Cross-Sectioning Magnetic Thin Films for Tem

1987 ◽  
Vol 115 ◽  
Author(s):  
H.-M. Ho ◽  
G. Thomas ◽  
C. N. Schooley ◽  
J.-S. Gau
Keyword(s):  
Thin Films ◽  
Porous Structure ◽  
Oblique Incidence ◽  
Magnetic Thin Films ◽  
Specimen Preparation ◽  
Video Tape ◽  
Recording Media ◽  
Preparation Technique ◽  
Poor Adhesion ◽  
Diamond Knife

ABSTRACTOblique incidence magnetic thin films are considered to be the most appropriate recording media for the next generation of video tape applications. In order to study the microstructure of such thin films, a specimen preparation technique employing ultramicrotomy has been developed. Because oblique incidence thin films have a porous structure and poor adhesion to the substrate, the problem of splitting of the thin films from the substrate is severe. This problem is reduced considerably by the following exercises: 1. using an acrylic embedding resin e.g. LR White (London Resin Co.), 2. thorough degreasing with solvents, 3. using a 55° diamond knife, and 4. trimming the block with a microtome before actual sectioning. The details of this preparation technique and some results obtained with this technique are presented.

Effect of Pt content on compositional segregation in Co-Cr-P-Pt/Cr magnetic thin films

1996 ◽  
Vol 54 ◽  
pp. 1022-1023
Author(s):  
J-H. Choi ◽  
C. M. Sung ◽  
K. H. Shin ◽  
L. F. Allard
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Magnetic Thin Films ◽  
Low Noise ◽  
Recording Media ◽  
Magnetic Recording Media ◽  
Physical Separation ◽  
Eds Analysis ◽  
Transmission Electron ◽  
Compositional Segregation

Co/Cr alloys are among the most prominent materials for ultra-high density longitudinal magnetic recording media. The recording and magnetic properties of the materials are related to their microstructure. It has been found that compositional segregation (CS) of the Co phase at the grain boundaries, and physical separation of Co/Cr phases are effective in producing low noise media due to low intergranular exchange coupling. A series of Co/Cr alloy magnetic thin films were prepared by DC sputtering and studied using high-resolution transmission electron microscopy (HRTEM) coupled with energy dispersive x-ray spectroscopy (EDS). CoxCryPzPtw/Cr alloy thin films were deposited on circumferentially textured Ni-P/Al substrate. This substrate geometry was used to get better magnetic properties without substrate bias. A Hitachi HF-2000 field emission TEM was used for imaging and to provide a 1 nm beam for high spatial resolution EDS analysis.

Nucleation and Heteroepitaxy of YBa2Cu3O7-δ thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 88-89
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Film Growth ◽  
Thin Foil ◽  
Substrate Material ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Bulk Single Crystal ◽  
Transmission Electron ◽  
Final Sample

The nucleation and heteroepitactic growth of YBa2Cu3O7−δ thin-films has been studied by transmission electron microscopy (TEM). The films were formed by pulsed-laser ablation and then observed in the TEM without further sample preparation. Direct observation of the early stages of film growth is possible due to the utilization of a new specimen-preparation technique. The films were deposited directly onto specially prepared electron-transparent substrates. The substrate material used in this study was single-crystal, (001)-oriented MgO. The thin-foil substrates were prepared from bulk single-crystal substrates in the following manner. Discs of 3mm diameter were cored, polished and dimpled to produce a final sample thickness of 10 - 20μm. The samples were ion milled to perforation using 5 kV Ar+ ions, then chemically cleaned. The cleaned foils were annealed in air at 1350°C for 10min. The annealing temperature is such that sufficient atomic mobility enables the formation of a series of steps on the surface.

Imaging Thin Films of Nanoporous Low-k Dielectrics: Comparison between Ultramicrotomy and Focused Ion Beam Preparations for Transmission Electron Microscopy

2005 ◽  
Vol 12 (2) ◽  
pp. 156-159 ◽  
Author(s):  
Leslie E. Thompson ◽  
Philip M. Rice ◽  
Eugene Delenia ◽  
Victor Y. Lee ◽  
Phillip J. Brock ◽  
...  
Keyword(s):  
Thin Films ◽  
Cross Section ◽  
Focused Ion Beam ◽  
Preparation Method ◽  
Ion Beam ◽  
Specimen Preparation ◽  
Ion Milling ◽  
Transmission Electron ◽  
Low K ◽  
Diamond Knife

Ultramicrotomy, the technique of cutting nanometers-thin slices of material using a diamond knife, was applied to prepare transmission electron microscope (TEM) specimens of nanoporous poly(methylsilsesquioxane) (PMSSQ) thin films. This technique was compared to focused ion beam (FIB) cross-section preparation to address possible artifacts resulting from deformation of nanoporous microstructure during the sample preparation. It was found that ultramicrotomy is a successful TEM specimen preparation method for nanoporous PMSSQ thin films when combined with low-energy ion milling as a final step. A thick, sacrificial carbon coating was identified as a method of reducing defects from the FIB process which included film shrinkage and pore deformation.

