Features of Optical Anisotropy of Terbium Iron Garnet

2013 ◽  
Vol 543 ◽  
pp. 364-367 ◽  
Author(s):  
Natalia Tsidaeva ◽  
Viktorija Abaeva ◽  
Elena Enaldieva ◽  
Tamerlan T. Magkoev ◽  
Anatolij Turiev ◽  
...  
Keyword(s):  
Rare Earth ◽  
Tetrahedral Site ◽  
Recording Media ◽  
Magnetic Recording Media ◽  
Iron Garnets ◽  
Wide Range ◽  
Dodecahedral Site ◽  
Cubic System ◽  
Packed Structure ◽  
Iron Garnet

Rare earth iron garnets with narrow ferromagnetic resonance linewidths, very low hysteresis losses, and excellent dielectric properties have been widely applied in microwave devices in a wide range of frequencies (1100 GHz), magnetooptical transducers and typically employed as magnetic recording media [1-1. The rare earth iron garnets which can be described by chemical unit formulaRE3Fe5O12belong to cubic system with space groupIa3̄d, whose cell contains eightRE3Fe5O12molecules and crystal lattice contains three crystallographic sites, dodecahedral site 24c{RE3+}, octahedral site 16a[Fe3+] and tetrahedral site 24d(Fe3+). The garnet in fact does not allow distortion to lower symmetry owing to its non-efficiently packed structure, which makes iron garnet structure become unstable with increasing rare earth ionic radius.

Glycothermal synthesis of rare earth iron garnets

1998 ◽  
Vol 13 (4) ◽  
pp. 856-860 ◽  
Author(s):  
Masashi Inoue ◽  
Toshihiro Nishikawa ◽  
Tomoyuki Inui
Keyword(s):  
Rare Earth ◽  
Yttrium Aluminum Garnet ◽  
Hydrothermal Reaction ◽  
The Other ◽  
Spontaneous Nucleation ◽  
Iron Garnets ◽  
Yttrium Aluminum ◽  
Ionic Size ◽  
Two Phases ◽  
Iron Garnet

The reactions of rare earth (RE) acetates with iron acetylacetonate in 1,4-butanediol at 300 °C (glycothermal reaction) yielded two novel phases depending on the ionic size of the RE element: one was obtained for Er-Lu and the other for Tb and Dy. The former phase was hexagonal REFeO3, while the latter phase has not been identified. The reaction of Y or Ho acetate yielded the mixture of these two phases. When the reactions were carried out in the presence of seed crystals of yttrium aluminum garnet (Y3Al5O12), these phases were not formed but RE iron garnet (RE3Fe5O12) grew on the seed, which suggests that spontaneous nucleation of RE iron garnet does not occur, but crystal growth proceeds easily under the glycothermal conditions. Hydrothermal reaction of the same starting materials yielded a mixture of Fe2O3 and an amorphous RE phase.

scholarly journals Hydrothermal Synthesis of Various Magnetic Properties of Controlled Micro/Nanostructured Powders and Films of Rare-Earth Iron Garnet

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 972
Author(s):  
Natalia Tsidaeva ◽  
Ahsarbek Nakusov ◽  
Spartak Khaimanov ◽  
Wei Wang
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Hysteresis Loops ◽  
Structural Features ◽  
Nano Particles ◽  
Iron Garnets ◽  
Size Of Particles ◽  
Iron Garnet ◽  
Nanostructured Powders ◽  
The Rare Earth

In this study, the synthesis and magnetic properties of the rare-earth iron garnets Sm3Fe5O12, Pr3Fe5O12, and Er3Fe5O12 (in the form of powders and thin films) are reported. According to the composition, shape, and size of particles, the optimal precipitant for the synthesis of Sm3Fe5O12, Pr3Fe5O12, and Er3Fe5O12 films is an aqueous solution. The parameters for the synthesis of powders and films of the rare-earth iron garnets with micro- and nano-particles have been investigated and selected. The magnetic properties of these materials were studied; field dependencies of the magnetic moment (hysteresis loops) of nanostructured powders of iron garnets of samarium, praseodymium, and erbium in the range of +20 kOe to −20 kOe were obtained. The structural features of the Al2O3 substrate on which the films were formed are also shown.

scholarly journals Flexoelectric nanodomains in rare-earth iron garnet thin films under strain gradient

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Hiroyasu Yamahara ◽  
Bin Feng ◽  
Munetoshi Seki ◽  
Masaki Adachi ◽  
Md Shamim Sarker ◽  
...  
Keyword(s):  
Thin Films ◽  
Rare Earth ◽  
Strain Gradient ◽  
Magnetic Circular Dichroism ◽  
Dielectric Materials ◽  
Dielectric Polarization ◽  
Iron Garnets ◽  
Scanning Transmission ◽  
Out Of Plane ◽  
Iron Garnet

AbstractFlexoelectricity is a universal property associated with dielectric materials, wherein they exhibit remanent polarization induced by strain gradient. Rare-earth iron garnets, R3Fe5O12, are ferrimagnetic insulators with useful magnetic properties. However, they are unlikely to show remanent dielectric polarization because of their centrosymmetric structure. Here, to induce flexoelectricity, we investigate various rare-earth iron-garnet thin films deposited on lattice-mismatched substrates. Atomic-resolution scanning transmission electron microscopy demonstrates the presence of 15 nm-thick strain gradients in Sm3Fe5O12 films between epitaxially strained tetragonal and relaxed cubic structures. Furthermore, negatively polarized nanodomains are imaged by scanning nonlinear dielectric microscopy. It suggests a generation of flexoelectricity, where the polarization points down toward the substrate in the out-of-plane direction. X-ray magnetic circular dichroism demonstrates hysteresis with a large coercive field originating from the strain-gradient layer. We believe that our study will pave the way for achieving dielectric polarization even in nonpolar centrosymmetric materials by strain-gradient engineering.

