Double-Layered Polycrystalline Iron Garnet Structure of Bi3Fe5O12 and Y3Fe5O12 grown on SiO2 substrates by pulsed laser deposition (original) (raw)
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Giant Faraday rotation in Bi x Ce 3-x Fe 5 O 12 epitaxial garnet films
Thin films of Bi x Ce 3-x Fe 5 O 12 with x = 0.7 and 0.8 compositions were prepared by using pulsed laser deposition. We investigated the effects of processing parameters used to fabricate these films by measuring various physical properties such as X-ray diffraction, transmittance, magnetization and Faraday rotation. In this study, we propose a phase diagram which provides a suitable window for the deposition of Bi x Ce 3-x Fe 5 O 12 epitaxial films. We have also observed a giant Faraday rotation of 1-1.10 degree/µm in our optimized films. The measured Faraday rotation value is 1.6 and 50 times larger than that of CeYIG and YIG respectively. A theoretical model has been proposed for Faraday rotation based on density matrix method and an excellent agreement between experiment and theory is found.
STRUCTURAL AND MAGNETO-OPTICAL PROPERTIES OF PULSED LASER DEPOSITED Bi SUBSTITUTED IRON GARNET FILMS
Journal of the Magnetics Society of Japan, 1996
Oriented, highly Bi substituted Dy iron garnet films with perpendicular magnetic anisotropy have been grown by pulsed laser deposition on (111) Ga3GdsOl1, single crystal substrates, The effect of substrate temperature and oxygen pressure on the structure and magneto-optical properties of the films has been investigated. The Bi stoichiometry was found to be sensitive to both substrate temperature and oxygen pressure. The results suggest that at elevated temperatures required to nucleate the garnet phase, the oxygen background pressure must be sufficiently high to incoIpOrate the volatile Ri atoms into the film. Reduced oxygen pressures negatively affect the perpendicular anisotropy.
Thin Solid Films, 2011
Ferrimagnetic bismuth substituted yttrium iron garnet Bi x Y 3 − x Fe 5 O 12 (BiYIG) films with x = 1 and 2 pulsed laser deposited onto (111) Gd 3 Ga 5 O 12 (GGG) substrates were studied using magneto-optical (MO) Kerr spectroscopy in the photon energy range of 1.8-5 eV at both polar and longitudinal magnetizations. The interference at lower photon energies provided the refined film thicknesses ranging between 70 and 200 nm. The films were grown under compressive strain and displayed saturation magnetizations (μ 0 M s ) lower than that of their bulk counterparts due to the presence of nanograins forming BiYIG layers and/or magnetically dead interface layers. The trends in the MO spectra agree with those deduced from the published permittivity tensor data for BiYIG using a transfer matrix model applied to a film (BiYIG)-substrate (GGG) system. Due to the reduced μ 0 M s the predicted amplitudes are typically higher. The agreement was improved using effective medium approach or by incorporating into the model MO passive interface layers. The information on MO activity at longitudinal magnetization in the garnet layers below 100 nm presents interest for MO imaging and magnetophotonic devices. The results suggest that the MO Kerr spectroscopy combined with MO Kerr magnetometry may represent a valuable, cheap and nondestructive tool for the characterization of magnetic garnet films less than 200 nm thick.
Strong enhancement of the Faraday rotation in Ce and Bi comodified epitaxial iron garnet thin films
Applied Physics Letters, 2009
Ce and Bi comodified iron garnet ͑Ce 2.2 Bi 0.8 Fe 5 O 12 ͒ thin films for magneto-optic applications were epitaxially grown on a ͑111͒-oriented Gd 3 Ga 5 O 12 substrate by pulsed laser deposition. We found that epitaxial film quality could be achieved under a low-pressure Ar atmosphere. Surprisingly, our 1 m thick epitaxial films showed a record Faraday rotation as high as 0.55 deg/ m, a value strongly dependent on the concentration of Bi 3+ ions.
Journal of Magnetism and Magnetic Materials, 1996
Polycrystalline thin films of highly Bi substituted Dy iron garnets, [(BixDy3_ x( Fe, Ga)5012 ], with [ 111 ] crystalline orientation perpeladicular to the film plane were grown on (111) Gd3Ga5012, single crystal substrates using pulsed laser deposition technique. In the deposited films, Bi stoichiometry was found to be very sensitive to both substrate temperature a~d oxygen pressure. The Bi volatilisation problem was relieved by depositing in a high background pressure of oxygen. The results demonstrated that high quality garnet films with large magneto-optical (Me) effects and square hysteresis loops could be obtained when the substrate temperature did not exceed 590°C and the oxygen pressure was kept in the neighbourhood of 0.2 mbar. The Me behaviour of these films compared well with predictions based on the fundamental constants of Bi substituted Yttrium Iron Garnet thick films, grown by liquid phase epitaxy. The coercivity could be varied from a few hundred Oe to several kOe by controlling the oxygen pressure and film thickness. from random polycrystalline to highly textured to single crystal. While the production of high quality epitaxial thick films (l_Lm range), with low propagation loss, is essential for development of waveguide devices operating at microwave frequencies, polycrystalline Bi:RIG thin films (nm range) with perpendicular magnetic anisotropy are useful at low frequencies.
