Magnetic resonance and self-sustained oscillations in an iron-yttrium garnet film in a vortex state

Much progress in nuclear magnetic resonance microscope has been made in the last few years as a result of improved instrumentation and techniques being made available through basic research in magnetic resonance imaging (MRI) technologies for medicine. Nuclear magnetic resonance (NMR) was first observed in the hydrogen nucleus in water by Bloch, Purcell and Pound over 40 years ago. Today, in medicine, virtually all commercial MRI scans are made of water bound in tissue. This is also true for NMR microscopy, which has focussed mainly on biological applications. The reason water is the favored molecule for NMR is because water is,the most abundant molecule in biology. It is also the most NMR sensitive having the largest nuclear magnetic moment and having reasonable room temperature relaxation times (from 10 ms to 3 sec). The contrast seen in magnetic resonance images is due mostly to distribution of water relaxation times in sample which are extremely sensitive to the local environment.

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Novel magneto-optical recording materials: Bi-substituted garnet films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100088191 ◽

1991 ◽

Vol 49 ◽

pp. 776-777

Author(s):

Takao Suzuki ◽

Hossein Nuri

Keyword(s):

Grain Size ◽

Amorphous Film ◽

Nitrogen Atmosphere ◽

Optical Recording ◽

Garnet Film ◽

Media Noise ◽

Garnet Films ◽

Order Of Magnitude ◽

A New Technique ◽

A Current

For future high density magneto-optical recording materials, a Bi-substituted garnet film ((BiDy)3(FeGa)5O12) is an attractive candidate since it has strong magneto-optic effect at short wavelengths less than 600 nm. The signal in read back performance at 500 nm using a garnet film can be an order of magnitude higher than a current rare earth-transition metal amorphous film. However, the granularity and surface roughness of such crystalline garnet films are the key to control for minimizing media noise.We have demonstrated a new technique to fabricate a garnet film which has much smaller grain size and smoother surfaces than those annealed in a conventional oven. This method employs a high ramp-up rate annealing (Γ = 50 ~ 100 C/s) in nitrogen atmosphere. Fig.1 shows a typical microstruture of a Bi-susbtituted garnet film deposited by r.f. sputtering and then subsequently crystallized by a rapid thermal annealing technique at Γ = 50 C/s at 650 °C for 2 min. The structure is a single phase of garnet, and a grain size is about 300A.

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Functional information from magnetic resonance imaging

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100136799 ◽

1995 ◽

Vol 53 ◽

pp. 84-85

Author(s):

Alan P. Koretsky ◽

Afonso Costa e Silva ◽

Yi-Jen Lin

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

High Resolution ◽

Cancer Biology ◽

Imaging Modality ◽

Magnetic Resonance Images ◽

Great Success ◽

Functional Information ◽

Resonance Imaging ◽

High Resolution Mri

Magnetic resonance imaging (MRI) has become established as an important imaging modality for the clinical management of disease. This is primarily due to the great tissue contrast inherent in magnetic resonance images of normal and diseased organs. Due to the wide availability of high field magnets and the ability to generate large and rapidly switched magnetic field gradients there is growing interest in applying high resolution MRI to obtain microscopic information. This symposium on MRI microscopy highlights new developments that are leading to increased resolution. The application of high resolution MRI to significant problems in developmental biology and cancer biology will illustrate the potential of these techniques.In combination with a growing interest in obtaining high resolution MRI there is also a growing interest in obtaining functional information from MRI. The great success of MRI in clinical applications is due to the inherent contrast obtained from different tissues leading to anatomical information.

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Spectroscopic imaging of human disease

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166889 ◽

1996 ◽

Vol 54 ◽

pp. 884-885

Author(s):

D.J. Meyerhoff

Keyword(s):

Magnetic Field ◽

Magnetic Resonance ◽

Field Gradient ◽

Human Disease ◽

Morphological Changes ◽

Magnetic Field Gradient ◽

Spectroscopic Imaging ◽

Resonance Spectroscopy ◽

Tissue Water

Magnetic Resonance Imaging (MRI) observes tissue water in the presence of a magnetic field gradient to study morphological changes such as tissue volume loss and signal hyperintensities in human disease. These changes are mostly non-specific and do not appear to be correlated with the range of severity of a certain disease. In contrast, Magnetic Resonance Spectroscopy (MRS), which measures many different chemicals and tissue metabolites in the millimolar concentration range in the absence of a magnetic field gradient, has been shown to reveal characteristic metabolite patterns which are often correlated with the severity of a disease. In-vivo MRS studies are performed on widely available MRI scanners without any “sample preparation” or invasive procedures and are therefore widely used in clinical research. Hydrogen (H) MRS and MR Spectroscopic Imaging (MRSI, conceptionally a combination of MRI and MRS) measure N-acetylaspartate (a putative marker of neurons), creatine-containing metabolites (involved in energy processes in the cell), choline-containing metabolites (involved in membrane metabolism and, possibly, inflammatory processes),

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