Terbium Iron Garnet Research Articles

Elastic constants of single crystal terbium iron garnet

Elastic constants of single crystal terbium iron garnet

Temperature and high magnetic field dependence of the Faraday rotation in the terbium iron garnet

The Faraday rotation of terbium iron garnet at 1.15 03BC wavelength is presented. The experimental results have been obtained along the [111] easy direction both in low d.c. field 20 kOe as a function of temperature between 4.2 and 300 K and at room temperature as a function of the applied field (up to 1 200 kOe). The results are analysed in terms of magnetic and electric dipole contributions from the three magnetic sublattices. The Fe3+ contributions are considered to have the same values as in YIG and the total Tb3+ contributions are obtained. The contribution of the magnetic dipole transitions of the R.E. has been calculated when the influence of the crystalline field effect on the Lande factor is taken into account; the electric dipole contribution is found to be strongly temperature and magnetic field dependent. LE JOURNAL DE PHYSIQUE TOME 40, SEPTEMBRE 1979,

Magnetic birefringence and its relation to the sublattices in rare-earth iron garnets

A phenomenological analysis of the magnetic linear birefringence (MLB) in ferrimagnets is given in terms of a two-sublattice model (TSM). MLB has been studied in yttrium iron garnet (YIG), in gallium substituted YIG and in terbium iron garnet (TbIG) in a temperature range 80–450K in magnetic fields up to 30kG at the wavelength 1.15μ m. It has been proven that in YIG in the whole temperature range TSM is valid. In TbIG deviations from TSM has been found at low temperatures. These deviations have been related to the changes of the local symmetry of magnetic ions.

X-ray topographic study of magnetic domains in a single crystal of terbium iron garnet between 300 and 4.2 K

(110) slices of TbIG have been studied by means of x-ray transmission topography between room temperature and liquid-helium temperature. This work gives most of the results concerning the variations of the domain structure with the temperature. The room-temperature structure is limited by a rectangular array of 71° and 109° walls separating domains where the magnetization lies in the plane of the sample. It corresponds to the equilibrium configuration in a perfect crystal. The domain density increases sharply when the temperature is lowered, and a preferential occurrence has been observed for the (1̄10) 71° walls at low temperature. The wall contrast, due to magnetostrictive stresses, is also temperature sensitive. In order to understand these experimental evidences, the surface energies of the 71° and 109° walls have been calculated, using a classical model of the Bloch wall structure. This calculation shows the predominant importance, at low temperatures, of the K2 term and the additional magnetostrictive contribution to the development of the magnetocrystalline anisotropy energy. It would certainly be of great interest from a physical point of view to start from the atomic model of the magnetic structure in order to understand the internal structure of the magnetic domain walls in the garnets at low temperature.

Neutron scattering length of terbium structure refinement and magnetic moments of terbium iron garnet

The neutron scattering length of terbium was redetermined from powder data on terbium iron garnet (TbIG) and TbO 2 by the profile analysis technique. The mean value obtained is b ( Tb) = 0.735(10) x 10 −12 cm. Furthermore the positional and thermal parameters of TbIG have been refined from single crystal X-ray and neutron powder data. The results from both experiments agree well. The X-ray data from a sphere of diameter φ = 282 μm were collected by Mo Kα radiation. The refinement was carried out including an extinction parameter which was also applied to correct for anomalous transmission. The powder data were treated by the profile analysis technique where the structural parameters and the magnetic moments were refined simultaneously. Two slightly different form factor curves were applied for Fe 3+ in the crystallographic sites. The magnetic moments for the iron ions were found to be μ = 3.69(10) μ B for the octahedral and 3.65(10) μ B for the tetrahedral site at room temperature. The moment for terbium is μ = 1.15(09) μ B and the whole magnetisation for one formula unit is 0.12(0.40) μ B . The observed moments of Fe 3+ are considerably reduced as compared to the free ion spin only value which was calculated from a Brillouin function for S = 5 2 to be 4.34 μ B at 300 K.

X-ray powder diffraction at low temperature applied to the determination of magnetoelastic properties in terbium iron garnet

An x-ray powder diffraction apparatus has been built to perform experiments between 2.6 and 350 K. The experimental procedure and the data analysis allow the measurement of small lattice distortions and very small parameter variations with a good accuracy. Relative variations of the crystal parameters of terbium iron garnet, with an accuracy up to 10−5, have been observed at low temperature. A very small lattice distortion has been determined: TbIG becomes rhombohedral below 100 K; at 4.2 K the rhombohedral angle of the distorted cell is αR=89°52′30″, while the cell side is slightly contracted. A noncollinear spin arrangement, an anomalous thermal expansion (Δa=28×10−4 at 4.2 K), and a rhombohedral distortion (β=90°−αR=7′30″ at 4.2 K) appear simultaneously at about 45 K. These phenomena are to be connected with a very large magnetostriction (λIII=2400×10−6 at 4.2 K).

