Magneto‐Optic Garnet Sensor Films: Preparation, Characterization, Application

Görnert, P.; Lorenz, Andreas; Lindner, Morris; Richert, Hendryk

doi:10.1002/9783527632879.ch14

Cited by 4 publications

(5 citation statements)

References 40 publications

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“…This is important for possible applications mentioned above. So far, classical LPE was applied to grow micrometer-thick samples used for magneto-static microwave devices [47,48] or for magneto-optical imaging systems [49]. The typical shortcomings of the LPE technology making thin-film growth so difficult lie in the fact, that, due to high growth rates, nanometer-thin films were technologically difficult to access.…”

Section: Introductionmentioning

confidence: 99%

Low damping and microstructural perfection of sub-40nm-thin yttrium iron garnet films grown by liquid phase epitaxy

Dubs

Surzhenko

Thomas

et al. 2020

Phys. Rev. Materials

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The field of magnon spintronics is experiencing an increasing interest in the development of solutions for spin-wave-based data transport and processing technologies that are complementary or alternative to modern CMOS architectures. Nanometer-thin yttrium iron garnet (YIG) films have been the gold standard for insulator-based spintronics to date, but a potential process technology that can deliver perfect, homogeneous large-diameter films is still lacking. We report that liquid phase epitaxy (LPE) enables the deposition of nanometer-thin YIG films with low ferromagnetic resonance losses and consistently high magnetic quality down to a thickness of 20 nm. The obtained epitaxial films are characterized by an ideal stoichiometry and perfect film lattices, which show neither significant compositional strain nor geometric mosaicity, but sharp interfaces. Their magneto-static and dynamic behavior is similar to that of single crystalline bulk YIG. We found, that the Gilbert damping coefficient α is independent of the film thickness and close to 1 × 10 -4 , and that together with an inhomogeneous peak-to-peak linewidth broadening of ∆H 0|| = 0.4 G, these values are among the lowest ever reported for YIG films with a thickness smaller than 40 nm. These results suggest, that nanometer-thin LPE films can be used to fabricate nano-and micro-scaled circuits with the required quality for magnonic devices. The LPE technique is easily scalable to YIG sample diameters of several inches.

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Section: Introductionmentioning

confidence: 99%

Low damping and microstructural perfection of sub-40nm-thin yttrium iron garnet films grown by liquid phase epitaxy

Dubs

Surzhenko

Thomas

et al. 2020

Phys. Rev. Materials

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“…It describes a rotation of the plane of polarization that is proportional to the magnetization component along the propagation direction of the light and the length of the path on which the light interacts with the material. An important application of the Faraday effect are magneto-optical indicator films 41 (MOIF), that can be used to image the stray field above a sample. These typically consist of a thin garnet film with inplane anisotropy that is coated with a mirror on one side.…”

Section: Magneto-optical Kerr Effect (Moke) and Faraday Effectmentioning

confidence: 99%

“…The motion of Abrikosov vortices leads to energy dissipation and hence to increased losses that reduce the quality factor of the resonator. The distribution of magnetic flux within the superconducting resonator can be visualized by placing a magneto-optic indicator film (MOIF) 41,86 on top of the resonator. The Faraday effect in the MOIF leads to a rotation of the plane of polarization that is proportional to the magnetic field at the position of the MOIF.…”

Section: A Magnetic Domains In Barium Hexaferritementioning

confidence: 99%

A high-resolution combined scanning laser and widefield polarizing microscope for imaging at temperatures from 4 K to 300 K

