Browsing School of Physics by Date of Publication
Now showing items 21-40 of 2104
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Near-infrared dye having a large ultrafast third-order susceptibility
(1986)Efficient degenerate four-wave mixing of 160-psec infrared light pulses at ? = 1.064 ?m in solutions of a new dye that absorbs between 1.0 and 1.6 ?m is reported. A Kerr-like third-order susceptibility of X(3)xyyx = 8 ? ... -
Optical phase conjugation In a soluble polymer
(1986)Degenerate four-wave mixing of picosecond light pulses in polydiacetylene dissolved in toluene has been observed. Phase conjugate reflectivities of over 100% were obtained. The origin of the non-linear interaction was found ... -
Base-specific photocleavage of DNA induced by nanosecond U.V. pulsed laser radiation or methylene blue sensitisation
(1987)Excitation of DNA in neutral solution either with short-duration, intense pulses of excimer laser (248 nm) radiation or with low intensity red-ligh (633 nm) sensitisation by methylene blue causes cleavage of the DNA backbone ... -
Magnetic properties of iron-rich Fe-Zr glasses
(American Physcial Society, 1987)A systematic study of the magnetic properties of melt-spun amorphous FexZr100-x alloys with 88?x?93 using Mossbauer and magnetization measurements has established the magnetic phase diagram. The ordering temperature Tc ... -
Determination of the PIn antisite structure in InP by optically detected electron-nuclear double resonance
(American Physical Society, 1987)Optically detected electron-nuclear double resonance (ODENDOR) is reported for the PIn antisite in p-type InP. In both electron-irradiated and as-grown samples, ENDOR signals from the four nearest P neighbors and the next ... -
Kohlraush thermal relaxation in a random magnet
(American Physical Society, 1987)Specific-heat measurements on amorphous FexZr100-x (x=90 and 92) by a thermal relaxation method reveal a temperature decay of the form T(t)=T0+T exp[-(t/)] below 20 K, where the alloys are asperomagnetically ordered. 0.5 ... -
Resonant third-order hyperpolarizabilities of large organic molecules
(1987)Resonant degenerate four-wave mixing in a number of infrared-absorbing dyeswas studied with 160-psec pulses at 1.064 ?m. Hyperpolarizabilities in the range of 10-44 to 10-42 V-2 m5 were observed. A theoretical model based ... -
Direct measurement of exchange as a function of separation for discrete donor-acceptor pairs in ZnSe
(American Physical Society, 1988)We describe optical detection of magnetic resonance for 17 well-resolved discrete zinc interstitial donor-zinc vacancy acceptor pairs of varying separation in ZnSe. For most of the pairs, microwave transitions are detected ... -
Dependence of core-level photoemission spectra on overlayer growth mode: Al on InP(110)
(1988)The adsorption of Al overlayers on the clean, cleaved InP(110) surface has been studied, with the InP substrates at room and low (120 K) temperatures, using synchrotron radiation excited soft-x-ray photoemission spectroscopy. ... -
H-alpha emission lines in high-redshift quasars
(1989)Infrared spectra have been obtained of the H-alpha lines in 18 medium- to high-redshift QSOs and optical spectra taken nearly simultaneously to measure the strong UV line. It is found that the H-alpha line is redshifted ... -
Optical detection of electron-nuclear double resonance for a donor in oxygen-doped GaP
(1989)Optical detection of electron-nuclear double resonance (ODENDOR) has been used in a study of an optically detected magnetic resonance spectrum previously assigned to the shallow effective-mass-like 1S(E) state of the ... -
Magnetic properties of iron-rich Fe-Sc glasses
(American Physical Society, 1989)Amorphous FexSc100-x alloys with x=89, 90, and 91, prepared by melt spinning, exhibit a single sharp spin-freezing transition at 100 3 K to an asperomagnetic state. The average Fe57 hyperfine field at 4.2 K is 22.7 T. ... -
Electronic properties of Sr14Cu24O41
(American Physical Society, 1989)Crystals of orthorhombic Sr14Cu24O41 are semiconducting, with an activation energy of 0.18(2) eV for conduction along c, the direction lying parallel to both the (Cu2O3) planes and the (CuO2) chains. The magnetic susceptibility ... -
Plasma formation in a pseudospark discharge
(IEEE, 1989)Unique features associated with the hollow cathode recess in a pseudospark discharge have been identified from streak camera observations. A plasma is observed to form in a highly localized region immediately behind the ... -
Measurement of electron temperature and state of ionization in laser-produced plasmas by use of dielectronic satellite lines
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Magnetization of a Dy(Fe11Ti) single crystal
(American Physcial Society, 1990)Magnetization curves have been measured in the temperature range from 4.2 to 300 K along the [100], [110], and [001] directions of a Dy(Fe11Ti) single crystal in fields up to 7 T. The magnetic moment is along [100] below ... -
Giant transverse hysteresis is an asperomagnet
(American Physical Society, 1990)Comparison of the magnetoresistance of amorphous thin films of Tb80U20 and the nonmagnetic analog Y80U20 reveals hysteresis for the terbium alloy, which extends to fields in excess of 8 T at 4.2 K. Hysteresis is found in ... -
Perpendicular magnetic-anisotropy in iron films produced by laser chemical vapor-deposition of FE(CO)5
(IEEE, 1990)Uniform thin films of polyc r y s t a l l i n e a -iron are obtained by decomposing a stream of Fe(C0)s in a flow reactor using 193 nm ArF excimer laser pulses. The films are optically flat and 2.6 pm thick, but have ... -
Coercivity mechanism of melt-spun Sm(Fe11Ti)
(IEEE, 1990)Hysteresis loops of randomly oriented grains with uniaxial anisotropy were computed on the basis of an array of 27 Wigner-Seitz cells representing crystallites which interact by exchange coupling at the grain boundaries. ... -
Observation of nonradiative energy transfer in the excitation of Nd3+ in GaP
(American Physical Society, 1990)We have carried out luminescence-excitation measurements on a Nd3+ complex in GaP in the range 1.5?2.2 eV to determine the mechanisms by which the internal Nd3+ luminescence is generated. At low temperatures we observe ...