The room temperature deposition of high-quality epitaxial yttrium iron garnet thin film via RF sputtering
Introduction
Ferrimagnetic yttrium iron garnet (Y3Fe5O12, YIG) has attracted researchers' decades of attention for application in microwave devices and spintronics due to its relatively high Curie temperature (TC ∼ 550 K), excellent magneto-optic Kerr effect [1], [2] and low magnetic loss [3], [4], [5]. Various techniques have been used to fabricate YIG thin films, such as Liquid Phase Epitaxy (LPE) [2], [6], Pulsed Laser Deposition (PLD) [7], [8], [9] and Radio Frequency (RF) magnetron sputtering [10], [11], [12]. Although LPE and PLD are wellknown for growing single-crystalline thick film with high quality and high deposition rate, respectively, RF magnetron sputtering is better at producing thin film with smooth sample surface and stable stoichiometric ratio, which is more recognized by industries and suit for massive production. Previous study indicates epitaxial growth of YIG films with high quality using sputtering requires high processing temperature (above 750 °C), which hinders its wide application [13], [14]. Although other growth method was applied to solve this problem, such as post-annealing process after deposition at low temperature, especially on some non-garget substrates such as silicon or quartz which could be widely used in large-scale practical production [10], [12], [15], there is few study to comprehensively analyze the effect of post-annealing process on YIG thin film grown on garnet substrates. It will be very important for industrial community if epitaxial YIG thin films could be massively produced on garnet substrates after being deposited at room temperature then annealed at high temperature. In this case, it will not be so critical for the choice of film-growth facility, especially for those without heater. And it will be quite efficient once large batches of films could be annealed in a furnace at the same time. Most importantly, this technique will benefit many devices which cannot stand for a long period at a relatively high temperature. In this work, epitaxial YIG thin films were grown on (111)-oriented gadolinium gallium garnet (Gd3Ga5O12, GGG) substrates at room temperature by RF sputtering then annealed at high temperatures. By a series of systematical analysis of both structural and physical properties of YIG thin films prepared via different routes, we found that the physical properties of those films are comparable with that grown under high temperatures, presenting a proper way to obtain engineering desired ferrites through carefully tuning their growth conditions.
Section snippets
Experimental section
All the YIG thin films were grown on paramagnetic (111)-oriented GGG substrate (lattice parameter a = 12.383 Å), which has a theoretically small lattice mismatch of ∼0.06% compared with that of bulk YIG (lattice parameter a = 12.376 Å). The growth atmosphere was pure argon with a pressure of 0.02 mbar when YIG thin films were grown at room temperature (RT) for 8 h, followed by two different post-annealing treatments. During the annealing, these YIG thin films were kept in pure oxygen gas at
Results and discussion
In order to verify the crystallinity of HT- and RT-YIG thin films, θ-2θ scans, ϕ scans and RSMs by XRD were adopted. Fig. 1(a) shows the θ-2θ spectra of YIG/GGG (111) thin films grown at different high temperatures under 0.02 mbar in a certain atmosphere consisting of equal ratio of argon and oxygen. As shown in this figure, single-crystal YIG phase begins to form when the deposition temperature is increased to 750 °C, which agrees with previous studies [13], [14]. The only preferred
Conclusions
In summary, post-annealing process was used to crystallize YIG thin films on GGG (111) substrates deposited at room temperature. We found those RT-deposited YIG thin films were highly crystalized along (444) direction after annealing at high temperature except that some dislocations were generated. But, their magnetic property and ferromagnetic resonance were comparable with that of HT-deposited YIG thin films. So, RT-deposition plus post-annealing is a practical and simple technique to grow
Acknowledgments
The work was supported by the National Natural Science Foundation of China (Nos: 61631166004, 61471290, 51390472 and 51202185), the SRFDP-RGC Joint Research Project 2013/14 (20130201140002), National 973 projects of China (No. 2015CB654603), and the Research Grant Council of HKSAR via SRFDP-RGC Joint Research Scheme M-HKUST605/13.
References (29)
- et al.
Preparation of two-dimensional yttrium iron garnet magnonic crystal on porous silicon substrate
Mater. Lett.
(2014) - et al.
Magnetic properties of pulsed laser ablated YIG thin films on different substrates
J. Magn. Magn. Mater.
(2004) - et al.
The influence of substrate temperature and annealing on the properties of pulsed laser-deposited YIG films on fused quartz substrate
J. Magn. Magn. Mater.
(2008) - et al.
Effect of deposition temperature on the properties of sputtered YIG films grown on quartz
Mater. Chem. Phys.
(2010) - et al.
Advances in the growth and characterization of magnetic, ferroelectric, and multiferroic oxide thin films
Mater. Sci. Eng. R Rep.
(2010) - et al.
Optical spectroscopy of sputtered nanometer-thick yttrium iron garnet films
J. Appl. Phys.
(2015) - et al.
Large magneto-optic enhancement in ultra-thin liquid-phase-epitaxy iron garnet films
Appl. Phys. Lett.
(2015) - et al.
FMR linewidths of YIG films fabricated byex situpost-annealing of amorphous films deposited by RF magnetron sputtering
Phys. Status Solidi (a)
(2007) - et al.
Ferromagnetic resonance of sputtered yttrium iron garnet nanometer films
J. Appl. Phys.
(2014) - et al.
Large spin pumping from epitaxial Y3Fe5O12thin films to Pt and W layers
Phys. Rev. B
(2013)
Ferromagnetic resonance properties of LPE YIG films
IEEE Trans. Magn.
Physico-chemical characterization of multilayer YIG thin film deposited by rf sputtering
Eur. Phys. J. Appl. Phys.
Effect of post-annealing on the magnetic properties of BiYIG film by RF magnetron sputtering on Si substrates
IEEE Trans. Magn.
YIG thin films for magneto-optical and microwave applications
Appl. Phys. status solidi (c)
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