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31 Aug 1987

Volume 51, Issue 9, pp. 631-702


Supermode discrimination in diffraction‐coupled laser arrays with separate contacts

J. Z. Wilcox, M. Jansen, J. Yang, G. Peterson, A. Silver, W. Simmons, S. S. Ou, and M. Sergant

Appl. Phys. Lett. 51, 631 (1987); http://dx.doi.org/10.1063/1.98369 (3 pages) | Cited 3 times

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We show that in‐phase lasing is favored in diffraction‐coupled arrays with separate electrical contacts for the common unguided diffraction zone and for the waveguide section, if the common unguided section is biased above a critical level. Below that level, out‐of‐phase lasing will be favored. By varying the current about the critical level, the far‐field intensity switches from a wide far‐field pattern characterized by the admixture of several supermodes, to a near‐diffraction‐limited single peak.
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42.60.By Design of specific laser systems
42.60.Fc Modulation, tuning, and mode locking
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Two‐electrode distributed feedback injection laser for single‐mode stabilization and electro‐optical switching

K.‐Y. Liou, C. A. Burrus, U. Koren, and T. L. Koch

Appl. Phys. Lett. 51, 634 (1987); http://dx.doi.org/10.1063/1.98370 (3 pages) | Cited 2 times

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By utilizing two electrodes on a conventional uniform‐grating distributed feedback (DFB) injection laser, the usual two‐mode DFB laser degeneracy has been removed to permit (1) single‐frequency operation with 33‐dB side‐mode suppression and (2) current‐controlled switching between the two modes, separated by a 10–25 Å stop band, in less than 1 ns.
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42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Px Semiconductor lasers; laser diodes
42.55.Rz Doped-insulator lasers and other solid state lasers

Room‐temperature continuous operation of p‐n AlxGa1−xAs‐GaAs quantum well heterostructure lasers grown on Si

D. G. Deppe, N. Holonyak, D. W. Nam, K. C. Hsieh, G. S. Jackson, R. J. Matyi, H. Shichijo, J. E. Epler, and H. F. Chung

Appl. Phys. Lett. 51, 637 (1987); http://dx.doi.org/10.1063/1.98371 (3 pages) | Cited 46 times

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We describe the construction and room‐temperature (300 K) continuous (cw) operation of p‐n diode AlxGa1−xAs‐GaAs quantum well heterostructure (QWH) lasers grown on Si substrates. The QWH crystal is grown in two stages, the first part by molecular beam epitaxy (MBE) and the single‐well quantum well active region by metalorganic chemical vapor deposition (MOCVD). Simple gain‐guided stripe configuration lasers fabricated on the MBE MOCVD QWH wafer operate cw at 300 K and have pulsed thresholds as low as 1.8×103 A/cm2.
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42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Px Semiconductor lasers; laser diodes
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
42.60.By Design of specific laser systems

Submicrosecond electro‐optic switching in the liquid‐crystal smectic A phase: The soft‐mode ferroelectric effect

G. Andersson, I. Dahl, P. Keller, W. Kuczyński, S. T. Lagerwall, K. Skarp, and B. Stebler

Appl. Phys. Lett. 51, 640 (1987); http://dx.doi.org/10.1063/1.98341 (3 pages) | Cited 106 times

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A new liquid‐crystal electro‐optic modulating device similar to the surface‐stabilized ferroelectric liquid‐crystal device is described. It uses the same kind of ferroelectric chiral smectics and the same geometry as that device (thin sample in the ‘‘bookshelf ’’ layer arrangement) but instead of using a tilted smectic phase like the C∗ phase, it utilizes the above‐lying, nonferroelectric A phase, taking advantage of the electroclinic effect. The achievable optical intensity modulation that can be detected through the full range of the A phase is considerably lower than for the surface‐stabilized device, but the response is much faster. Furthermore, the response is strictly linear with respect to the applied electric field. The device concept is thus appropriate for modulator rather than for display applications. We describe the underlying physics and present measurements of induced tilt angle, of light modulation depth, and of rise time.
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42.79.Hp Optical processors, correlators, and modulators
78.20.Jq Electro-optical effects
61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order
77.80.-e Ferroelectricity and antiferroelectricity

