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Four olive oils with varying amounts of total phenols were exposed to four different heating conditions. Chemical parameters such as free fatty acid, peroxide values, UV absorbency, total phenols, individual phenols, α-tocopherol, squalene, oleocanthal, fatty acid profile and smoke point were measured before and after heating to evaluate the impact of heating conditions on the oils. We found olive oils have reasonably high smoke point that is suitable for typical home-cooking conditions and fresh olive oil with low FFA and high phenolics are important for the conservation of olive oil quality and health benefits. A larger degree of oxidation occurred as with increase of heating time and temperature, oils with high level of phenols produced less polar compounds than oils with lower levels of phenols, including refined oils. A significant amount of total phenols and individual phenols such as oleocanthal remained after heating at 121 °C for 10 and 20 minutes, most of squalene stay intact even after heating at 220 °C.

An aspect of David Cannadine's portrait of British aristocratic decline after 1880 is the way in which increasingly erratic parliamentary behaviour reflected a loss of political confidence and direction. The political impact of MPs from the Lowther family had over six centuries been more limited than their numbers might suggest. After 1882 their fragmentation was further encouraged by the extravagant and increasingly apolitical eccentricity of the fifth Earl. However, some of the last Lowthers were untypically prominent in the House, though — despite their shared Conservatism — in uncoordinated and often idiosyncratic ways. It is tempting to see the permanent disappearance of Lowthers from the Commons following the fall of the Coalition in 1922 as a function of aristocratic crisis, but the evidence points rather to coincidental personal factors.

A comparison of Westmorland elections at either end of the nineteenth century illustrates how a wider franchise could mean less popular involvement in the political process and a tightening of the grip of Conservatism on the county elite. But the dominance of the Lowther family was less monolithic than it seemed: the persistence of Nonconformity and owner-occupier farming, particularly in the north of the county, meant that there was always the potential for a realistic Liberal challenge if a suitably prestigious candidate would come forward, and Lowther agents had to work diligently to sustain the status quo. Parliamentary reform and coincidental Lowther upheavals in the early 1880s opened the door to a confident Liberal challenge, and only a handful of dubious votes prevented the capture of the seat in 1885. That the prospect of success then receded was partly attributable to Gladstone's fixation with Irish Home Rule, which played badly in Westmorland; but, more critically, to a damagingly publi...

Exceptionally high-quality films of Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7-x/ (YBCO) were successfully grown epitaxially on Si

Efforts aimed at producing device-quality YBa/sub 2/Cu/sub 3/O/sub 7- delta / (YBCO) films on Si, which have resulted in films with properties comparable to what can be achieved with conventional oxide substrates such as SrTiO/sub 3/, are described. It is reported how epitaxial YBCO films were grown on Si

Thin films were deposited by pulsed uv‐laser (ablation) deposition of Y1Ba2Cu3O7−x (YBCO), and composite zirconia and yttria targets onto silicon wafers. These films were analyzed to ascertain the chemical and physical structure of the film interfaces and further the development of Si substrates for superconducting YBCO films. Substrates were Si(100) with either a high‐quality, thermal oxide (SiO2) film, or a spin‐etch processed, oxide‐free, hydrogen‐terminated surface (Si:H). X‐ray photoelectron spectroscopy (XPS) of Y, Ba, Cu, and Si core levels revealed adverse reactions for thin (nominally 2 nm) YBCO films deposited directly onto either substrate surface. The surfaces of thicker YBCO films (50–100 nm) and various oxide powders were compared with XPS results from these thin films. The thicker‐film surfaces are similar to those of fractured bulk YBCO, while the thin YBCO films decomposed, as evidenced by changes in the Ba and Cu XPS. The Si XPS on these films showed the formation of metal‐silicate compounds, even at deposition substrate temperatures of 550 °C, and silica (SiO2), especially for 670 °C deposition. A direct consequence of these reactions is that growth of high‐quality epitaxial YBCO on Si will require the use of a buffer film. Yttria‐stabilized zirconia (YSZ) shows considerable promise for use as a buffer, and XPS of thin films (4 and 8 nm thick) of ZrO2 on SiO2/Si and YSZ on Si:H substrates did not show any indication of decomposition, even at deposition temperatures near 800 °C. Transmission electron microscopy of cross‐sectioned samples of YBCO/YSZ/Si showed that the lower YSZ interface is rough on the preoxidized (SiO2/Si) substrates but atomically sharp on the spin‐etched Si wafers (Si:H). These sharp YSZ interfaces showed the presence of 3–5 nm of regrown oxide (SiOx ) next to the crystalline Si substrate. This regrown oxide was observed in samples deposited under a variety of conditions.

