Showing papers by "Johannes Kepler University of Linz published in 1977"
TL;DR: In this paper, the mass-anisotropy of the secondary valence band extrema of PbTe has been determined experimentally and the orientation of the main axis of the constant energy ellipsoids and the mass anisotropic ratio was determined.
Abstract: The orientation of the main axis of the constant-energy ellipsoids and the mass-anisotropy ratio $\frac{{m}_{l}}{{m}_{t}}$ of the secondary valence-band extrema of PbTe has been determined experimentally. These extrema are generally believed to be located at the $\ensuremath{\Sigma}$ point of the Brillouin zone. Investigation of the anisotropy behavior of the coefficient of the conductivity of warm holes and magnetoresistance measurements showed that the main axes of these ellipsoids are parallel to 100g and do not coincide with the symmetry direction of the $\ensuremath{\Sigma}$ point. The value of the mass-anisotropy ratio for the secondary valence band in PbTe is approximately 10. It has been derived from magnetoresistance experiments.
99 citations
TL;DR: In this paper, the influence of defects on structural transition temperature on structural transitions is studied. At the local transition temperature T l c, a localized phonon condenses and the resulting cluster couples linearly to the band phonons and gives a central peak.
48 citations
TL;DR: In this paper, the precision time-of-flight measuring system and the Q3D spectrograph of the Munich Tandem Laboratory were used to measure the 3 He, t reaction on 26 Mg, 34 S, 42 Ca, 46 Ti, 50 Cr and 54 Fe with an accuracy of 0.4-0.6 keV.
46 citations
TL;DR: In this article, the reflectivity spectra of lead telluride epitaxial layers on BaF2 and NaCl substrates were investigated in the wave-number range of 5-100 cm−1.
Abstract: Reflectivity spectra of lead telluride epitaxial layers on BaF2 and NaCl substrates have been investigated in the wave-number range of 5–100 cm−1. Due to multiple reflections and interference effects in the sandwich samples, weak structures in the reflectivity spectra are accentuated. This leads to a more precise determination of the lattice parameters, especially the TO-phonon mode frequency as compared to measurements using bulk samples. By measuring the back-surface (NaCl or BaF2) reflectivity, an additional advantage caused by a kind of index matching is achieved. The temperature dependence (T = 4.2–300 K) and the carrier concentration dependence of the PbTe TO-phonon mode frequency was determined.
28 citations
TL;DR: In this paper, a systematic investigation on the dependence of the grain size of continuous (after coalescence) PbTe films on the growth conditions is carried out, where the films were deposited epitaxially on BaF 2 substrates.
22 citations
TL;DR: In this article, the critical behavior of uniaxial ferromagnets is studied by an anisotropic renormalization transformation, which is based on a timedependent Ginzburg Landau model for a nonconserved and for a conserved order parameter.
Abstract: The critical behaviour of uniaxial ferromagnets is studied by an anisotropic renormalization transformation. For dimensionalityd smaller than the critical dimensionalityd
c
(d
u
), which depends on the dimensionality of the uniaxial directiond
u
, the critical exponents are computed by thee-expansion. The critical dynamics is based on a timedependent Ginzburg Landau model, for a non-conserved and for a conserved order parameter. For the experimentally relevant cased=3 andd
u
=1 the logarithmic corrections in the frequency dependent susceptibility are computed.
18 citations
TL;DR: In this article, the depth of a foreign layer in a known bulk material is determined by a relative X-ray yield measurement at two proton energies, and the reliability is demonstrated by analysing targets of known compositions.
16 citations
TL;DR: In this article, Proton-induced K-shell X-ray yield ratios for AgCuAg sandwich targets were calculated for a particular known target, and measured yield ratios were compared with calculations to determine the Ag layer thickness.
12 citations
TL;DR: In this paper, a variable density inversion layer on p -PbTe was observed to have a mobility on the order of 250,000 cm 2 V -1 sec -1, and Shubnikov-de Haas oscillations in the channel conductivity were measured in magnetic fields up to 6 T. From the observed periodicity, it was concluded that the oscillations represent only a fraction of the total number of electrons in the inversion channel.
12 citations
9 citations
TL;DR: In this paper, the Hall-coefficient was measured on n-PbTe at 80K in different crystallographic directions as a function of electric field up to 1.1kV/cm and magnetic fields up to 0.6T.
01 Mar 1977
TL;DR: Local iteration methods for the solution of nonlinear operator equations T(x)=0 can be “globalized” by the method of embedding, which means that the initial valuex0 need not be in the neighbourhood of a solution $$\bar x$$ .
Abstract: Lokale Iterationsverfahren zur Losung von nichtlinearen OperatorgleichungenT(x)=0 konnen mit der Methodik der Einbettung „globalisiert” werden, d. h. man benotigt dann keine Startwertex0 aus der unmittelbaren Umgebung einer Losung\(\bar x\).
TL;DR: The language Mums is introduced, where all the statements of that language are macro calls of the 360 assembly language so that they can be processed by the 360 assembler without the need of a compiler.
Abstract: The presentation of STRCMACS by Barth in Sigplan Notices 11(1976),8 causes me to introduce a similar system: the language Mums (maschinenunabhangige _Makrosprache) . All the statements of that language are macro calls of the 360 assembly language . Thus they can be processed by the 360 assembler without the need of a compiler . Contrary to the approaches of other macro languages (STRCMACS BIOMAC /2/, PIT /3/, Kessler's system /4/) Mums' main objectives are :
01 Jan 1977
TL;DR: In this article, the authors verwendet man zur Globalisierung von Iterationsverfahren Stetigkeits methoden, e.g., den minimal residualum des residualum.
Abstract: Bei der Losung nichtlinearer Gleichungen verwendet man zur Globalisierung von Iterationsverfahren Stetigkeitsmethoden. Fur das Verfahren des minimalen Residuums werden dazu hinreichende Bedingungen angegeben; dieselben Bedingungen erlauben (bei gleichmasiger Stufenbreite Δs und k=k (Δs) Iterationen/Stufe) eine Minimierung der Gesamtzahl der Iterationen. Im Fall einer Singularitat von B:=T→x (x,s) werden verschiedene Losungsalternativen (Zerlegung von B unter Verwendung verschiedener Null-Raume, Vermeidung von Bifurkation durch Parameterwechsel) diskutiert.
TL;DR: In this article, a fast light pulser, using a light emitting diode, has been designed and used to investigate the resolution of a cooled surface barrier detector, which is at its theoretical optimum, limited only by the finite number of light quanta.
TL;DR: In PbTe epitaxial layers magneto-transmission and reflection measurements have been performed at temperatures between 4.2 K to 15 K and magnetic fields up to 15 T in the frequency range 20-400 cm −1.
Abstract: In PbTe epitaxial layers magneto-transmission and -reflection measurements have been performed at temperatures between 4.2 K to 15 K and magnetic fields up to 15 T in the frequency range 20–400 cm −1 The data yeild direct information on the optical constants and thus on the lattice as well as free carrier contributions to the dielectric function, and on their coupling, especially magneto-polaron pinning phenomena at the coupled plasmon-phonon frequencies.