Measurement of the coherence of a single‐mode phase‐locked diode laser array

N. W. Carlson, V. J. Masin, M. Lurie, B. Goldstein, and G. A. Evans

Appl. Phys. Lett. 51, 643 (1987); http://dx.doi.org/10.1063/1.98342 (3 pages) | Cited 6 times

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The coherence of the light output of a single‐mode phase‐locked array has been experimentally measured. An analysis of the effects of partial coherence on the far‐field pattern of a single‐mode phased array is also presented.
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42.60.Fc Modulation, tuning, and mode locking
42.55.Px Semiconductor lasers; laser diodes

In situ observation on electron beam induced chemical vapor deposition by Auger electron spectroscopy

Shinji Matsui and Katsumi Mori

Appl. Phys. Lett. 51, 646 (1987); http://dx.doi.org/10.1063/1.98343 (3 pages) | Cited 5 times

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W deposition, using WF6 gas source by electron beam induced surface reaction, has been studied by Auger electron spectroscopy. W Auger electron signals have been observed for WF6 adlayer by Auger electron spectroscopy. Moreover, initial growth for W deposition has been observed in situ by Auger electron spectroscopy. As a result, it became clear that a growth rate for W deposition is proportional to WF6 gas pressure and can be ∼1 Å/min at 2×10−7 Torr.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
79.20.Kz Other electron-impact emission phenomena
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Evidence of interfacial melting during pulsed laser irradiation of Ni2Si on Si

M. G. Grimaldi, F. Priolo, P. Baeri, E. Rimini, A. G. Cullis, and N. G. Chew

Appl. Phys. Lett. 51, 649 (1987); http://dx.doi.org/10.1063/1.98344 (3 pages) | Cited 4 times

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Interfacial melting of thin (∼65 nm) Ni2Si films thermally grown on 〈111〉 Si has been observed after pulsed laser irradiation. Low‐energy implanted Bi was used as a marker to detect surface melting. Rutherford backscattering spectrometry has shown that the energy density threshold for interfacial mixing was lower than the one at which changes in the Bi profile occurred. Cross‐section transmission electron microscopy performed on those samples has shown the existence of a reacted layer, ∼20 nm, at the silicide/silicon interface while no change in the structure of the outermost 50 nm was observed. The reacted layer formed sharp interfaces with both the underlying silicon and the silicide. Interfacial melting has been related to the presence in the phase diagram of an eutectic between the compound and the pure silicon.
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68.35.Fx Diffusion; interface formation
64.70.D- Solid-liquid transitions
68.55.-a Thin film structure and morphology

Brillouin scattering from Love waves in Cu/Nb metallic superlattices

J. A. Bell, R. J. Zanoni, C. T. Seaton, G. I. Stegeman, W. R. Bennett, and C. M. Falco

Appl. Phys. Lett. 51, 652 (1987); http://dx.doi.org/10.1063/1.98323 (3 pages) | Cited 20 times

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Love waves have been observed for the first time by Brillouin scattering. The c12 constant of the metallic superlattice Cu/Nb has been measured.
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68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
78.35.+c Brillouin and Rayleigh scattering; other light scattering
43.35.Pt Surface waves in solids and liquids
62.20.D- Elasticity

Correlation of trap creation with electron heating in silicon dioxide

D. J. DiMaria

Appl. Phys. Lett. 51, 655 (1987); http://dx.doi.org/10.1063/1.98324 (3 pages) | Cited 41 times

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Electron trap creation in thin films of silicon dioxide is shown to follow the electron heating characteristic of this material. No trap creation is observed in the near‐thermal transport regime at electric field magnitudes less than 1.5 MV/cm. At these low fields, electrons travel in a streaming fashion close to the bottom of the oxide conduction band at energies less than that of the dominant optical phonon mode at 0.153 eV. At higher electric fields, the rate of bulk trap creation is proportional to the average energy of the hot electrons which move in a dispersive manner and can reach energies as large as 4 eV. Also, interface charge and interface state buildup are observed to be proportional to electron capture into bulk traps in the as‐fabricated oxides or into those induced by the passage of hot electrons.
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73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
73.61.Ng Insulators