Advanced Optical Materials, 2021
Films of polycrystalline terbium iron garnet (TbIG), cerium substituted TbIG (CeTbIG) and bismuth substituted TbIG (BiTbIG) were grown on Si substrates by pulsed laser deposition. The films grow under tensile strain due to thermal mismatch with the Si substrate, resulting in a dominant magnetoelastic anisotropy which, combined with shape anisotropy, leads to in-plane magnetization. TbIG has a compensation temperature of 253 K which is reduced by substitution of Ce and Bi. The Faraday rotation at 1550 nm of the TbIG, Ce0.36TbIG and Bi0.03TbIG films were 5400 600 o /cm, 4500 100 o /cm and 6200 300 o /cm respectively while Ce0.36TbIG and Bi0.03TbIG exhibited lower optical absorption than TbIG, attributed to a reduction in Fe 2+ and Tb 4+ absorption pathways. The high Faraday rotation of the films, and in particular the high magnetooptical figure of merit of the Bi0.03TbIG of 720 o dB-1 at 1550 nm, make these polycrystalline films valuable for applications in integrated photonics.
Physical Review B, 2008
We have studied the influence of the stoichiometry on the structural, magnetic, and magneto-optical properties of bismuth iron garnet ͑Bi 3 Fe 5 O 12 ͒ thin films grown by pulsed laser deposition. Films with different stoichiometries have been obtained by varying the Bi/Fe ratio of the target and the oxygen pressure during deposition. Stoichiometry variations influence the Curie temperature T C by tuning the ͑Fe͒-O-͓Fe͔ geometry: T C increases when the lattice parameter decreases, contrary to what happens in the case of stoichiometric rare-earth iron garnets. The thermal variation of the magnetization, the Faraday rotation, and the Faraday ellipticity have been analyzed in the frame of the Néel two-sublattice magnetization model giving energies of −48 K ͑4.1 meV͒, −29 K ͑2.5 meV͒, and 84 K ͑7.3 meV͒ for the three magnetic exchange integrals j aa , j dd , and j ad , respectively. Magneto-optical spectroscopy linked to compositional analysis by Rutherford backscattering spectroscopy shows that Bi and/or Fe deficiencies also affect the spectral variation ͑between 1.77 and 3.1 eV͒. Our results suggest that bismuth deficiency has an effect on the magneto-optical response of the tetrahedral Fe sublattice, whereas small iron deficiencies affect predominantly the magneto-optical response of the octahedral sublattice.
IEEE Transactions on Magnetics, 2008
Growth and characterization of thin (210)-oriented epitaxial garnet films with Bi and Pr substitutions are reported. The interesting property of these films is the existence of an easy plane of magnetization inclined with respect to the film plane. This property allows for the development of high sensitivity magneto-optic imagers and indicators capable of real time detection of two-dimensional magnetic field patterns. Tailoring of the anisotropy coefficients to achieve the easy magnetization plane and its robustness are discussed. The results of experimental studies of the dependence of the anisotropy properties on the melt composition and growth conditions are reported.
Journal of Physics D-applied Physics, 2001
The series of epitaxial garnet films of general composition Lu3-x-yBixPryFe5- zAlzO12 and Lu3-xBixFe5-y- zScyAlzO12 were grown on (111) oriented GGG (gadolinium gallium garnet) substrates by the liquid phase epitaxy. Their magnetic and magneto-optical properties were studied using both experimental techniques and modelling. All obtained films demonstrated generally a magnetic anisotropy close to the easy-plane type. The Pr-containing films exhibited large negative uniaxial anisotropy and significant cubic anisotropy. The latter causes a distortion of magnetization curves in samples magnetized in a direction normal to the film plane, especially at low temperatures. The large negative uniaxial anisotropy of Pr-substituted iron garnets allows us to increase the saturation field up to 0.5 T at liquid nitrogen temperature. The Sc-doped films displayed small positive uniaxial anisotropy that did not exceed the shape anisotropy. The magnetization curves of these films did not show any distortion due to the cubic anisotropy. The suitability of Pr- and Sc-doped garnets that meet the requirements for indicator layers for magneto-optic visualization at liquid nitrogen temperature is discussed.
Scientific Reports, 2016
Magneto-optical cerium-substituted yttrium iron garnet (Ce:YIG) thin films display Faraday and Kerr rotation (rotation of light polarisation upon transmission and reflection, respectively) as well as a nonreciprocal phase shift due to their non-zero off-diagonal permittivity tensor elements, and also possess low optical absorption in the near-infrared. These properties make Ce:YIG useful in providing nonreciprocal light propagation in integrated photonic circuits, which is essential for accomplishing energy-efficient photonic computation and data transport architectures. In this study, 80 nmthick Ce:YIG films were grown on Gadolinium Gallium Garnet substrates with (100), (110) and (111) orientations using pulsed laser deposition. The films had bulk-like structural and magnetic quality. Faraday and Kerr spectroscopies along with spectroscopic ellipsometry were used to deduce the complete permittivity tensor of the films in the ultraviolet, visible and near-infrared spectral region, and the magneto-optical figure of merit as a function of wavelength was determined. The samples showed the highest IR Faraday rotation reported for thin films of Ce:YIG, which indicates the importance of this material in development of nonreciprocal photonic devices.