Synthesis of Magnetic Nanoparticles by Sputtering

2006 ◽  
Vol 980 ◽  
Author(s):  
Mai Miyata ◽  
Kyosuke Kishida ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Gas Flow ◽  
Annealing Temperature ◽  
Gas Pressure ◽  
Fept Nanoparticles ◽  
Recording Media ◽  
Magnetic Recording Media ◽  
Gas Flow Rate ◽  
Annealing Furnace ◽  
Wide Range ◽  
Co Nanoparticles

AbstractThe influence of experimental condition on morphology of FePt and Sm-Co nanoparticles synthesized by sputtering in a relatively high gas pressure has been studied. The sputtering apparatus is equipped with an annealing furnace that enables pre-deposition annealing of the nanoparticles. The effect of the annealing temperature on the ordering to the L10 FePt nanoparticles was also investigated. The morphology of the particles depends on a gas pressure and gas flow rate, but the sensitivity to experimental condition differs between FePt and Sm-Co. The morphology and domain structure of FePt nanoparticle are relatively the same in a wide range of experimental condition, whereas those of Sm-Co nanoparticle are significantly changed by variation of a gas pressure. FePt nanoparticles annealed in the annealing furnace prior to their deposition onto the substrate have the ordered L10 phase, which has an advantage for producing a magnetic recording media.

Crystallization of barium hexaferrite

1992 ◽  
Vol 50 (1) ◽  
pp. 362-363
Author(s):  
Chung-kook Lee ◽  
Yolande Berta ◽  
Robert F. Speyer
Keyword(s):  
Size Distribution ◽  
Raw Materials ◽  
Barium Hexaferrite ◽  
Recording Media ◽  
Magnetic Recording Media ◽  
Promising Candidate ◽  
Crystallization Method ◽  
Temperature Heat ◽  
High Density Magnetic Recording ◽  
Temperature Heat Treatment

Barium hexaferrite (BaFe12O19) is a promising candidate for high density magnetic recording media due to its superior magnetic properties. For particulate recording media, nano-sized single crystalline powders with a narrow size distribution are a primary application requirement. The glass-crystallization method is preferred because of the controllability of crystallization kinetics, hence, particle size and size distribution. A disadvantage of this method is the need to melt raw materials at high temperatures with non-reactive crucibles, e.g. platinum. However, in this work, we have shown that crystal growth of barium hexaferrite occurred during low temperature heat treatment of raw batches.

Structural Investigation of Iron Particles Used for Magnetic Recording Media

1980 ◽  
Vol 38 ◽  
pp. 406-407
Author(s):  
Alfred Baltz
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Structural Investigation ◽  
Magnetic Interaction ◽  
Recording Media ◽  
Magnetic Recording Media ◽  
Recording Medium ◽  
Iron Particles ◽  
Transmission Electron

As part of a program to develop iron particles for next generation recording disk medium, their structural properties were investigated using transmission electron microscopy and electron diffraction. Iron particles are a more desirable recording medium than iron oxide, the most widely used material in disk manufacturing, because they offer a higher magnetic output and a higher coercive force. The particles were prepared by a method described elsewhere. Because of their strong magnetic interaction, a method had to be developed to separate the particles on the electron microscope grids.

Advances in magnetic films of epsilon-iron oxide toward next-generation high-density recording media

2021 ◽  
Author(s):  
Hiroko Tokoro ◽  
Asuka Namai ◽  
Shin-ichi Ohkoshi
Keyword(s):  
Iron Oxide ◽  
Magnetic Films ◽  
High Density ◽  
Recording Media ◽  
Next Generation ◽  
Magnetic Recording Media ◽  
Film Performance ◽  
High Density Recording ◽  
Recent Developments ◽  
High Density Magnetic Recording

Recent developments in magnetic films composed of epsilon-iron oxide are introduced. The film performance is studied and improved toward the next-generation of high-density magnetic recording media.

scholarly journals Ultrafast measurements of the interfacial spin Seebeck effect in Au and rare-earth iron-garnet bilayers

2021 ◽  
Vol 5 (7) ◽  
Author(s):  
Víctor H. Ortiz ◽  
Michael J. Gomez ◽  
Yawen Liu ◽  
Mohammed Aldosary ◽  
Jing Shi ◽  
...  
Keyword(s):  
Rare Earth ◽  
Seebeck Effect ◽  
Ultrafast Measurements ◽  
Spin Seebeck Effect ◽  
Iron Garnet
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