Christos Christides

Christos Christides
University of Patras | UP · Department of Computer Engineering and Informatics

Professor

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99
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Publications

Publications (99)
Article
A comparative study of dielectric, specific heat, and magnetic properties has been carried out between bulk Y3Fe5O12 (YIG) samples which display different behavior regarding the dielectric and ac-susceptibility spectra. Experimental results are presented from two categories of YIG samples (called sample-A and sample-B). Sample-A exhibits zero imagi...
Article
Full-text available
A nanogranular thin film structure with concentration Co(c=0.2)Bi(1-c), and thickness 25 nm, exhibits: (i) a progressive crossing of Hall coefficient RH(B) curves from negative at lower fields to positive sign at higher fields between 5K and 200K, and (ii) the perpendicular magnetoresistance (PMR), ρ⊥(B,T)/ρ⊥(B=0,T), curves are separated, exhibitin...
Conference Paper
In this paper we investigate the influence of dielectric and magnetic losses of an Epoxy bonded Yttrium Iron Garnet (YIG-Epoxy) composite substrate on the performance of a reconfigurable microstrip patch antenna. The antenna under investigation is a microstrip patch antenna printed on a 60/40 w/w% YIG-Epoxy composite substrate and controlled by an...
Article
A nanogranular thin film structure with concentration Co(c = 0.8)Bi(1 − c), and thickness about 100 nm, exhibits one order of magnitude increase of the anomalous Hall coefficient RS (with an absolute value of |RS| = 1.43 μΩ cm at 300 K), relative to that observed in pure Co thin films. This may provide evidence that a Giant Hall Effect (GHE) contri...
Article
Magnetoconductivity (MC), Delta sigma(B), and Hall coefficient, R-H(B), measurements have been performed in polycrystalline thin films of Bi(15nm), Bi(10nm)/Co(1nm)/Bi(10nm) trilayer and [Co(0.7nm)/Bi(2nm)](10) multilayer, grown by magnetron scattering. The temperature dependence of R-H(B) curves reveal the existence of a second conduction channel...
Article
Full-text available
A series of Co-Bi thin films with Co concentrations c=0, 0.05, 0.2, 0.26, 0.3, 0.333, 0.375, 0.545, were grown by magnetron sputtering on Si(100)/SiNX substrates. Resistivity measurements at zero field (ρxx) as a function of temperature-T exhibit an exponential variation with T in the region of 240K<T<300K. The Hall coefficient as a function of Co...
Article
The artificial control of grain-boundary resistance and its contribution to magnetic and magneto-transport properties in [Co(3nm)/Bi(2.5nm)/Co(3nm)]Ir20Mn80(12nm) thin films that exhibit exchange bias is studied. Transverse magnetoresistance (MR) loops exhibit a negative MR in thin films grown by magnetron sputtering on Si/SiNx(100nm) substrates. T...
Article
The magnetotransport properties of [Co(1nm)/Bi(2.5nm)]10 multilayers are examined in line structures prepared by magnetron sputtering and a two-step microfabrication process. At 10K the transverse magnetoresistance (MR) in [Co(1nm)/Bi(2.5nm)]10 line structures exhibits a ΔR/R=80% effect, and a change of the anomalous Hall effect (AHE) voltage equal...
Article
The present study examines the artificial control of grain-boundary resistance and its contribution to the magneto-transport properties of [Co(1 nm)/Bi(2.5 nm)]n (n=10 or 20) line structures on the Si(0 0 1)/SiNx substrate. Conventional patterning and deposition processes are applied for the fabrication of a device that consists of five-line struct...
Article
The dependence of magnetoresistance (MR) on the magnetization reversal processes was studied in Co and NiFe line structures with pads. Conventional patterning and deposition processes are applied for the fabrication of a device that consists of five-line structures with a line-width of 2μm. It is demonstrated that the large asymmetry of AMR loops i...
Article
We have measured the low-energy neutron inelastic-scattering (NIS) spectra of superconducting Na2RbC60 in the temperature range 50–350 K. Well-defined librational peaks are observed at 50 K at 2.83(17) meV (FWHM = 1.7(5) meV). They soften and broaden with increasing temperature. Their behaviour mimics that found in solid C60 and differs markedly fr...
