Ultra-low damping in lift-off structured yttrium iron garnet thin films

Abstract

We show that using maskless photolithography and the lift-off technique patterned yttrium iron garnet thin films possessing ultra-low Gilbert damping can be accomplished. The films of the 70 nm thickness were grown on (001)-oriented gadolinium gallium garnet by means of pulsed laser deposition and exhibit high crystalline quality, low surface roughness and effective magnetization of 127 emu/cm 3 . The Gilbert damping parameter is as low as 5 × 10 −4 . The obtained structures have well-defined sharp edges which along with good structural and magnetic film properties, pave a path in the fabrication of high-quality magnonic circuits as well as oxide-based spintronic devices.Yttrium iron garnet (Y 3 Fe 5 O 12 , YIG) has become an intensively studied material in recent years due to exceptionally low damping of magnetization precession and electrical insulation enabling its application in research on spin-wave propagation 1-3 , spin-wave based logic devices 4-6 , spin pumping 7 , and thermally-driven spin caloritronics 8 . These applications inevitably entail film structurization in order to construct complex integrated devices. However, the fabrication of high-quality thin YIG films requires deposition temperatures over 500C 6,[9][10][11][12][13][14][15][16][17][18] leading to top-down lithographical approach that is ion-beam etching of a previously deposited plain film whereas patterned resist layer serves as a mask.Consequently, this method introduces crystallographic defects, imperfections to surface structure and, in the case of YIG films, causes significant increase of the damping parameter. [19][20][21] Moreover, it does not ensure well-defined structure edges for insulators, which play a crucial role in devices utilizing

Nanoscale X-ray imaging of spin dynamics in yttrium iron garnet

“…A YIG film of 185 nm thickness was grown by liquid phase epitaxy (LPE) on (111)-oriented GGG 36 . Ferromagnetic resonance measurements showed a saturation magnetization of M S = (143 ± 2) kA/m and a Gilbert damping coefficient of α = 1.3 · 10 −4 , which both agree well with typical values for YIG films in literature 4,[36][37][38] . The film was subsequently processed using a "FEI Dual Beam System Helios NanoLab 460F1" focused ion beam (FIB).…”

Direct observation of coherent magnons with suboptical wavelengths in a single-crystalline ferrimagnetic insulator

“…Gilbert damping coefficients of α = 0.3 × 10 −4 (185 nm) and α = 1.9 × 10 −4 (80 nm) have been determined via ferromagnetic resonance measurements. Both quantities agree well with typical values for YIG films in literature [7,27,34]. Stripline antennas of copper, each 2 μm wide and 80 nm thick [cf.…”

Low-damping ferromagnetic resonance in electron-beam patterned, high-Q vanadium tetracyanoethylene magnon cavities

“…The thinfilm damping result of (3.98 ± 0.22) × 10 −5 places V[TCNE] x films comfortably alongside YIG films as the lowest magnetic damping material currently available, and the retention of that ultra-low damping after patterning is considerably better than the reported values for patterned YIG structures. [10][11][12][13][14] In addition to low-damping, the high-frequency measurements of the thin film and 25 µm disks have Quality (Q) factors, f ∆ f , of over 3,700, competitive with Q factors for YIG thin films. 48 Retaining ultra-low damping and high Q in patterned V[TCNE] x for features as small as 25 µm and as large as millimeters, both relevant length scales for many magnonic cavity applications, 3,14,[49][50][51][52] combined with the flexibility to deposit on most inorganic substrates, positions V[TCNE] x to complement YIG in magnonic and magnetoelectric devices where integration of GGG or high-temperature annealing steps is limiting, such as for small form factors and on-chip integration.…”