Epitaxial YBa2Cu3O7−δ (YBCO) films were grown on Si (100) using an intermediate buffer layer of yttria‐stabilized zirconia. Both layers are grown via an entirely in situ process by pulsed laser deposition. All films consist of c‐axis oriented grains as measured by x‐ray diffraction. Strain results from the large difference in thermal expansion coefficients between Si and YBCO. Thin (

Epitaxial yttria‐stabilized zirconia films were grown on Si (100) and Si (111) by pulsed laser deposition. Rutherford backscattering spectroscopy indicates a high degree of crystalline perfection with a channeling minimum yield of 5.3%. A necessary predeposition process is removal of native silicon oxide from the Si prior to film growth. This is done outside the deposition chamber at 23 °C using a wet‐chemical hydrogen‐termination procedure. Epitaxial YBa2Cu3O7−δ films have been grown on these films.

Epitaxial YBa2Cu3O7 films were grown on Al2O3 {1012} by a laser ablation technique. X‐ray diffraction shows that films are epitaxial with the c axis perpendicular to the substrate surface and ‘‘123’’ [110] aligned with sapphire [1011], although the full width at half maximum of the rocking curve is larger than those of epitaxial films on SrTiO3. Typical Tc’s are between 85 and 88 K with transition widths between 0.5 and 3 K. The normal‐state resistivity is 270 μΩ cm at 300 K and extrapolates to zero at zero temperature while the magnetization Jc is as high as 5×106 A/cm2 at 4.2 K. High‐frequency loss measurements show that 2000‐A‐thick epitaxial films on Al2O3 {1012} have a surface impedance about 1 mΩ at 13 GHz at 4.2 K.

Pulsed laser deposition is a powerful technique for the epitaxial growth of superconducting oxide films on numerous oxide substrates. Until recently, epitaxy on silicon substrates was made impossible by the chemical reactivity and thermal expansion mismatch of silicon and superconducting oxides. By interleaving an epitaxial buffer layer of yttria-stabilized zirconia in a fully in-situ laser deposition process, we have addressed both of these problems to grow c-axis oriented, epitaxial Y 1 Ba 2 Cu 3 O 7-δ (YBCO) films on silicon. X-ray diffraction indicates an in-plane, epitaxial alignment within 2°. The films not only have high superconducting transition temperatures of 88 K but also have critical current densities of 2.2×10 6 A/cm 2 at 77 K. Transition widths are 1 K and normal state resistivities are 0.28 mOhm-cm at 300 K. Additional studies of YBCO on silicon-on-sapphire show that the limit on thickness of about 50 nm, set by thermal strain, for oxide films on bulk silicon can be overcome, and films with thicknesses far beyond this critical thickness have been grown. The surface resistance of these films at 4.2K and 11.8GHz is 72 μω cm and the critical current at 77 K is 4.6×10 6 A/cm 2 . The values of the above parameters are now high enough to enable the fabrication of micro-electronic devices with superior performance.