Abnormal outdiffusion behavior of the deep level EL2 at the surface layer of undoped semi‐insulating GaAs

Masayoshi Matsui and Tadao Kazuno

Appl. Phys. Lett. 51, 658 (1987); http://dx.doi.org/10.1063/1.98325 (3 pages) | Cited 3 times

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p‐type thermal conversion of high‐purity undoped semi‐insulating GaAs after annealing at 850 °C in H2 gas has been investigated. It has been found that the p‐type carrier concentration at the surface layer quantitatively matches the residual carbon concentration in the bulk. The concentrations of the other acceptor impurities (Mn, Zn, Cu, Cr) in the sample are confirmed to be negligibly small. The depth profile of the carrier concentration indicates that the concentration of the EL2 level increases as the sixth power of the depth near the surface region and that it exhibits a linear dependence on depth in the deeper region. A possible mechanism for this abnormal behavior of the EL2 level is discussed.
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73.25.+i Surface conductivity and carrier phenomena
71.55.Eq III-V semiconductors
61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients
66.30.Lw Diffusion of other defects

Solid‐state interdiffusion reactions in Ni/Ti and Ni/Zr multilayered thin films

W. J. Meng, B. Fultz, E. Ma, and W. L. Johnson

Appl. Phys. Lett. 51, 661 (1987); http://dx.doi.org/10.1063/1.98326 (3 pages) | Cited 31 times

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We have performed a comparative transmission electron microscopy study of solid‐state interdiffusion reactions in multilayered Ni/Zr and Ni/Ti thin films. The Ni‐Zr reaction product was amorphous while the Ni‐Ti reaction product was a simple intermetallic compound. Because thermodynamic and chemical properties of these two alloy systems are similar, we suggest kinetic origins for this difference in reaction product.
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66.30.Ny Chemical interdiffusion; diffusion barriers
68.35.Fx Diffusion; interface formation
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

Thermally stable, low‐resistance NiInW ohmic contacts to n‐type GaAs

Masanori Murakami and W. H. Price

Appl. Phys. Lett. 51, 664 (1987); http://dx.doi.org/10.1063/1.98327 (3 pages) | Cited 29 times

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A new thermally stable, low‐resistance NiInW contact metal to n‐type GaAs has been developed by depositing a thin In layer with Ni and W layers and annealing at elevated temperatures for a short time. Low resistances of ∼0.3 Ω mm were obtained at annealing temperatures in the range of 800 to 1000 °C. The contact resistances were stable during subsequent annealings at 400 °C for 100 h and 500 °C for 10 h. The thermal stability of the contact resistance and the surface morphology of this contact are superior to those of the conventionally used AuNiGe contacts and this new contact is suitable for various device applications. Further reduction of the contact resistance can be achieved simply by reducing the sheet resistance of the contact metals.
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73.40.Cg Contact resistance, contact potential
73.40.Ns Metal-nonmetal contacts
68.55.-a Thin film structure and morphology
68.60.Dv Thermal stability; thermal effects

Resonant Raman scattering and exciton‐optical phonon coupling in CdTe/(Cd,Mn)Te quantum wells

S.‐K. Chang, H. Nakata, A. V. Nurmikko, R. L. Gunshor, and L. A. Kolodziejski

Appl. Phys. Lett. 51, 667 (1987); http://dx.doi.org/10.1063/1.98328 (3 pages) | Cited 4 times

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Resonant Raman scattering at the E0 gap from longitudinal optical phonons in CdTe/(Cd,Mn)Te multiple quantum wells has been studied near the strain split n=1 exciton ground state. A large resonance enhancement is observed with distinct incoming and outgoing channels, in agreement with luminescence excitation spectra. Phonons are observed from CdTe wells and (Cd,Mn)Te barriers, indicative of small valence‐band offsets for this superlattice system. At extreme resonance, striking linewidth broadening and damping effects for the alloy phonon modes are witnessed.
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78.30.Fs III-V and II-VI semiconductors
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Device quality growth and characterization of (110) GaAs grown by molecular beam epitaxy

