• Journal of Magnetics
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• v.14 no.3
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• pp.108-113
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• 2009

High-coercive garnet films have certain parameters suitable for creating reconfigurable magnetic atomic chips with visible geometry. However, the inner stresses and morphological properties, namely, networks of dislocations, layering and surface relief, and dependence of coercivity on thickness must be taken into account. Select features of films important for atomic trap creation have been studied experimentally and the supposed traps concept provided.

• Journal of the Korean Magnetics Society
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• v.8 no.6
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• pp.350-356
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• 1998

$Y_{3-x}La_xFe_5O_{12}$ (x=0.0, 0.25, 0.5, 0.75, 1.0) powders and thin films were fabricated by a sol-gel method and their magnetic properties and crystal structure were investigated by using X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and Mossbauer spectroscopy. XRD and Mossbauer spectroscopy measurements show that garnet powders annealed at 900 $^{\circ}C$ for 8 hours were single-phased and that thin films fired at 800 $^{\circ}C$ for 2 hours were crystallized without any preferred direction. X-ray diffraction patterns of $Y_{3-x}La_xFe_5O_{12}$ powders annealed at 1000 $^{\circ}C$ had only peaks of the garnet structure in case of x$\leq$0.75 but those of $Y_2LaFe_5O_{12}$ powders consisted of peaks from garnets and $LaFeO_3$. Mossbauer sepectra of garnet powders grown by the sol-gel method had a similar shape of those of powders grown by a conventional ceramic method. Grain sizes of garnet powders were 200~300 nm and the averaged surface roughness was 3.17 nm. Results of VSM measurements show the powders and thin films had soft magnetic properties and that the garnet powders had the largest saturation magnetization, 30 emu/g, and the lowest coercivity, 52 Oe.

• Journal of the Korean Magnetics Society
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• v.17 no.6
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• pp.246-252
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• 2007

This paper describes the effect of the mixing ratio of starting materials and the growth parameters of magnetic garnet films by LPE on the properties of the films and suggests the conditions to obtain the films suitable for the Faraday rotators of the optical CTs. The properties of the films investigated for the evaluation of the films were thickness, surface morphology, X-ray diffraction, lattice constant, lattice mismatch between film and substrate (single crystal nonmagnetic wafer), and Faraday rotation angle. Optical CTs have been fabricated and evaluated using the films grown.

• Journal of the Korean Magnetics Society
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• v.4 no.3
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• pp.214-218
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• 1994

$Y_{3}Fe_{5}O_{12}$ based garnet films(thin or thick) offer a great promise for the application of microwave communication components. We investigated the magnetic and crystallographic preperties of $Y_{3}Fe_{5}O_{12}$ thick films prepared by KrF eximer laser ablation of a stoichiometric garnet target. It was possible to obtain almost epitaxially oriented films on $Al_{2}O_{3}$(1102) plane. Although the crystalline quality depends on substrate temperature and $O_{2}$ partial pressure used($Po_{2}$), 4.1m thick films of $4{\pi}M_{s}=1300$ Gauss and $H_{c}=37.5$ Oe were obtained at the substrate temperature of $700^{\circ}C$ with the $Po_{2}$ of 100 mTorr after annealing the as-deposited films at $700^{\circ}C$ for 2 hours. These films are expected to be used for magnetostatic spin wave filters at narrow bandwidth frequency.

• The Korean Journal of Ceramics
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• v.1 no.2
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• pp.91-95
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• 1995