Lange¹,

Guénon²,

Lever³

et al. 2017

Review of Scientific Instruments

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Polarized light microscopy, as a contrast-enhancing technique for optically anisotropic materials, is a method well suited for the investigation of a wide variety of effects in solid-state physics, as for example birefringence in crystals or the magneto-optical Kerr effect (MOKE). We present a microscopy setup that combines a widefield microscope and a confocal scanning laser microscope with polarization-sensitive detectors. By using a high numerical aperture objective, a spatial resolution of about 240 nm at a wavelength of 405 nm is achieved. The sample is mounted on a 4 He continuous flow cryostat providing a temperature range between 4 K and 300 K, and electromagnets are used to apply magnetic fields of up to 800 mT with variable in-plane orientation and 20 mT with out-of-plane orientation. Typical applications of the polarizing microscope are the imaging of the in-plane and out-of-plane magnetization via the longitudinal and polar MOKE, imaging of magnetic flux structures in superconductors covered with a magneto-optical indicator film via Faraday effect or imaging of structural features, such as twin-walls in tetragonal SrTiO 3 . The scanning laser microscope furthermore offers the possibility to gain local information on electric transport properties of a sample by detecting the beam-induced voltage change across a current-biased sample. This combination of magnetic, structural and electric imaging capabilities makes the microscope a viable tool for research in the fields of oxide electronics, spintronics, magnetism and superconductivity.

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“…Contrary to its parent structures such as, for example, the well-known yttrium iron garnet (YIG) 2 , this material can only be synthesized in thin-film form using non-equilibrium growth techniques 3 . Nevertheless the growth effort worths the price since ferrimagnetic bismuth iron garnet shows relatively high magnetization of 1.27x10 5 A/m at 300 K and magnetic ordering temperature from 650 K to 700 K, depending on Bi content and film thicknesses 3,4 . Moreover, BIG giant Faraday rotation effect makes this material a suitable candidate for fast magneto-optical sensors 5 , optical isolators 6 and second harmonic generation 7 .…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless the growth effort worths the price since ferrimagnetic bismuth iron garnet shows relatively high magnetization of 1.27x10 5 A/m at 300 K and magnetic ordering temperature from 650 K to 700 K, depending on Bi content and film thicknesses 3,4 . Moreover, BIG giant Faraday rotation effect makes this material a suitable candidate for fast magneto-optical sensors 5 , optical isolators 6 and second harmonic generation 7 . Despite the significant technological interest, the structural and electronic properties of BIG thin films remains debated.…”

Section: Introductionmentioning

confidence: 99%

Bismuth iron garnet: Ab initio study of electronic properties

et al. 2019

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Bismuth iron garnet (BIG), i.e. Bi3Fe5O12, is a strong ferrimagnet that also possess outstanding magneto-optical properties such as the largest known Faraday rotation. These properties are related with the distribution of magnetic moments on octahedral and tetrahedral sites, the presence of spin gaps in the density of state and a strong spin-orbit coupling. In this work, first-principles ab initio calculations are performed to study the structural, electronic and magnetic properties of BIG using Density Functional Theory with Hubbard+U (DFT+U ) correction including spin-orbit coupling and HSE06 hybrid functional. We found that the presence of spin gaps in the electronic structure results from the interplay between exchange and correlation effects and the crystal field strengths for tetrahedral and octahedral iron sublattices. The DFT+U treatment tends to close the spin-gaps for larger U due to over-localization effects, notably in the octahedral site. On the other hand, the hybrid functional confirms the occurrences of three spin gaps in the iron states of the conduction band as expected from optical measurements. A strong exchange splitting at the top of the valence bands associated with a lone-pair type mixture of O p and Bi s,p states is also obtained. Similar exchange splitting was not previously observed for other iron based garnets, such as for yttrium iron garnet. It follows that hole doping, as obtained by Ca substitution at Bi sites, results in a full spin polarized density at the Fermi energy. This work helps to shed more light on the theoretical comprehension of the properties of BIG and opens the route towards the use of advanced Many Body calculations to predict the magneto-optical coupling effects in BIG in a direct comparison with the experimental measurements.

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Magneto‐Optic Garnet Sensor Films: Preparation, Characterization, Application

Cited by 4 publications

References 40 publications

Low damping and microstructural perfection of sub-40nm-thin yttrium iron garnet films grown by liquid phase epitaxy

Low damping and microstructural perfection of sub-40nm-thin yttrium iron garnet films grown by liquid phase epitaxy

A high-resolution combined scanning laser and widefield polarizing microscope for imaging at temperatures from 4 K to 300 K

Bismuth iron garnet: Ab initio study of electronic properties

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