L. T. P. Allen, E. R. Weber, J. Washburn, and Y. C. Pao

Appl. Phys. Lett. 51, 670 (1987); http://dx.doi.org/10.1063/1.98329 (3 pages) | Cited 20 times

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Device quality (110)GaAs has been reproducibly grown by molecular beam epitaxy (MBE) for the first time. Angling of the substrate to expose stable, Ga‐rich ledges on the (110) surface has been shown to be the necessary condition for two‐dimensional growth. The layers exhibit a room‐temperature electron mobility of ∼5700 cm2/V s for NSi∼4×1015 and a strong exciton photoluminescence emission at 4 K. This breakthrough in MBE growth of III‐V compounds allows for fabrication of (110) GaAs devices which will take advantage of the unique properties of this orientation.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
85.30.De Semiconductor-device characterization, design, and modeling
78.55.Cr III-V semiconductors
73.50.Dn Low-field transport and mobility; piezoresistance

Cooling of hot carriers in Ga0.47In0.53As

H. Lobentanzer, H.‐J. Polland, W. W. Rühle, W. Stolz, and K. Ploog

Appl. Phys. Lett. 51, 673 (1987); http://dx.doi.org/10.1063/1.98330 (3 pages) | Cited 14 times

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Carrier cooling is measured in an Al0.48In0.52As/Ga0.47In0.53As/InP heterostructure by time‐resolved photoluminescence experiments for excitation densities between 5×1016 and 2.2×1018 cm−3. For low excitation density, the energy‐loss rate by emission of optical phonons is close to theoretical bulk value, whereas a reduction of the energy‐loss rate by a factor of 100 is found for the highest excitation density.
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72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
78.55.Cr III-V semiconductors
63.20.K- Phonon interactions

Grain boundary segregation of oxygen and carbon in polycrystalline silicon

S. Pizzini, P. Cagnoni, A. Sandrinelli, M. Anderle, and R. Canteri

Appl. Phys. Lett. 51, 676 (1987); http://dx.doi.org/10.1063/1.98331 (3 pages) | Cited 26 times

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The electrical activity of grain boundaries (GB’s) in polycrystalline silicon is strongly affected by heat treatments, which are known to induce the segregation of oxygen. The large, quantitative variations of the electrical activity of GB’s observed experimentally, which are a function not only of the heat treatments but also of the carbon and oxygen content of the specific sample examined, could not be explained however, without assuming that carbon and oxygen play a synergistic role. We demonstrate in this work, by using secondary ion mass spectrometry, that oxygen and carbon segregate simultaneously, albeit spatially resolved, at grain boundaries. This result appears to be of major importance when interpreting electron or light beam induced current profiles at grain boundaries in polycrystalline silicon.
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81.40.Rs Electrical and magnetic properties related to treatment conditions
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
61.72.Mm Grain and twin boundaries
66.30.J- Diffusion of impurities

Infrared studies of the dynamics of transformations between normal and metastable state of the EL2 center in GaAs

F. Fuchs and B. Dischler

Appl. Phys. Lett. 51, 679 (1987); http://dx.doi.org/10.1063/1.98332 (3 pages) | Cited 17 times

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The bleaching of the EL2 absorption and its thermal regeneration are typical time‐dependent processes. Compared to the conventional time transient analysis, faster and more accurate data acquisition is described. This technique is based on the combined use of optical absorption and its time derivative, measured while either the energy of the bleaching light or the sample temperature is varied. The peak of the spectral response for bleaching shifts to lower energies in the temperature range 10 to 130 K. The activation energy for thermal regeneration can decrease by a factor of 6 between semi‐insulating and n‐type samples. We report the first optical identification of persistent electrons, which are photogenerated during EL2 bleaching at 10 K. The thermal disappearance of persistent electrons and holes has also been studied.
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78.30.-j Infrared and Raman spectra
78.40.Fy Semiconductors
71.55.Eq III-V semiconductors