Efforts to grow high quality films of YBCO on Si have been complicated by factors discussed in Ref. 1, chief among them being the reaction between YBCO and Si, which is damaging even at 550 C. This is well below the customary temperatures for YBCO film growth. To avoid the reaction problem, epitaxial YBCO films were grown on Si (100) using an intermediate buffer layer of yttria-stabilized zirconia (YSZ).2 Both layers are grown via an entirely in situ process by pulsed laser deposition (PLD). Although the buffer layer prevents reaction, another problem arises; the large difference in thermal expansion coefficients between silicon and YBCO causes strain at room temperature. Thin (2x106 A/cm2 at 77 K have been achieved. In addition, the surface resistance of a YBCO film on SOS was measured against Nb at 4.2 K. At 10 GHz, a value of 45 was obtained. This compares favorably to values reported for LaAlO3. Application of this technology to produce reaction patterned microstrip lines has been tested.4 This was done by ion milling away portions of the YSZ buffer layer prior to the YBCO deposition. YBCO landing on regions of exposed Si reacts to form an insulator. This technique was used to make 3 micron lines 1.5 mm long. The resulting structure had a Jc of l.6xl06 A/cm2 at 77 K. Isolation of separate structures exceeded 20 M. Several advantages of this technique are that no solvents, etchants or photoresist come into contact with the YBCO, hence this technique has a potential for operational-asgrown devices. In summary, it is now possible to produce YBCO films with structural and DC electrical properties which rival the most optimized c-axis epitaxial YBCO films on MgO, SrTiO3 and LaAlO3. Preliminary measurements of microwave properties appear promising. We thank Bruce Lairson for help obtaining magnetization data and Richard Johnson, Steve Ready and Lars-Erik Swartz for technical assistance. This work benefits from AFOSR (F49620-89-C-0017). DBF received support from NSF (DMR- 8822353). DKF acknowledges the AT&T scholarship.

YBa2Cu3Oy thin films have been deposited in-situ on several substrate materials using pulsed excimer laser deposition. On the substrates, SrTiO3, MgO, LaA103, and yttrium-stabilized zirconia (YSZ), excellent films were obtained. These films had high superconducting transition temperatures (91K) with narrow transition widths (≈0.5K), metallic conductivity in the normal state, low room-temperature resistivity ( ~250 µΩ-cm), high critical currents (~3x107 A/cm2 at 4.2K), c-axis orientation perpendicular to the plane of the film, and epitaxial alignment with the substrate. On the more technologically relevant substrates of A12O3 and Si, less optimal results were obtained. The transition temperatures were high (86-88K) and metallic conductivity way obtained in the normal state. However, the room-temperature and microwave surface resistivities were higher and the critical currents were lower than for the above benchmark substrates. These diminished transport properties correlate with the imperfect alignment and epitaxy of the YBCO and substrate. For A12O3 substrates, a narrow substrate-temperature window was found for the best in-situ YBCO films. The poorer transport properties correlate with the lack of registry of the YBCO a-b plane with the sapphire r-plane. For Si substrates, a buffer layer is required due to high reactivity even at substrate temperatures as low as 550 C. YSZ provides a good buffer, and our best results were obtained on clean, hydrogen-terminated surfaces rather than oxidized Si. The amount of Y2O3 in ZrO2 was varied, and the best films were obtained with x near 0.1 where (ZrO2)1-x(Y2O3)x is cubic. Epitaxial alignment of the YBCO with the Si was achieved, but there was a substantial spread in orientations, accounting for the diminished transport properties.

We present data on thin films of YBa2Cu3O7 (YBCO) and YBa2(Cu1−xFex)3O7 prepared by laser ablation using a sequence of targets, including Cu-deficient YBa2Cu2.4O7, CuO, and (CuO)1−y(FeO)y. This technique achieves mixing on an atomic scale. We find that stochiometric films, made using a combination of the Cudeficient target and CuO, have a sharp transition (width < 1K) near 90K although the Cu-deficient material alone has a broad transition at a lower Tc. We have achieved substitution of Fe on the Cu sites, using a sequence of the three targets for a range of Fe concentrations. Tc decreases nearly linearly with concentration and Tc → 0 near 15% Fe. The Tc suppression for the films is slightly less than the corresponding value obtained for bulk samples.