Contrast from epitaxially sandwiched macromolecules

1978 ◽  
Vol 36 (2) ◽  
pp. 226-227
Author(s):  
M. Talianker ◽  
D.G. Brandon
Keyword(s):  
Gold Film ◽  
Lattice Defect ◽  
Gold Foil ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Resolution Limit ◽  
Transmission Electron ◽  
Crystal Lattice Defect ◽  
Void Effect ◽  
Lattice Resolution

A new specimen preparation technique for visualizing macromolecules by conventional transmission electron microscopy has been developed. In this technique the biopolymer-molecule is embedded in a thin monocrystalline gold foil. Such embedding can be performed in the following way: the biopolymer is deposited on an epitaxially-grown thin single-crystal gold film. The molecule is then occluded by further epitaxial growth. In such an epitaxial sandwich an occluded molecule is expected to behave as a crystal-lattice defect and give rise to contrast in the electron microscope.The resolution of the method should be limited only by the precision with which the epitaxially grown gold reflects the details of the molecular structure and, in favorable cases, can approach the lattice resolution limit.In order to estimate the strength of the contrast due to the void-effect arising from occlusion of the DNA-molecule in a gold crystal some calculations were performed.

The ionic strength dependence of chromatin folding

1978 ◽  
Vol 36 (2) ◽  
pp. 220-221
Author(s):  
F. Thoma ◽  
TH. Koller
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Ionic Strength ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Carbon Supports ◽  
Ionic Strength Dependence ◽  
Chromatin Folding ◽  
Strength Dependence ◽  
Preparation Techniques

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.

SEM evaluation of the TEM cold-stage double-film specimen

1984 ◽  
Vol 42 ◽  
pp. 272-273
Author(s):  
Jayesh Bellare
Keyword(s):  
Spatial Distribution ◽  
Sample Preparation ◽  
Sample Thickness ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Liquid Sample ◽  
Thin Specimen ◽  
Sample Preparation Technique ◽  
Cold Stage ◽  
Film Specimen

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.

Transmission Electron Microscopy studies of texture of Cr underlayer of magnetic recording hard disk

1991 ◽  
Vol 49 ◽  
pp. 580-581
Author(s):  
L. Tang ◽  
G. Thomas ◽  
M. R. Khan ◽  
S. L. Duan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Magnetic Recording ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Substrate Bias ◽  
Epitaxial Relationship ◽  
Transmission Electron

Cr thin films are often used as underlayers for Co alloy magnetic thin films, such as Co1, CoNi2, and CoNiCr3, for high density longitudinal magnetic recording. It is belived that the role of the Cr underlayer is to control the growth and texture of the Co alloy magnetic thin films, and, then, to increase the in plane coercivity of the films. Although many epitaxial relationship between the Cr underlayer and the magnetic films, such as ﹛1010﹜Co/ {110﹜Cr4, ﹛2110﹜Co/ ﹛001﹜Cr5, ﹛0002﹜Co/﹛110﹜Cr6, have been suggested and appear to be related to the Cr thickness, the texture of the Cr underlayer itself is still not understood very well. In this study, the texture of a 2000 Å thick Cr underlayer on Nip/Al substrate for thin films of (Co75Ni25)1-xTix dc-sputtered with - 200 V substrate bias is investigated by electron microscopy.

Ultramicrotomy as a Technique for Materials Specimen Preparation

1990 ◽  
Vol 48 (2) ◽  
pp. 428-429
Author(s):  
S.R. Glanvill
Keyword(s):  
Materials Science ◽  
Structural Information ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Cross Sectional ◽  
Surfaces And Interfaces ◽  
Beam Analysis ◽  
Flat Embedding ◽  
20 Nm ◽  
Sectional Analysis

This paper summarizes the application of ultramicrotomy as a specimen preparation technique for some of the Materials Science applications encountered over the past two years. Specimens 20 nm thick by hundreds of μm lateral dimension are readily prepared for electron beam analysis. Materials examined include metals, plastics, ceramics, superconductors, glassy carbons and semiconductors. We have obtain chemical and structural information from these materials using HRTEM, CBED, EDX and EELS analysis. This technique has enabled cross-sectional analysis of surfaces and interfaces of engineering materials and solid state electronic devices, as well as interdiffusion studies across adjacent layers.Samples are embedded in flat embedding moulds with Epon 812 epoxy resin / Methyl Nadic Anhydride mixture, using DY064 accelerator to promote the reaction. The embedded material is vacuum processed to remove trapped air bubbles, thereby improving the strength and sectioning qualities of the cured block. The resin mixture is cured at 60 °C for a period of 80 hr and left to equilibrate at room temperature.

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