Article
The vibrational spectrum of saturation-doped insulating Rb6C60 has been measured by inelastic neutron scattering at nonzero momentum transfer in the energy range (5 ÷ 200) meV at 20 K. The two lowest-energy fivefold degenerate Hg modes sharpen substantially in comparison with superconducting K3C60, acquiring comparable widths to those found in pris...
Article
Metal–insulator-like (MI) behavior in semi-metallic Bi-nanowires and single crystals indicate that semimetals exhibit a combination of unusual features of metal-insulating behavior which are accompanied by anomalously high magnetoresistance. These effects make semi-metallic Bi a potential candidate for use in magneto-electronic devices. The present...
Article
Full-text available
Complementary x-ray synchrotron radiation diffraction (XRD) and resonant scattering (RXS) measurements were performed at the MnK -edge between 10 and 300K in order to analyze the effect of epitaxial strain and tetragonal lattice distortions on the exchange bias (EB) mechanism observed in [La2/3Ca1/3MnO3(FM)/La1/3Ca2/3MnO3(AF)]15 multilayers below a...
Article
The effect of the metallic antiferromagnet (AF) γγ-FeMn and the AF-semiconductor NiO alloys on the polarity of Hall resistivity loops is examined in perpendicularly biased [Pt (2 nm)/Co (0.4 nm)]1515/AF (3 nm)/[Co (0.4 nm)/Pt (2 nm)]1515 multilayers.
Article
The effect of the metallic antiferromagnet (AF) γ-FeMn and the AF-semiconductor NiO alloys on the polarity of anomalous Hall resistivity loops is examined in perpendicularly biased [Pt(2 nm)/Co(0.4 nm)]15/AF(3 nm)/[Co(0.4 nm)/Pt(2 nm)]15 (AF = NiO, FeMn) multilayers. The Hall resistivity exhibits negative polarity for AF = NiO and positive polarity...
Article
High-precision crystal structure parameters have been determined from Rietveld refinement of high-resolution neutron powder diffraction data in Nd 3 (Fe, Ti) 29 and Nd 3 (Fe, Ti) 29 N x intermetallics. The construction of the corresponding Wigner–Seitz (WS) polyhedra has revealed that some 12-fold (group-A) environments and the 14-fold (group-D, du...
Article
1 H nuclear-magnetic-resonance and magnetization measurements have been performed in the molecule-based solid Cu(btaO) 2 (MeOH) n btaOH stands for 1-hydroxybenzotriazolate as a function of temperature. The compound exhibits a critical transition at T c 5.7 K from a high-temperature paramagnetic phase to a low-temperature magnetic phase characterize...
Article
The commercial MagScan X-Y scanning system, that uses either a Hall-probe or a giant magnetoresistance (GMR) bridge sensor, has been used to perform fast magnetic field mapping of ring-shaped permanent magnets. Maps of the three magnetic field components have been obtained separately from both types of sensors. Comparison between these maps has all...
Article
111 oriented Co(1 nm)/Au(2.5 nm) 30 multilayers exhibit a strong thermal variation of the magnetoresistive MR signal between 5 and 280 K, that consists of field-direction dependent giant GMR and anisotropic magnetoresistance AMR contributions. Both, isothermal magnetization and the MR loops reveal the appearance of a canted magnetic state that acco...
Article
Full-text available
1H NMR line-shape measurements have been performed in the linear chain molecule-based ferrimagnet [MnTFPP][TCNE]⋅xPhMe (TFPP=tetrakis(4-fluorophenyl)porphinato; TCNE=tetracyanoethylene) as a function of temperature. Hyperfine shifts of opposite sign were observed indicating the presence of two oppositely hyperfine couplings, predominantly between t...
Article
Full-text available
Strained epitaxial bilayers and multilayers consisting of La1−xCaxMnO3 ferromagnetic (FM) layers (x=0.33, 0.4) and La0.33Ca0.67MnO3 antiferromagnetic (AF) layers were grown on (001)LaAlO3 to study the evolution of exchange coupling interactions. The epitaxy was revealed by conventional and high resolution electron microscopy. An out-of-plane lattic...
Article
Two series of exchange-coupled [La1−xCaxMnO3(4nm)/La1−yCayMnO3 (4nm)]15 multilayers (one with constant y=0.67 while x=0.33, 0.4, 0.48, and the other with constant x=0.4 while y=0.52, 0.75) were used to investigate the effect of the field cooling on both, the exchange-biasing field (HEB) and the coercivity (Hc). Large magnetothermal irreversibilitie...