Thin epitaxial films of cubic - fluorite structured PrO2 and YSZ (yttria- stabilized zirconia) were grown on single crystal silicon substrates using the laser ablation - deposition technique. X-ray diffraction theta two - theta, omega rocking and phi scans indicate a high degree of epitaxial orientation of the films to the Si lattice. The highest quality of epitaxy was obtained with the PrO2 [111] oriented normal to Si(111) surfaces and the cubic YSZ [100] normal to Si(100) surfaces. For both PrO2 and YSZ, high epitaxial quality required the removal of the Si native oxide prior to deposition and careful control of the deposition environment. It was further found that the YSZ films on Si(100) were an excellent surface for subsequent laser ablation of YBCO films by the usual in situ process. The resistivity of this YBCO was ≈ 250 micro-ohm-cm at 300 K, extrapolated to the resistivity -temperature origin, showed a sharp transition to zero resistance at ≈ 85 K and was nearly identical to high quality YBCO films deposited on (bulk) YSZ substrates.

Earlier attempts to produce high quality thin films of YBa 2 Cu 3 O 7− δ on Si substrates were thwarted by their reactivity and thermal expansion behavior. The collective research or several groups has demonstrated several epitaxial buffer layer systems including yttria-stabilized zirconia and MgO which allow the epitaxial growth of YBCO on Si without chemical reaction. Although direct epitaxy of YBCO on silicon may not be possible, buffer layers permit the growth of device quality YBCO films with critical current densities in excess of 10 6 A/cm 2 at 77 K. Methods have been developed to pattern these films in-situ by removing the buffer layer in selected areas to produce isolated superconducting mesas. The complications of thermally induced tensile stress have been eliminated through the use of silicon-on-sapphire instead of silicon. This work has revealed methods for controlling the in-plane epitaxy of YBCO films on zirconia via homoepitaxy and nucleation-initiating monolayers. A variety of application-oriented measurements and structures will be reported.

In the last five years excitement has been developing about the realization of a magneto-optic storage technology, based on amorphous rare-earth transition metal alloys. The goal of this paper is to identify important physics' and materials' issues that arise out of the storage, erasure and readout processes. Particular attention is paid to the origin of the magneto-optic properties in highly disordered metal alloys.

The Raman spectra of very thin evaporated films (\ensuremath{\sim}6 nm thick) of metallic titanium and oxidized titanium are obtained with a new technique called interference-enhanced Raman scattering. The results indicate that titanium films exhibit a crystalline hcp structure while the titanium oxide has an amorphous structure with local atomic bonding configurations similar to those in crystalline ${\mathrm{Ti}}_{2}$${\mathrm{O}}_{3}$.

A new model for the distribution of perpendicular magnetization in thin magnetic films supporting a circular domain is proposed. The contributions of various sources to the magnetic energy are determined and the demagnetizing effect in particular is discussed at length. It is shown that a demagnetizing energy density per unit area of the domain wall can be defined which, unlike the domain wall energy density arising from exchange and anisotropy contributions, is a function of film thickness h. For domains of large radius and small wall thickness (compared with h), the demagnetizing energy density is found to be linearly increasing with h. A typical cycle of thermomagnetic recording on a thin ferrimagnetic film with room temperature compensation point is then studied, and the effect of various parameters on the formation process and stability of reverse magnetized domains is discussed.