Polycrystalline bismuth- and aluminum- substituted dysporsium and yttrium iron garnet (Bi2R3-xAlyFe5-yO12, R=Dy or Y, $0\leqx\leq3, \; 0\leqy\leq3$) films have been prepared by pyrolysis. The crystallization temperatures, the solubility limit of bismuth ions into the garnet phase, and magnetic and magneto-optic properties of the films have been investigated as a function of bismuth and aluminum concentration. It was found that the crystallization temperatures as a function of bismuth and aluminum concentration. It was found that the crystallization temperatures of these films rapidly decreased as bismuth concentration. It was found that the crystallization temperatures of these films rapidly decreased as bismuth concentration (x) increased up to x=1.5 and then remained temperatures of these films rapidly decreased as bismuth concentration (x) increased up to x=1.5 and then remained unchanged at x>1.5, whereas, showed no changes as aluminum concentration (y) increased up to y=1.0 and then gradually increased at y>1.0. The solubility limit of bismuth ions was x=1.8 when y=0 but increased to x=2.3 when y=1.0. It was demonstrated that the magnetic and magneto-optic properties of the dysprosium iron garnet films could be tailored by bismuth and aluminum substitution suitable for magneto-optic recording as follows. The saturation magnetization and coercivity data obtained for the films indicated that the film composition at which the magnetic compensation temperature became room temperature was y=1.2 when x=1.0. Near this composition the coercivity and the squareness of the magnetic hysteresis loop of the films were several kOe and unit, respectively. The Curie temperatures of the films increased with the increase of x but decreaed with the increase of y, and was 150-$250^{\circ}C$ when x=1.0 and y=0.6-1.4. The Faraday rotation at 633 nm of the films increased as x increased but decreased as y increased, and was 1 deg/$\mu\textrm{m}$ when x=1.0 and y=1.0. Based on the data obtained, the appropriate film composition for magneto-optic recording was estimated as near x=1.0 and y=1.0 or $BiDy_2AlFe_4O_{12}$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.3
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• pp.257-262
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• 2001

Single crystalline films of La doped YIG(yttrium iron garnet) were grown by the liquid phase epitaxy. The lattice constants of films obtained by DCD(double crystalline diffractometer) measurement increased with increasing La contents in films. In particular, lattice constants of films grown wiht Y/La=20 solution were nearly same as those of GGG (gadolinium gallium garnet) substrate. The saturation magnetization measured with VSM (vibrating sample magnetometer) was about 1750Gauss which is the same as that of pure YIG irrespective of La contents in films. FMR(ferromagnetic resonance) linewidth of La doped YIG was smaller than that of pure YIG. Since appropriate La doping decreases the lattice mismatch between film and substrate, the FMR linewidth was Y/La=20 in this experiment.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.720-725
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• 1995

Bi-substituted gadolinium iron garnet films were deposited on GGG(111) and NGG (111) substrates by irradiating KrF excimer laser onto targets having compositions of $Bi_{x}Gd_{3-x}Fe_{5}O_{12}$ ($2.0{\leq}x{\leq}3.0$) under substrate temperature of $580~620^{\circ}C$. Analysis on structure, composition and angle of Faraday rotation, ${\theta}_{F}$, were carried out. The composition, the structure and the magneto-optical properties of the obtained films were found to be strongly dependent both on the compositions of the targets and on the pressure of oxygen. Before annealing in air, all films showed ${\theta}_{F}{\geq}0$ at ${\lambda}=6328{\AA}$, while several films showed ${\theta}_{F}{\leq}0$ after the annealing. The highest value of Bi-substitution up to x = 1.76 with uniform composition was obtained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1988.10a
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• pp.47-49
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• 1988

This paper discusses dynamic properties of bubble garnet thin films. The dynamic properties considered are Gilbert damping parameters, saturation velocity, and wall mobility. The parameters are evaluated to facilitate the search for desirable garnet thin film compositions. Given bubble diameter and Q-value, the computer prints out all compositions which meet the desired requirements. The computer model determines magnetization, anisotropy, damping, velocity, mobility among others from the film compositions. The computer modeling program is described by an algorithm detailing its operation.

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.109.1-109
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• 2002

• Journal of the Korean Ceramic Society
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• v.36 no.3
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• pp.293-300
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• 1999

고주파 마그네트론 스퍼터법을 이용한 YIG(yttrium iron garnet)박막 제조시 기판유형, 기판온도, 스퍼터전력, 스퍼터가스 등의 증착변수와 증착후 열처리 조건이 YIG 박막의 결정성, 화학조성, 미세구조 그리고 자기적 특성에 미치는 영향에 대하여 고찰하였다. 75$0^{\circ}C$ 이상의 온도에서 수행한 증착후 열처리에 의하여 비정질 박막이 결정화되었으며, 특히 GGG(gadolinium gallium garnet)기판 위에 제조된 박막은 강한 (111)우선배향성을 나타냈다. 박막조성은 스퍼터가스 내의 산소분율에 민감하게 영향을 받았으며, 산소분율이 20%인 스퍼터가스를 사용하여 제조된 박막은 Y2.88Fe3.84O12의 조성을 나타내었다. 증착후 열처리 온도가 90$0^{\circ}C$로부터 110$0^{\circ}C$로 증가함에 따라, GGG 기판위의 박막의 표면거칠기는 2.5nm에서 40nm로 증가하였으며, 보자력과 강자성 공명 선폭은 감소하였다.