Heterointerface stability in GaAs‐on‐Si grown by metalorganic chemical vapor deposition

S. J. Pearton, D. L. Malm, L. A. Heimbrook, J. Kovalchick, C. R. Abernathy, R. Caruso, S. M. Vernon, and V. E. Haven

Appl. Phys. Lett. 51, 682 (1987); http://dx.doi.org/10.1063/1.98333 (3 pages) | Cited 16 times

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The stability of the electrical and structural properties of GaAs directly deposited on Si by metalorganic chemical vapor deposition is examined. Extended annealing at 900 °C leads to substantial diffusion of Si across the heterointerface while under the same conditions there is no significant motion of Si incorporated as a dopant into the GaAs surface region. The degree of enhancement of Si diffusion ranges from a factor of ∼250 for 0.5‐μm‐thick GaAs films to ∼5 for 4‐μm‐thick films. The annealing time and GaAs layer thickness dependence of Si diffusivity near the interface is consistent with a defect‐modulated mechanism. A large fraction of this mobile Si is electrically inactive.
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68.60.Dv Thermal stability; thermal effects
68.35.Fx Diffusion; interface formation
73.61.Ey III-V semiconductors
81.40.Rs Electrical and magnetic properties related to treatment conditions

Cellular and dendritic morphologies on stationary and moving liquid‐solid interfaces in zone‐melting recrystallization

J. S. Im, H. Tomita, and C. V. Thompson

Appl. Phys. Lett. 51, 685 (1987); http://dx.doi.org/10.1063/1.98334 (3 pages) | Cited 14 times

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It is well known that when Si films are radiatively heated there exists a range of incident intensities for which liquid and solid regions coexist at near uniform temperature. Based on in situ microscopic observation of solidification interface morphologies, we argue that this phenomenon is responsible, at least in part, for the morphology of the liquid‐solid interface in zone‐melting recrystallization. We demonstrate this effect through stationary interface experiments. It is observed that even a stationary interface exposed to a gradient in radiation intensity develops interface morphologies similar to those of moving interfaces.
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68.08.-p Liquid-solid interfaces
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
81.10.Fq Growth from melts; zone melting and refining
81.30.Fb Solidification
64.70.D- Solid-liquid transitions

Proximity effect depression of the critical temperature in two‐phase Nb‐Ti superconductors

C. Meingast, M. Daeumling, P. J. Lee, and D. C. Larbalestier

Appl. Phys. Lett. 51, 688 (1987); http://dx.doi.org/10.1063/1.98335 (2 pages) | Cited 6 times

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The superconducting critical temperature of high critical current density Nb‐Ti composites has been measured at various stages in the critical current optimization process. This process involves heat treatment steps which cause precipitation of normal α‐Ti and make the matrix more Nb rich. Tc rises from 9.1 to 9.5 K during this stage. The final optimization stage involves extensive wire drawing during which the α‐Ti precipitates are reduced to less than a coherence length in thickness. This does not result in a reduction in Jc but Tc is found to fall from 9.44 to 8.7 K during this step. The depression of Tc is found to be in fair agreement with the predicted proximity effect suppression of Tc. Wires of optimum transport critical current density are seen to have Tc of around 9 K.
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74.25.Sv Critical currents
74.62.Bf Effects of material synthesis, crystal structure, and chemical composition
81.40.Rs Electrical and magnetic properties related to treatment conditions
74.50.+r Tunneling phenomena; Josephson effects

Preparation of single crystals of superconducting YBa2Cu3O7−x from CuO melts

M. A. Damento, K. A. Gschneidner, and R. W. McCallum

Appl. Phys. Lett. 51, 690 (1987); http://dx.doi.org/10.1063/1.98336 (2 pages) | Cited 15 times

