Magnetic Properties and Growth‐Induced Anisotropy in Yttrium Thulium Iron Garnet Thin Films

Abstract

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 YxTm3−x iron garnet (YxTm3−xIG) thin films grown by pulsed laser deposition on gadolinium gallium garnet substrates. It is reported that the tunability of the magnetic anisotropy energy, with full control achieved over the type of anisotropy (from perpendicular, to isotropic, to an in‐plane easy axis) on the same substrate. In addition, a nonmonotonic composition‐dependent anisotropy term is reported, which is ascribed to growth‐induced anisotropy similar to what is reported in garnet thin films grown by liquid‐phase epitaxy. Ferromagnetic resonance shows linear variation of the damping and the g‐factor across the composition range, consistent with prior theoretical work. Domain imaging reveals differences in reversal modes, remanant states, and domain sizes in YxTm3−x iron‐garnet thin films as a function of anisotropy.

Stress-Induced Magnetic Properties of Gadolinium Iron Garnet Nanoscale-Thin Films: Implications for Spintronic Devices

“…Therefore, the net Fe 3+ sublattice can overcome the R 3+ moment, and a magnetic compensation temperature T comp may exist, e.g., at around 286 K for bulk gadolinium iron garnet (GdIG) . Thus, substituting Y with heavy rare earths like Tm, − Gd, , or Eu , leads to complex magnetic structures, and enables the tuning of the magnetic properties. ,− ,− …”

“…On the basis of eq , the expected values of K eff for different RIG thin films were calculated using the bulk parameters for the saturation magnetization M s , , λ 111 , K 1 and common values of Y = 2 × 10 11 N/m 2 and ν = 0.29 for all RIGs (for details refer to Table S1 in the Supporting Information, SI). In all cases, fully strained, (111) oriented thin films, to match a given substrate lattice constant a sub , are hereby assumed, neglecting further contributions to the magnetic anisotropy, e.g., growth-induced anisotropies, spin canting effects, or altered material parameters for thin films.…”

Tailoring magnetic domains with hard x-ray free-electron laser-printed gratings

“…2a. Domain patterns typical for YIG-based systems with out-of-plane anisotropy 23,[28][29][30][31][32] are present in the pristine regions of the sample. We note that the pristine regions exhibit an asymmetry between the widths of the out-of-plane domains pointing parallel and antiparallel to the film normal (areas of the bright and dark contrast).…”

“…2b-d). We attribute this to the presence of a small magnetic bias field present 33 , or, alternatively, non-zero remanent magnetization of the film 23 . The magnetic domain patterns are clearly different in the irradiated areas.…”

“…X-ray induced damage has so far also been observed in other magnetic oxides [41][42][43][44] . In the case of Tm:YIG, Fe 3+ and Fe 2+ as well as oxygen vacancies may be present in the film 23 . Their redistribution across inequivalent octahedral sites by the x-ray irradiation may modify the magnetocrystalline anisotropy and create a pinning potential in the irradiated areas.…”