Article
We demonstrate the magnetic-field distribution of the pure vortex state in lightly doped (formula presented) powder samples, by using (formula presented) nuclear magnetic resonance in magnetic fields of 23.5 and 47 kOe. The magnetic-field distribution at (formula presented) is Al-doping dependent, revealing a considerable decrease of anisotropy in...
Article
In exchange-coupled ferromagnetic/antiferromagnetic La0.60Ca0.40MnO3(FM)/La0.33Ca0.67MnO3(AF) multilayers the magnetization reversal mechanism is probed by magnetic viscosity and remanence measurements below (5 K) and above (80 K) the blocking temperature TB=70 K. The magnetic relaxation follows the ln(t) behavior at 5 K, which is a universal featu...
Chapter
This chapter delineates magnetotransport properties of ultrathin metallic multilayers. In man-made devices, where the information is transmitted and processed in electrical form through the transport of electrons, a sensor is defined as “a device that receives a signal or a stimulus and responds with an electrical signal.” The stimulus is the quant...
Article
We demonstrate the magnetic-field distribution of the pure vortex state in lightly doped Mg1-xAlxB2 (x<~0.025) powder samples, by using 11B nuclear magnetic resonance in magnetic fields of 23.5 and 47 kOe. The magnetic-field distribution at T=5 K is Al-doping dependent, revealing a considerable decrease of anisotropy in respect to pure MgB2. This r...
Article
Full-text available
Compositionally modulated structures consisting of La1-xCaxMnO3 ferromagnetic (FM) layers (x=0.33, 0.4, 0.48) and La1-yCayMnO3 antiferromagnetic (AF) layers (y=0.52, 0.67, 0.75) were grown on (001)LaAlO3 by pulsed laser deposition. Thermomagnetic and isothermal magnetic, magnetotransport measurements reveal an exchange biasing mechanism below a blo...
Article
Full-text available
The temperature dependence of the magnetic field distribution in the mixed superconducting phase of randomly oriented MgB$_2$ powder was probed by $% ^{11}$B NMR spectroscopy. Below the temperature of the second critical ($B_{% {c2}}$) field, $T_{{c2}}\approx 27$K, our spectra reveal two NMR signal components, one mapping the magnetic field distrib...
Article
The R3(Fe,V)29 compounds, with R=Dy, Er, Y, and the Gd3(Fe, TM)29, with TM=Ti and V, after heat treatment between 1123 and 1233 K form disordered structures that belong in the CaCu5 type family. The compounds with R=Y or Dy and TM=V crystallize in a disorder CaCu5 structure type (space group (S.G.): P6/mmm with cell dimensions a=4.8769(1) Å, c=4.17...
Article
The magnetic structural and magnetotransport properties are studied in a series of [La2/3Ca1/3MnO3/La1/3Ca2/3MnO3]15 multilayers prepared by pulsed laser deposition. The La2/3Ca1/3MnO3 layers are ferromagnetic (FM) and La1/3Ca1/3MnO3 layers are antiferromagnetic (AF). The structural compatibility of the AF and FM layers permits coherent growth that...
Article
Full-text available
The effect of annealing on the microstructure of sputter-grown Co/Au multilayers with (111) texture is studied by means of x-ray diffraction (XRD) and spin-echo 59Co nuclear magnetic resonance (NMR) spectroscopy. Both XRD and NMR spectra exhibit drastic changes after annealing at 350°C, revealing a transformation from Co layering in the as-made mul...
Chapter
Earlier studies [1,2] in giant-magnetoresistance (GMR) Co/Cu multilayers (MLs), that exhibit low-hysteresis at about 290 K, have shown a dramatic increase of hysteresis below 100 K. These results imply that, while the activation energy for magnetization reversal is reduced by a decrease of Co layer thickness [1] (tCo) or by Co-Cu alloying [2], it r...
Article
Three classes of giant magnetoresistance Co(1 nm)/Cu(2.1 nm) multilayers were sputter grown with different microstructures in respect to grain size and interface roughness, depending on deposition conditions. Magnetization and current in-plane giant-magnetoresistance (GMR) isothermal loops reveal an unusually high increase of coercivity from 280 do...
