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S. I. Yushchuk 《Technical Physics》1999,44(12):1454-1456
The layered structure of yttrium iron garnet films, ranging in thickness from 0.7 to 4.1 μm, grown epitaxially on single-crystal
gallium-gadolinium garnet substrates, was investigated by x-ray spectral microanalysis. The ferrite films were chemically
etched layer by layer in a mixture of orthophosphoric and sulfuric acids at T=353–423 K. It was established that the chemical composition of the films varies over the thickness because of the nonuniform
distribution of gadolinium, gallium, lead, and platinum ions; the film-substrate transitional layer and the surface layer
of the film differ most greatly with respect to the composition and magnetic properties. It was shown that the thickness of
the transitional layers and their negative effect on the magnetic characteristics of ferrite films decrease appreciably if
at the time of immersion of the substrate and pulling of epitaxial structure out of the fluxed solution the substrate holder
together with a special mixer rotate at a rate of 50 rpm and the pulling velocity is 20 cm/min.
Zh. Tekh. Fiz. 69, 62–64 (December 1999) 相似文献
3.
E. Popova N. Keller F. Jomard L. Thomas M.-C. Brianso F. Gendron M. Guyot M. Tessier 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(1):69-74
Magnetic exchange coupling has been observed for ultrathin films of yttrium iron garnet (Y3Fe5O12 or YIG). Single-crystalline YIG films were prepared on yttrium aluminium garnet (Y3Al5O12 or YAG) substrates by pulsed laser deposition. (111) and (110) oriented substrates were used. Film thicknesses were varied
from 180 ? to 4600 ?. Epitaxial growth of YIG on YAG was obtained in spite of the lattice mismatch of 3%. Magnetic hysteresis
loops recorded for ultrathin YIG films have a “bee-waist” shape and show a coupling between two different magnetic phases.
The first phase is magnetically soft YIG. A composition study by secondary ion mass spectroscopy shows the second phase to
be Y3Fe5-xAlxO12 due to the interdiffusion of Fe and Al at the film/substrate interface. This compound is known to be magnetically harder
and to have weaker magnetization than YIG. The coupling of the two phases leads to a hysteresis loop displacement at low temperatures.
This displacement varies differently with film thickness for two substrate orientations. Assuming an interfacial coupling,
the maximal interaction energy is estimated to be about 0.17 erg/cm2 at 5 K for (111) oriented sample.
Received 3 June 2002 / Received in final form 7 October 2002 Published online 27 January 2003
RID="a"
ID="a"Presently at LPM, Université H. Poincaré, BP 239, 54506 Vandœuvre-lès-Nancy e-mail: popova@lpm.u-nancy.fr 相似文献
4.
V. F. Shkar’ E. I. Nikolaev V. N. Sayapin A. I. Linnik V. P. Denysenkov A. M. Grishin S. I. Khartsev 《Physics of the Solid State》2005,47(6):1107-1110
Ferromagnetic resonance (FMR) and vibrating-sample magnetometer techniques were used to study the nature of the structural characteristics of yttrium iron garnet films deposited through either liquid phase epitaxy or laser evaporation on a (111)-oriented gallium gadolinium garnet substrate. It was proved that, based on the experimentally observed cubic magnetic anisotropy, deposited films should be considered to be single crystals. However, the absence of the FMR domain branch in a nonsaturated film and the shape of the magnetization curve indicate that a deposited film when demagnetized does not have a domain structure, as would be expected for a single-crystal film. According to the model proposed, a deposited film consists of close-packed single-crystal fragments with equal crystallographic orientation, the boundaries between which are in a partially atomically disordered state. As a result, such a film is both locally and macroscopically anisotropic, like a continuous single crystal. This film can split into domains only within a fragment (as is the case in a magnetic granular polycrystal); however, this does not happen, because the linear dimensions of a submicroscopic fragment are smaller than the equilibrium domain width. 相似文献
5.
In ferromagnetic-resonance experiments on yttrium-iron-garnet films, a signal edge has been observed whose characteristics are consistent with its interpretation as the bottom of the spin-wave band. 相似文献
6.
The four-magnon instability of magnetostatic surface waves (MSSWs) in yttrium iron garnet epitaxial films is investigated
experimentally. It is shown that four-magnon instability for MSSWs with wave numbers 30–600 cm−1 is a decay instability and develops for values of the wave magnetization close to the threshold level for second-order parametric
instability of a homogeneous transverse pump wave. When the supercriticality of the MSSW power is 15–20 dB, the generated
parametric spin waves themselves become unstable with respect to the four-magnon interaction, so that kinetic instability
develops in the film. It is shown that the pump signal transmitted through the signal and the length of the “nonlinear” part
of the film, where a MSSW is capable of exciting parametric spin waves, increase as the pump power is increased.
Fiz. Tverd. Tela (St. Petersburg) 38, 330–338 (February 1997) 相似文献
7.