Several investigators have analyzed optical data on amorphous Ge films prepared by evaporation on room-temperature substrates to derive a sharp absorption edge near 0.5 eV. A re-examination of their work shows that the sharp edges, found hitherto, may be artifacts resulting from either experimental or calculational errors and that the preponderance of the current evidence favors a gradual absorption edge. Von einigen Autoren wurden die optischen Daten von amorphen Ge-Schichten, die durch Aufdampfen bei Zimmertemperatur hergestellt wurden, analysiert und daraus eine scharfe Absorptionskante bei 0,5 eV abgeleitet. Eine wiederholte Untersuchung ihrer Arbeiten zeigt, das die scharfen Kanten, die bisher gefunden wurden, Fehleffekte sein konnen, die entweder von experimentellen oder rechnerischen Fehlern herruhren und das die Mehrzahl der gegen wartigen Hinweise fur eine allmahlich ansteigende Absorptionskante spricht.

We discuss the influence of thermal response on the magneto‐optic readout performance of optically similar but thermally different quadrilayer media, using newly developed computational techniques for examining laser‐induced heat flow in moving multilayer media. We first emphasize the importance of time scale for differentiating the write and read processes. We then show that the optimum design is a function of the medium velocity and available laser power for writing and is not normally one that provides maximum signal‐to‐noise ratio in the limit that laser heating during readout can be ignored. Finally, we describe a systematic approach to the selection of the best quadrilayer design for a given set of system conditions.

Selected materials from the amorphous GexH1−x system are evaluated at 300 K as thermistor bolometers operating at photon energies between approximately 0.2 and 2.5 eV. The devices are deposited on glass and sapphire substrates by rf sputtering of polycrystalline Ge in an argon‐hydrogen atmosphere. Their current‐voltage characteristics, their response times, the frequency and spectral dependence of their responsivities, and the frequency dependence of the noise in a 3‐Hz bandwidth are all measured. Response times between 1 and 10 msec and Dλ* (0.633, 13, 1)’s of between 5×106 and 5×107 W−1 Hz1/2 cm are obtained, using a calibrated He‐Ne laser (λ=0.633 μm) as an excitation source. (At this wavelength, all nonreflected incident light is absorbed.)

Amorphous Y0.21Fe0.79 and Tb0.21Fe0.79 alloys were examined by photoemission and inverse photoemission to obtain the densities of states within ±15 eV of the Fermi level. Assuming a value of 1.8 eV for the exchange splitting of Fe, the measured densitites of Fe d-like states in both alloys could be decomposed into majority and minority spin bands, and the magnetic moment of Fe derived therefrom appears to be consistent with the splitting of the Fe 3s-core level. These results are then compared with theoretical predictions for the behavior of amorphous transition metal alloys.

Amorphography is defined as the branch of physical science which treats the structures of amorphous solids and their systematic classification. Although there is a general tendency in the literature to treat the various types of amorphous solid (semiconductors, oxides, chalcogenides, metallic alloys, etc.) as structurally distinct, there are in fact close structural relationships between members of the different classes. A systematic classification of amorphous solids is introduced in terms of the underlying topological network. The role of decoration and topological transformations is discussed and examples given of their use in generating new models of a wide range of amorphous solids.

1. 1. Eight cases of appendicitis complicating pregnancy in 20,000 deliveries are reviewed. Of these, 6 were definitely acute. 2. 2. Four occurred in the last month of pregnancy; one was an acute gangrenous appendicitis with perforation and peritonitis complicating labor. 3. 3. With the exception of this one, no unusual difficulty was encountered at operation because of the pregnant uterus, with which there was no interference. 4. 4. None of the early cases aborted or went into premature labor. 5. 5. The morbidity course following labor and delivery was not unusual, nor was peritoneal involvement increased. 6. 6. A case of acute gangrenous appendicitis with perforation and peritonitis complicating labor is presented, with the usual delay in diagnosis experienced. 7. 7. The cecum was located above the crest of the ilium and the appendix had rotated counter-clockwise under the liver, confirming observations by Baer, Reis, and Arens on the location and rotation of the appendix and cecum as they approached term.