Article
Magnetic field mapping measurements were performed using commercial high-Tc superconducting quantum interference device (SQUID) sensors. The sensors are incorporated in a fully computerized scanning system and were found to be operative only when encased inside a double-layer mu-metal shield. This allowed us to measure signals of the order of 0.5 n...
Article
Full-text available
Compositionally modulated structures consisting of La2/3Ca1/3MnO3 ferromagnetic (FM) layers and La1/3Ca2/3MnO3 antiferromagnetic (AF) layers, with layer thickness 1.5 nm ⩽tFM,tAF⩽6 nm, were grown on (100)LaAlO3 by pulsed laser deposition. Thermomagnetic and isothermal magnetic measurements reveal an exchange-biasing mechanism with the same blocking...
Article
The growth of Co/Au multilayers on Si(001)/SiNx is investigated by means of transmission and high resolution electron microscopy (TEM-HREM) as a function of Co layer thickness. Although there is an amorphous SiNx buffer layer between the substrate and the multilayer, the growth of alternative Co and Au layers exhibit strong texture with the (111) p...
Chapter
In mixed valence manganites a large negative magnetoresistance (MR), termed colossal magnetoresistance [1] (CMR), can be obtained due to a metal-insulator transition at the ferromagnetic Curie point [2]. However little progress has been made towards using these materials in applications, mainly due to the strong temperature dependence of the CMR ef...
Article
We present magnetic field mapping measurements performed with commercial high-Tc superconducting quantum interference device (SQUID) sensors. Our aim was to make an initial assessment of the capabilities of our commercial high-Tc sensors (and of the entire system incorporating them) under zero applied magnetic field. This allowed us to measure sign...
Article
A series of Co/Au multilayers, which exhibit (111) texture and low-field giant magnetoresistance (GMR), were examined with spectroscopic ellipsometry (SE) in a range of Co layer thicknesses (tCo). The obtained optical dielectric functions show a systematic variation with increasing tCo. Analysis of the optical transitions reveals nonmonotonic varia...
Article
14N electron spin echo envelope modulation (ESEEM) and 1H nuclear magnetic resonance (NMR) techniques have been employed in order to measure the unpaired electron spin density of amino nitrogens and CH3 protons, in the low temperature ferromagnetic state of solid TDAE-C60. Well resolved 14N ESEEM patterns were obtained for the first time below 9 K,...
Article
Low hysteresis, giant magnetoresistance (GMR) sputtered Co/Cu multilayers were employed in a 2×4 array of sensing elements. Patterning was performed by optical lithography, using the lift-off technique. To assess the applicability of this sensor, magnetic field mapping of a ring-magnet was performed with a computer controlled scanning system and th...
Article
A series of [La2/3Ca1/3MnO3(Λ/2)/La1/3Ca2/3MnO3(Λ/2)]15 multilayers, with bilayer thicknesses Λ between 2 and 32 nm, has been prepared by pulsed laser deposition. The study of their magnetic and magnetotransport properties reveals the presence of an exchange-biasing mechanism at low temperatures. Zero-field-cooling and field-cooling magnetic measur...
Article
Magnetotransport and magneto-optical (MO) results on sputtered Co/Au multilayers at 300 K are reported. The thickness of Co layer was fixed at while that of Au, tAu, varied between 2.2 and 4 nm. Two giant-magnetoresistance (GMR) maxima were observed for tAu≈2.4 and 3.9 nm. For the coercive field and switching fields are 7 and ±30 Oe, respectively....
Article
Full-text available
A series of [ La <sub> 2/3 </sub> Ca <sub> 1/3 </sub> MnO <sub> 3 </sub> /La <sub> 1/3 </sub> Ca <sub> 2/3 </sub> MnO <sub> 3 </sub>]<sub>15</sub> multilayers, with bilayer thicknesses between 2 and 32 nm, has been prepared by pulsed laser deposition. The study of their magnetic and magnetotransport properties reveals, for the first time in this ca...
Article
Full-text available
Magnetron sputtered Co/Cu and Co/Au multilayers (MLs) with low-field giant magnetoresistance were grown on SiNx underlayers. Spin-echo 59Co nuclear magnetic resonance (NMR) spectra reveal an fcc Co layer stacking for the Co/Cu multilayers whereas the Co/Au spectra exhibit a unique profile that cannot be assigned to any of the known bulk crystalline...