Shuyao Chen 《中国物理 B》2022,31(4):48503-048503
Yttrium iron garnet (YIG) films possessing both perpendicular magnetic anisotropy (PMA) and low damping would serve as ideal candidates for high-speed energy-efficient spintronic and magnonic devices. However, it is still challenging to achieve PMA in YIG films thicker than 20 nm, which is a major bottleneck for their development. In this work, we demonstrate that this problem can be solved by using substrates with moderate lattice mismatch with YIG so as to suppress the excessive strain-induced stress release as increasing the YIG thickness. After carefully optimizing the growth and annealing conditions, we have achieved out-of-plane spontaneous magnetization in YIG films grown on sGGG substrates, even when they are as thick as 50 nm. Furthermore, ferromagnetic resonance and spin pumping induced inverse spin Hall effect measurements further verify the good spin transparency at the surface of our YIG films. 相似文献
8.
We investigate the stability of the recently discovered room-temperature Bose-Einstein condensate (BEC) of magnons in yttrium iron garnet films. We show that magnon-magnon interactions depend strongly on the external field orientation, and that the BEC in current experiments is actually metastable-it only survives because of finite-size effects, and because the BEC density is very low. On the other hand a strong field applied perpendicular to the sample plane leads to a repulsive magnon-magnon interaction; we predict that a high-density room-temperature magnon BEC should then form in this perpendicular field geometry. 相似文献
9.
Mössbauer spectroscopy of a silicon substituted YIG containing 0.3 Si4+ per formula unit has shown that a spin reorientation, from [111] to [100], occurs between 265 and 80 K. The transitions occur by way of the magnetic space groups . The broad spin reorientation is mainly a consequence of the persistence of a nonuniform distribution of Fe2+ ions over the octahedral sites. 相似文献
10.
Amplification of a weak-signal spin wave by a strong pump spin wave propagating in an yttrium iron garnet film is observed
for the first time. A theoretical explanation of the amplification phenomenon is suggested on the basis of the four-wave parametric
processes.
Pis’ma Zh. éksp. Teor. Fiz. 64, No. 3, 160–165 (10 August 1996)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
11.
Luminescence spectra and photoluminescence excitation spectra of Y2O3:Bi and Y3Al5O12:Bi thin films were investigated. Luminescence was stimulated by the emission from two types of centers that were associated
with the substitution of Bi3+ for Y3+ in sites of the crystal lattice of Y2O3 (Y3Al5O12) with point symmetries C2 and C3i (D2 and C3i). The emission of Bi3+ in the site with point symmetry C3i causes blue luminescence in both Y2O3:Bi and Y3Al5O12:Bi films with maxima at 3.03 eV and 3.15 eV, respectively, that is related to the 3P1-1S0 transition. The emission of Bi3+ in the site with point symmetry C2 gives green luminescence in Y2O3:Bi with the maximum at 2.40 eV that is also related to the 3P1-1S0 transition. The emission of Bi3+ in the site with point symmetry D2 leads to ultraviolet luminescence in Y3Al5O12:Bi with the maximum at 3.75 eV that corresponds to the 3P1-1S0 transition. The red luminescence band with the maximum at 1.85 eV in Y2O3:Bi is due to the presence of structural defects.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 2, pp. 202–207, March–April, 2008. 相似文献
12.
A. Rogalev F. Wilhelm A. Yaresko M.V. Indenbom 《Journal of magnetism and magnetic materials》2009,321(23):3945-3962
X-ray magnetic circular dichroism (XMCD) was used to probe the existence of induced magnetic moments in yttrium iron garnet (YIG) films in which yttrium is partly substituted with lanthanum, lutetium or bismuth. Spin polarization of the 4d states of yttrium and of the 5d states of lanthanum or lutetium was clearly demonstrated. Angular momentum resolved d-DOS of yttrium and lanthanun was shown to be split by the crystal field, the two resolved substructures having opposite magnetic polarization. The existence of a weak orbital moment involving the 6p states of bismuth was definitely established with the detection of a small XMCD signal at the Bi M1-edge. Difference spectra also enhanced the visibility of subtle changes in the Fe K-edge XMCD spectra of YIG and {Y, Bi}IG films. Weak natural X-ray linear dichroism signatures were systematically observed with all iron garnet films and with a bulk YIG single crystal cut parallel to the (1 1 1) plane: this proved that, at room temperature, the crystal cannot satisfy all requirements of perfect cubic symmetry (space group: ), crystal distortions preserving at best trigonal symmetry ( or R3m). For the first time, a very weak X-ray magnetic linear dichroism (XMLD) was also measured in the iron K-edge pre-peak of YIG and revealed the presence of a tiny electric quadrupole moment in the ground-state charge distribution of iron atoms. Band-structure calculations carried out with fully relativistic LMTO-LSDA methods support our interpretation that ferrimagnetically coupled spins at the iron sites induce a spin polarization of the yttrium d-DOS and reproduce the observed crystal field splitting of the XMCD signal. 相似文献
13.