The implicit and explicit contributions to the temperature dependence of the absorption edge in some amorphous forms of Si, Ge, GaP, and GaAs are reported. The results are used to test a model in which the valence (conduction) band states in amorphous material are a superposition of crystalline valence (conduction) band states of about the same energy. In the case of the III–V compounds, it is concluded that such a model may be invalid owing to the probable existence of “wrong” bonds. Nous presentons une etude des contributions implicites et explicites a la dependence en temperature du seuil d'absorption de certaines formes amorphes de Si, Ge, GaP et GaAs. Les resultats sont utilises pour tester un modele dans lequel les etats de la bande de valence (conduction) de la forme amorphe sont approximativement une superposition d'etats de měme energie de la bande de valence (conduction) de la forme cristalline. Nous concluons qu'il est possible qu'un tel modele ne soit pas applicable au cas des composes III–V a cause de la possibilite d'existence des liaisons “incorrectes”.

Summary Transthoracic impedance of man to direct current defibrillator discharge has been reported to vary from 27 to 110 ohms. This study was designed to determine the effect of paddle electrode size and paddle electrode-chest wall interface on transthoracic impedance. Paddle electrode diameters studied were 4.5, 8.0, and 12.8 cm. There was a progressive decrease in impedance with increasing paddle electrode size. Paddle electrode-chest wall interfaces used were none, electrode cream, saline-soaked gauze pads, and electrode paste. The transthoracic impedance was progressively decreased with these interfaces regardless of paddle electrode size. This study suggests that when using direct current defibrillators or cardioverters, large paddle electrodes should be used with electrode paste as interface to accomplish maximum reduction in transthoracic impedance.

Measurements of the absorption edge of single‐crystal and polycrystal GaN were made as a function of hydrostatic pressure up to 10 kbar at temperatures of 296 and 77 K. Its shift with stress, 4.2±0.4 meV/kbar at 296 K, is similar to the value 5.3±1.0 meV/kbar, calculated for the E0 transition by Camphausen, Connell, and Paul. The absorption near the gap could be separated into a strongly temperature‐dependent component for α≳600 cm−1 giving ∂Eg/∂T =−6.7×10−4 eV/K and a less sensitive component for α

The concavitation of the diamond anvils used in a Van Valkenburg high pressure apparatus has been studied using interference techniques. The pressure distribution was then calculated from the shape of the depression. Materials with low compressional yield stress showed a maximum of pressure at the centre, whilst materials with high compressional yield stress showed a maximum near the edges. Zinc sulphide was used to illustrate this behaviour - a powdered specimen had a phase change in the central regions, a single crystal in the outer regions.

We present an experimental investigation of our earlier theoretical predictions regarding the signal‐to‐noise ratio for magneto‐optic readout from quadrilayer structures in a differential detection scheme. Using quadrilayer structures employing amorphous Tb‐Fe alloys as the magnetic material, quartz as the dielectric material, and aluminum as the reflecting material, we show that the signal enhancement predicted for quadrilayers occurs even when the numerical aperture of the readout system is large, a crucial result for their effectiveness in magneto‐optic storage applications. We also show that the signal‐to‐noise ratios measured are in quantitative agreement with theory.

A new method of obtaining polar Kerr spectra from very thin highly absorbing films (α≳104 cm−1) is described. The technique which is termed interference enhanced Kerr spectroscopy is shown theoretically to produce a gain in the Kerr intensity of 10–103 (depending on the optical constants of the material) over that expected from a thick sample. The potential of the method is demonstrated theoretically using MnBi data and experimentally using an amorphous Tb‐Fe alloy. The use of this interference technique for studies of other mode conversion phenomena is also mentioned.