Article
Full-text available
Results of magnetic, medium-resolution neutron diffraction and small-angle neutron scattering (SANS) measurements on a polycrystalline LuFe10Mo2 intermetallic alloy show that ferromagnetic (FM) interactions exist between 5 and 325 K, but finite magnetic spin correlations emerge in the examined temperature range. It is observed that in zero applied...
Article
The anisotropic nature of the resistivity of magnetic multilayers under a parallel or perpendicular applied magnetic field is addressed by magnetoresistivity and hysteresis loop measurements. It is shown that the observation of anisotropic magnetoresistance (AMR) at 80 K can provide straightforward information on the magnetic properties of successi...
Article
Full-text available
In this work, we have studied the crystal and magnetic structure of fully deoxygenated using neutron powder diffraction data. Rietveld profile refinement confirmed the presence of removable oxygen y within the Cu(1) layers. While for the fully oxygenated sample the space group describes the crystal structure adequately, for the deoxygenated sample...
Article
The crystal and magnetic structures of the perovskite YBaCuFeO5+δ have been studied in the temperature range T = 4.2-300 K by powder neutron diffraction. In addition to the antiferromagnetic ordering transition at TN = 442 K, a commensurate-incommensurate magnetic transition is detected at T′N = 190 K. Below this temperature, two sets of satellite...
Article
The high-Tc phase (110 K) of the Bi2-xPbxSr2Ca2Cu3Oy system has been synthesised and the role of Bi/Pb substitution has been studied extensively using X-ray diffraction studies, electrical resistivity and magnetisation measurements and scanning electron microscopy. It was found that the best results were obtained for x=0.2-0.3 and that a 'step sint...
Article
Full-text available
A variety of magnetic phase transitions have been observed for all the RFe10Mo2 compounds from AC and DC magnetic measurements in the temperature range between 4.2 and 300 K. The alloys with R = Nd, Tb and Dy exhibit spin reorientation transitions and with R = Ho, Er and Tm some unidentified magnetic phase transitions occur which are accompanied by...
Article
Magnetotransport and magneto-optical (MO) results on sputtered Co/Au multilayers at 300 K are reported. The thickness of Co layer was fixed at tCo=1 nm while that of Au, tAu, varied between 2.2 and 4 nm. Two giant-magnetoresistance (GMR) maxima were observed for tAu~2.4 and 3.9 nm. For tAu~2.4 nm the coercive field and switching fields are 7 and +/...
Article
La2/3Ca1/3MnO3 doped with Fe were studied by Mössbauer spectroscopy and neutron powder diffraction. The Mössbauer spectra (MS) reveal that Fe substitutes for Mn as Fe3+ (S=5/2) and is antiferromagnetically coupled to the Mn host lattice. The magnetic behavior, from the neutron diffraction data, is that of a typical 3D Heisenberg ferromagnet. The te...
Chapter
The study of the magnetic properties of mixed valence manganese perovskites dates back almost 50 years [1–2]. The existence of competitive ferromagnetic (FM) double-exchange [3] and antiferromagnetic (AF) superexchange interactions, which are very sensitive to the structural parameters and the degree of doping, results in a very rich magnetic phase...
Article
A series of [La2/3Ca1/3MnO3(Λ/2)/La 1/3Ca2/3MnO3(Λ/2)]15 multilayers, with bilayer thicknesses Λ between 2 and 32 nm, has been prepared by pulsed laser deposition. The study of their magnetic and magnetotransport properties reveals the presence of an exchange-biasing mechanism at low temperatures. Zero-field-cooling and field-cooling magnetic measu...
Article
Full-text available
A series of magnetron-sputtered [Co(1 nm)/Au(tAu)]30 multilayers (MLs) has been deposited on Si(100) substrates covered with a 100 nm thick SiNx buffer layer. The samples were examined with x-ray diffraction (XRD), magnetotransport (MR), isothermal magnetization (M-H), and transmission electron microscopy (TEM) measurements. The quality of the inte...
Article
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A series of {[Co(tCo)/Cu(2.1 nm)]30/Co(tCo)}30 multilayers have been deposited under specific magnetron sputtering deposition conditions that lead to giant magnetoresistance (GMR) curves with technological interest. X-ray reflectivity, magnetic, magneto-transport, and spectroscopic ellipsometry measurements were used together to examine the depende...