C. J. M. Denissen 《Hyperfine Interactions》1990,56(1-4):1577-1585
57Fe-enriched, epitaxial Y3Fe5O12 films have been implanted with 50 keV and 100 keV neon ions with a dose of 4·1014Ne+/cm2. Depth-selective conversion electron Mössbauer spectroscopy has been performed at 300 K and 40 K. The results show that the 50 keV-implanted sample can be interpreted as an amorphous layer on top of an almost unperturbed YIG layer. In the 100 keV-implanted film a buried amorphous layer is observed. 相似文献
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Yongxue He Peng He Soack Dae Yoon P.V. Parimi F.J. Rachford V.G. Harris C. Vittoria 《Journal of magnetism and magnetic materials》2007
A magnetic field tunable, broadband, low-loss, negative refractive index metamaterial is fabricated using yttrium iron garnet (YIG) and a periodic array of copper wires. The tunability is demonstrated from 18 to 23 GHz under an applied magnetic field with a figure of merit of 4.2 GHz/kOe. The tuning bandwidth is measured to be 5 GHz compared to 0.9 GHz for fixed field. We measure a minimum insertion loss of 4 dB (or 5.7 dB/cm) at 22.3 GHz. The measured negative refractive index bandwidth is 0.9 GHz compared to 0.5 GHz calculated by the transfer function matrix theory and 1 GHz calculated by finite element simulation. 相似文献
16.
Magnetic bubbles have again become a subject of significant attention following the experimental observation of topologically nontrivial magnetic skyrmions. In recent work, tailoring the shape of the bubbles is considered a key factor for their dynamics in spintronic devices. In addition to the reported circular, elliptical, and square bubbles, here we observe triangular bubble domains in bismuth-doped yttrium iron garnet(Bi-YIG) using Kerr microscopy. The bubble domains evolve from discrete cir... 相似文献
17.
Samuel M. Myers Horst Meyer
J. P. Remeika
《Journal of Physics and Chemistry of Solids》1969,30(12):2687-2692Pulse measurements of T1 for 57Fe nuclei in very pure, single crystals of YIG are reported. The temperature was varied from 2° to 292°K, and the externally applied field ranged from 0 to 6000 Oe. The temperature variation of T1 is quite strong, being three orders of magnitude in the range 2°–40°K. At constant temperature, T1 changed approximately one order of magnitude between saturation field and 6000 Oe. The data are compared with the results of a calculation by Beeman and Pincus, in which a second-order Raman process and the three-magnon process are assumed to predominate below 50°K. Agreement is only qualitative, the experimental values of T1 being larger than predicted. At 4.2°K in zero field, it is found that a polycrystalline sample containing particles of ≈ 5 × 10−4 cm dia. has a value of 1/T1 which is some two orders of magnitude larger than for a macroscopic crystal. The presence of a relaxation mechanism associated with surface effects is suggested. 相似文献
18.
F. Schreiber M. Hoffmann O. von Geisau J. Pelzl 《Applied Physics A: Materials Science & Processing》1993,57(6):545-551
The conventional and photothermally modulated (PM) ferromagnetic resonance (FMR) of magnetostatic modes (MSM) in yttrium iron garnet (YIG) films have been investigated as a function of temperature. Approaching the ferrimagnetic transition at T
c=560 K a strong enhancement of the PM-FMR signal amplitude is observed which is accompanied by a change of the signal shape. The observations are discussed in the framework of a model that takes into account the temperature derivatives of those quantities that contribute to the high-frequency susceptibility. At temperatures still below T
c a paramagnetic line emerges. The MSM disappear in a state of finite magnetization which is explained on the basis of damping of the MSM being important in the vicinity of the magnetic phase transition. Additionally, frequency and power dependent measurements are presented and the imaging ability of PM-FMR is demonstrated. 相似文献
19.
The self-generation of single, fundamental, stable, spin-wave-envelope black and gray dark solitons has been realized for the first time. These solitons were generated from microwave magnetostatic surface waves (MSSWs) propagated in an in-plane magnetized yttrium iron garnet film MSSW delay line in a resonant ring. These fundamental dark solitons were made possible by a new and general filtering technique for a high gain nonlinear resonant ring. The amplitude and phase profiles together with the power spectra of the self-generated microwave pulses confirm their fundamental dark soliton nature. 相似文献
20.
Brillouin scattering measurements on yttrium iron garnet (YIG) have revealed the scattering due to thermal acoustic magnons. The intensity and frequency shift of the magnon peaks as a function of applied magnetic field and incident light wavelength have been investigated and are discussed here within the framework of a simple light scattering theory. 相似文献