between the Pt and DyIG comparable to other garnet/Pt heterostructures.
-
Abstract Electric‐field‐controlled magnetism is of importance in realizing energy efficient, dense and fast information storage and processing. Strain‐mediated converse magneto‐electric (ME) coupling between ferromagnetic and ferroelectric heterostructure shows promise for realizing electric‐controlled magnetism at room temperature and is attracting a number of recent investigations. However, such ME‐effect studies have mainly focus on magnetic metals. In this work, high quality yttrium iron garnet (Y3Fe5O12(YIG)) films are deposited directly onto (100)‐oriented single‐crystal Pb (Mg1/3Nb2/3)0.7Ti0.3O3(PMN‐PT) substrates by means of magnetron sputtering. The electric‐field‐induced polarization switching and lattice strain in the PMN‐PT substrate results in two distinct magnetization states in the YIG film that are nonvolatile and electrically reversible. Because of the direct contact between the YIG and the PMN‐PT substrate, an efficient ME coupling and an almost 90° rotation of the easy axis of the YIG film can be realized. Furthermore, the electric‐field‐controlled hysteresis loop‐like ferromagnetic resonance field shifts and spin pumping signals are observed in Pt/YIG/PMN‐PT heterostructures. Thus, the obstacle is overcome via growing high‐quality YIG thin films directly onto PMN‐PT substrates and an efficient manipulation of magnetism and pure spin current transport by electric field is thereby realized. These findings are instructive for future low‐power magnetic insulator‐based spintronic devices.
-
This report is on the nature of strain in thin films of yttrium iron garnet (YIG) on yttrium aluminum garnet (YAG) substrates due to film-substrate lattice mismatch and the resulting induced magnetic anisotropy. Films with thickness 55 nm to 380 nm were deposited on (100), (110), and (111) YAG substrates using pulsed laser deposition (PLD) techniques and characterized by structural and magnetic characterization techniques. The in-plane strain determined to be compressive using X-ray diffraction (XRD). It varied from −0.12% to −0.98% and increased in magnitude with increasing film thickness and was relatively large in films on (100) YAG. The out-of-plane strain was tensile and also increased with increasing film thickness. The estimated strain-induced magnetic anisotropy field, found from XRD data, was out of plane; its value increased with film thickness and ranged from 0.47 kOe to 3.96 kOe. Ferromagnetic resonance (FMR) measurements at 5 to 21 GHz also revealed the presence of a perpendicular magnetic anisotropy that decreased with increasing film thickness and its values were smaller than values obtained from XRD data. The PLD YIG films on YAG substrates exhibiting a perpendicular anisotropy field have the potential for use in self-biased sensors and high-frequency devices.more » « less
-
Abstract Organic‐based magnetic materials have been used for spintronic device applications as electrodes of spin aligned carriers and spin‐pumping substrates. Their advantages over more traditional inorganic magnets include reduced magnetic damping and lower fabrication costs. Vanadium tetracyanoethylene, V[TCNE]
x (x ≈ 2), is an organic‐based ferrimagnet with an above room‐temperature magnetic order temperature (T c ≈ 400 K). V[TCNE]x has deposition flexibility and can be grown on a variety of substrates via low‐temperature chemical vapor deposition (CVD). A systematic study of V[TCNE]x thin‐film CVD parameters to achieve optimal film quality, reproducibility, and excellent magnetic properties is reported. This is assessed by broadband ferromagnetic resonance (FMR) that shows most narrow linewidth of ≈1.5 Gauss and an extremely low Gilbert damping coefficient. The neat V[TCNE]x films are shown to be efficient spin injectors via spin pumping into an adjacent platinum layer. Also, under an optimized FMR linewidth, the V[TCNE]x films exhibit Fano‐type resonance with a continuum broadband absorption in the microwave range, which can be readily tuned by the microwave frequency.