Article
Full-text available
Three different classes of [ Co/1.1 nm/Cu/2.1 nm ]<sub>30</sub> multilayers were grown by magnetron sputtering deposition. The effect of magnetostatic interactions on the giant-magnetoresistance (GMR) and magnetic properties are examined in relation to the induced changes in the film microstructure as it is varied by: (i) the substrate surface roug...
Article
Full-text available
Enhanced planar Hall voltage changes were measured for a cross-diagonal current– voltage configuration in [Co (1.2 nm)/Cu (0.7 nm)] 30 multilayers deposited on square 1 cm 2 Si(100) substrates by magnetron sputtering. A (V /V peak) = 4000% voltage maximum change is observed with an I ext = 1 mA current flow along one diagonal of the square and the...
Article
We studied the crystal and magnetic structure of the oxygen deficient perovskite YSrCuFeO5+y. The structure was refined from neutron powder diffraction data by assuming both substitutional and displacement disorder. Three-dimensional (3D) antiferromagnetism with TN = 400 ± 10 K occurs and all the magnetic peaks were indexed with two propagation vec...
Chapter
X-ray diffraction, magneto-transport and hysteresis loop measurements in as deposited (Ni81Fe19/Ag) multilayers provide information for the influence of interlayer stress on the observed GMR effect. A ferromagnetic coupling accompanied with oscillations of Hc and Mr at 5 K is observed as a function of Ag (tAg) but not with NiFe (tf) layer thickness...
Article
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Superstructure refinement analyses of x‐ray‐diffraction data, magnetotransport, and hysteresis loop measurements were performed in Ni 81 Fe 19 /Ag ultrathin multilayers. A ferromagnetic coupling and oscillations of coercivity H c and residual magnetization M r at 5 K have been observed as a function of Ag layer thickness. The observed residual stre...
Article
Magnetic phase transitions related to spin-glass-like behavior were detected by ac-susceptibility measurements in LuFe12-xMox alloys with x > 1.8. Dc-magnetic measurements have been used to determine the saturation magnetization Ms and the ferromagnetic-like transition temperatures Tc, as a function of Mo concentration. A linear variation of the la...
Article
Moessbauer measurements performed between 5 and 300 K on polycrystalline powder of an iron-carbonyl derivative of C[sub 60] reveal two inequivalent iron sites. The first site displays a quadrupole split doublet at all temperatures, assigned to an [(Fe(CO)[sub 4])[sub x]([eta][sup 2]-C[sub 60])] adduct (x unknown). This iron site presents an S = O s...
Article
The fullerenes represent a new new molecular form of carbon which has remarkable physico-chemical properties, making them desirable as components in new materials. An understanding of the principles for the preparation of both pure buckminsterfullerene (C60) derivatives of known addition number and pattern, and C60-containing materials of known com...
Article
The fullerenes represent a new molecular form of carbon. Their remarkable physico-chemical properties make them desirable as components in new materials, and in order to exploit these properties it is necessary to understand the principles for the preparation of both pure buckminsterfullerene (C60) derivatives of known addition number and pattern,...
Article
The magnetic and crystal structures of the oxygen-deficient layered perovskite YBaCuFeO[sub 5+[delta]] have been determined with powder neutron diffraction methods. It crystallizes in the noncentrosymmetric tetragonal space group P4mm with a = 3.870(2) [angstrom] (at room temperature). Structural motifs of corner-sharing severely elongated CuO[sub...
Article
Full-text available
The crystal structure of superconducting Na(2)CsC(60) was studied by high-resolution powder neutron diffraction between 1.6 and 425 K. Contrary to the literature, the structure at low temperatures is primitive cubic [See equation in the PDF file], isostructural with pristine C(60). Anticlockwise rotation of the C(60) units by 98 degrees about [111]...
Article
Full-text available
We report the results of neutron-diffraction and low-energy neutron-inelastic-scattering experiments on high-purity solid C70 between 10 and 640 K. Thermal hysteresis effects are found to accompany structural changes both on cooling and on heating. The observed diffuse scattering intensity does not change with temperature. At 10 K broad librational...
Article
The crystal structure of superconducting Na[sub 2]CsC[sub 60] was studied by high-resolution powder neutron diffraction between 1.6 and 524 K. Contrary to the literature, the structure at low temperatures is primitive cubic (Pa3), isostructural with pristine C[sub 60]. Anticlock