Far-infrared spectra of dysprosium and terbium iron garnet

Far-infrared transmission spectra of dysprosium and terbium iron garnet were measured between 10 and 150 cm−1 at temperatures less than 20 K by Fourier-transform spectroscopy. The temperature and magnetic-field dependence of the transmission spectrum of dysprosium iron garnet was also observed. For dysprosium iron garnet, absorption lines at 22.6, 59.5, 44.0, and 65 cm−1 were identified as low-lying electronic levels. Magnetic resonances at 13.5, 17.0, and 28.0 cm−1 and phonon absorption lines at 81, 107, 112, and 145 cm−1 were found. For terbium iron garnet, two electronic lines at 36 and 68.5 cm−1 and four phonon lines at 80.5, 108, 112, and 145 cm−1 were found.

X-ray topographic studies of magnetic domain patterns in terbium iron garnet

physica status solidi (a)Volume 20, Issue 1 p. K1-K4 Short Note X-ray topographic studies of magnetic domain patterns in terbium iron garnet A. Mathiot, A. Mathiot Laboratoire de Minéralogie-Cristallographie, associé au C.N.R.S., Université de Paris VISearch for more papers by this authorJ. F. Petroff, J. F. Petroff Laboratoire de Minéralogie-Cristallographie, associé au C.N.R.S., Université de Paris VISearch for more papers by this authorY. Bernard, Y. Bernard Laboratoire de Minéralogie-Cristallographie, associé au C.N.R.S., Université de Paris VISearch for more papers by this author A. Mathiot, A. Mathiot Laboratoire de Minéralogie-Cristallographie, associé au C.N.R.S., Université de Paris VISearch for more papers by this authorJ. F. Petroff, J. F. Petroff Laboratoire de Minéralogie-Cristallographie, associé au C.N.R.S., Université de Paris VISearch for more papers by this authorY. Bernard, Y. Bernard Laboratoire de Minéralogie-Cristallographie, associé au C.N.R.S., Université de Paris VISearch for more papers by this author First published: 16 November 1973 https://doi.org/10.1002/pssa.2210200144Citations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume20, Issue116 November 1973Pages K1-K4 RelatedInformation

Faraday Rotation in Rare-Earth Iron Garnets

The Faraday rotation of yttrium, gadonlinium, and terbium iron garnets at 1.15 \ensuremath{\mu} is presented as a function of temperature between 100 and 450\ifmmode^\circ\else\textdegree\fi{}K. The rotation is analyzed in terms of electric and magnetic dipole contributions from the various magnetic sublattices (${\mathrm{Fe}}^{3+}$ octahedral, ${\mathrm{Fe}}^{3+}$ tetrahedral, R${\mathrm{E}}^{3+}$), and the contributions are separated by a least-squares fit to magnetization data. The similarities and differences in the electric dipole contributions are discussed, and it is suggested that charge-transfer processes are important. The effect of a knowledge of the electric dipole contributions at 1.15 \ensuremath{\mu} on published results at longer wavelengths is investigated, and deductions of $g$ factors in this region are shown to be probably in error. In an Appendix, theoretical derivations are given for the form of the electric dipole rotation due to magnetic ions in various circumstances.

Long-Wavelength Collective Excitations in Ferromagnetic Insulators. I. Strong Coupling of Acoustic Modes to Spin Wave Modes

Investigations have been made of long-wavelength collective lattice vibrations and long-wavelength spin wave modes in ferromagnetic insulators such as the rare-earth iron garnets. These materials have many different sites for the rare earth ions and generally have unquenched orbital moments. In this paper both theoretical and experimental work are reported with the main consideration being strong coupling effects between acoustic and spin wave modes. The strong coupling produces a field dependence of the resonant frequency and acoustic $Q$ of long-wavelength acoustic modes in saturated (i.e., single domain) samples. The sample shapes employed are spheres and thin disks. Satisfactory agreement is obtained between theory and experiment concerning the field dependences, rare earth concentration dependences, and correlation of acoustic effects with spin resonance quantities, such as linewidth. Also from these results values are obtained of the cubic magnetoelastic coupling constants ${B}_{1}$ and ${B}_{2}$ for terbium and europium iron garnets.