The magneto‐optical properties of rf sputtered amorphous TbxFe1−x alloys (with 0.17≤x≤0.32) were investigated using reflectivity and polar Kerr measurements from a surface overcoated in situ with SiO2. The concentration dependence of the Curie temperature, compensation temperature, and low‐temperature polar Kerr amplitude were all derived and the results compared with a mean‐field theory. The temperature behavior of the coercive force was also determined. While a considerable degree of agreement is obtained with earlier work, it appears that the low‐temperature polar Kerr amplitude can only be determined by the iron sub‐network alone, if the iron moment increases with terbium concentration. The extent to which this view is justified is examined in light of current ideas.The magneto‐optical properties of rf sputtered amorphous TbxFe1−x alloys (with 0.17≤x≤0.32) were investigated using reflectivity and polar Kerr measurements from a surface overcoated in situ with SiO2. The concentration dependence of the Curie temperature, compensation temperature, and low‐temperature polar Kerr amplitude were all derived and the results compared with a mean‐field theory. The temperature behavior of the coercive force was also determined. While a considerable degree of agreement is obtained with earlier work, it appears that the low‐temperature polar Kerr amplitude can only be determined by the iron sub‐network alone, if the iron moment increases with terbium concentration. The extent to which this view is justified is examined in light of current ideas.

It is proposed that the structure of GeSe2 glass is characterized by a chemically ordered continuous random network. Within this context it is suggested that 4-atom planar rings exist and can explain an unusual feature in the Raman spectrum. Neutron scattering data are presented which supportthis model.

A new method of obtaining Raman spectra from a very thin highly absorbing films (α≳105 cm−1) is described. The technique which is termed interference enhanced Raman scattering (IERS) is shown theoretically to produce a gain in the scattered intensity of 10–103 (depending on the optical constants of the material) over that expected from a thick sample using the conventional Raman backscattering configuration. The potential of the method is demonstrated experimentally using tellurium, and a gain of 20 is obtained.

A quadrilayer magneto-optical device in which the magnetic medium is sandwiched between two dielectric layers and supported by a reflecting substrate is shown to have desirable characteristics for both the storage and retrieval of information, The quadrilayer exhibits a readout signal to noise ratio of about 8 (3) dB over the readout from bare (coated) bulk material. At the same time, the writing sensitivity is matched to the available laser power for recording, thus permitting high levels of read power without loss in resolution. Energetics of domain formation in a ferrimagnetic material during a typical write cycle is then examined. Contributions from different sources of energy are compared and the role of coercivity in the formation and stability of domains is discussed.

A new method of obtaining polar Kerr spectra from very thin absorbing films is used to study the thickness dependence of the Curie temperature, compensation temperature and critical behavior of the Fe-subnetwork of amorphous Tb-Fe alloy films. Significant deviations from bulk behavior begin to occur a thickness below about 20 nm.

The magneto‐optic properties of rf sputtered amorphous TbxFe1−x(x≊0.21) alloys were investigated using reflectivity, ellipsometry, and polar Kerr measurements. Oxide growth in air at different temperatures was first studied, and the oxide composition and growth kinetics were correlated by ellipsometry and Auger measurements. Alloy films overcoated in situ with several thicknesses of SiO2 were then used for optical studies of the ’’unoxidized’’ interface, and the data obtained yielded the diagonal and off‐diagonal elements of the dielectric tensor of unoxidized material.

Oriented c‐axis thin films of Bi‐Ca‐Sr‐Cu‐O on [100] SrTiO3 substrates have been fabricated using the pulsed excimer laser evaporation technique. Deposition at room temperature in 1 mTorr oxygen followed by an 875 °C anneal in oxygen yields superconducting films with zero resistance at 80 K and a resistivity drop near 110 K, hinting at the presence of another superconducting phase. Transmission electron microscopy shows that the films are epitaxial with the substrate, with an abrupt and planar interface boundary. The observed crystal structure is consistent with diffraction results on bulk materials.

The magneto-optical properties of amorphous Tb 0.23 (Fe 1− y M y ) 0.77 alloys with M ≡ V, Mn, Co or Cu were measured, and the compositional dependence of the Curie temperature, compensation temperature and magnetization of the transition metal subnetwork inferred. The results suggest the location of the Fermi energy relative to the majority and minority spin bands.