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Millimeter size single crystals of superconducting YBa2Cu3O7−x (Tc ∼90 K) were grown by melting a mixture of stoichiometric YBa2Cu3O7−x plus excess CuO at 1150 °C followed by holding at 900 °C for four days. Crystals were in the form of plates with c axis normal to the plate face. Growth of the crystals is believed to be aided by a liquid phase which is present at the holding temperature.
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81.10.Fq Growth from melts; zone melting and refining
74.70.-b Superconducting materials other than cuprates

Relationship between superconductivity and lattice distortion in Y‐Ba‐Cu‐O compounds

Xiaobiao Zeng, Xiaoping Jiang, Hongbo Qi, Dexing Pang, Naiping Zhu, and Ze Zhang

Appl. Phys. Lett. 51, 692 (1987); http://dx.doi.org/10.1063/1.98337 (2 pages) | Cited 11 times

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The letter presents an explanation for the reversal of peak intensities in x‐ray diffraction patterns of Y‐Ba‐Cu‐O compounds with the same nominal compositions but distinctive properties of superconductivity due to different cooling conditions. Structural differences between the phases caused by different lattice distortions as well as the effect of these distortions on superconductivity are also discussed.
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74.10.+v Occurrence, potential candidates
74.70.-b Superconducting materials other than cuprates
61.66.Fn Inorganic compounds
81.40.Rs Electrical and magnetic properties related to treatment conditions

Superconducting Y‐Ba‐Cu‐O oxide films by sputtering

M. Hong, S. H. Liou, J. Kwo, and B. A. Davidson

Appl. Phys. Lett. 51, 694 (1987); http://dx.doi.org/10.1063/1.98338 (3 pages) | Cited 98 times

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We have prepared superconducting thin films of Y‐Ba‐Cu‐O with Tc onsets above 95 K by both diode and magnetron sputtering. Films with full superconductivity (R=0) at 85 K have been produced by dc magnetron sputtering. The compositions of the films are fairly uniform across an area 50 mm in diameter and through the film thickness. Structural properties of the films were studied by x‐ray diffraction. Critical current densities in the range of 3000 to 104 A/cm2 have been measured at 4.2 K.
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81.15.Cd Deposition by sputtering
74.78.-w Superconducting films and low-dimensional structures
68.55.-a Thin film structure and morphology
68.55.Nq Composition and phase identification

Beneficial effect of Co substitution on the magnetic properties of rapidly quenched Nd‐Fe‐B

J. Wecker and L. Schultz

Appl. Phys. Lett. 51, 697 (1987); http://dx.doi.org/10.1063/1.98339 (3 pages) | Cited 20 times

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Isotropic Nd15(Fe1−xCox)77B8 ribbons are produced by conventional melt spinning. For moderate Co additions the coercivity HcI increases while the remanence Jr remains almost constant. Co contents above x=0.3 lead to decreasing HcI and Jr values. The beneficial effect of Co on coercivity is ascribed to the occurrence of a Nd‐Fe‐Co minority phase which serves as pinning center for domain walls. The temperature characteristic of the coercivity and the remanence is substantially improved due to the increased Curie temperature Tc and the pinning‐type behavior of the material.
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75.50.Vv High coercivity materials
75.60.Ch Domain walls and domain structure
75.50.Bb Fe and its alloys
75.30.-m Intrinsic properties of magnetically ordered materials

Permanent magnet helical wiggler for free‐electron laser and cyclotron maser applications

G. Bekefi and J. Ashkenazy

Appl. Phys. Lett. 51, 700 (1987); http://dx.doi.org/10.1063/1.98340 (3 pages) | Cited 1 time

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A permanent magnet, ‘‘bifilar’’ helical wiggler for use in free‐electron lasers and cyclotron masers has been designed, assembled, and measured. It is composed of a cylindrical array of staggered samarium‐cobalt bar magnets, transversely magnetized and held in place in an axially grooved hollow metal cylinder. High‐quality helically polarized fields of several kilogauss can be readily achieved.
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41.60.Cr Free-electron lasers
41.20.Gz Magnetostatics; magnetic shielding, magnetic induction, boundary-value problems
84.40.Ik Masers; gyrotrons (cyclotron-resonance masers)
52.59.Px Hard X-ray sources
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