1,160 research outputs found
Enhanced conduction band density of states in intermetallic EuTSi (T=Rh, Ir)
We report on the physical properties of single crystalline EuRhSi and
polycrystalline EuIrSi, inferred from magnetisation, electrical transport,
heat capacity and Eu M\"ossbauer spectroscopy. These previously known
compounds crystallise in the tetragonal BaNiSn-type structure. The single
crystal magnetisation in EuRhSi has a strongly anisotropic behaviour at 2 K
with a spin-flop field of 13 T, and we present a model of these magnetic
properties which allows the exchange constants to be determined. In both
compounds, specific heat shows the presence of a cascade of two close
transitions near 50 K, and the Eu M\"ossbauer spectra demonstrate that
the intermediate phase has an incommensurate amplitude modulated structure. We
find anomalously large values, with respect to other members of the series, for
the RKKY N\'eel temperature, for the spin-flop field (13 T), for the spin-wave
gap ( 20-25 K) inferred from both resistivity and specific heat data,
for the spin-disorder resistivity in EuRhSi ( Ohm.cm) and
for the saturated hyperfine field (52 T). We show that all these quantities
depend on the electronic density of states at the Fermi level, implying that
the latter must be strongly enhanced in these two materials. EuIrSi
exhibits a giant magnetoresistance ratio, with values exceeding 600 % at 2 K in
a field of 14 T.Comment: 6 pages, 8 figure
Magnetic properties and complex magnetic phase diagram in non centrosymmetric EuRhGe and EuIrGe single crystals
We report the magnetic properties of two Eu based compounds, single
crystalline EuIrGe and EuRhGe, inferred from magnetisation, electrical
transport, heat capacity and Eu M\"{o}ssbauer spectroscopy. These
previously known compounds crystallise in the non-centrosymmetric, tetragonal,
, BaNiSn-type structure. Single crystals of EuIrGe and EuRhGe
were grown using high temperature solution growth method using In as flux.
EuIrGe exhibits two magnetic orderings at = 12.4 K, and
= 7.3 K. On the other hand EuRhGe presents a single magnetic
transition with a = 12 K. Eu M\"{o}ssbauer spectra present
evidence for a cascade of transitions from paramagnetic to incommensurate
amplitude modulated followed by an equal moment antiferromagnetic phase at
lower temperatures in EuIrGe, the transitions having a substantial first
order character. On the other hand the Eu M\"{o}ssbauer spectra at 4.2
and 9 K in EuRhGe present evidence of a single magnetic transition. In both
compounds a superzone gap is observed for the current density
[001], which enhances with transverse magnetic field. The magnetisation
measured up to 14 T shows the occurrence of field induced transitions, which
are well documented in the magnetotransport data as well. The magnetic phase
diagram constructed from these data is complex, revealing the presence of many
phases in the phase space
Effect of Thermal Annealing on Boron Diffusion, Micro-structural, Electrical and Magnetic properties of Laser Ablated CoFeB Thin Films
We report on Boron diffusion and subsequent crystallization of
CoFeB (CoFeB) thin films on SiO/Si(001) substrate
using pulsed laser deposition. Secondary ion mass spectroscopy reveals Boron
diffusion at the interface in both amorphous and crystalline phase of CoFeB.
High-resolution transmission electron microscopy reveals a small fraction of
nano-crystallites embedded in the amorphous matrix of CoFeB. However, annealing
at 400C results in crystallization of CoFe with \textit{bcc} structure
along (110) orientation. As-deposited films are non-metallic in nature with the
coercivity (H) of 5Oe while the films annealed at 400C are metallic
with a H of 135Oe.Comment: 16 pages, 6 figure
Au9+ swift heavy ion irradiation of Zn[CS(NH2)2]3SO4 crystal: Crystalline perfection and optical properties
The single crystal of tris(thiourea)zinc sulphate (Zn[CS(NH2)2]3SO4) was
irradiated by 150 MeV Au9+ swift heavy ions and analyzed in comparison with
pure crystal for crystalline perfection and optical properties. The Fourier
transform infrared and x-ray powder diffraction inferred that swift ions lead
the disordering and breaking of molecular bonds in lattice without formation of
new structural phases. High resolution X-ray diffraction (HRXRD) revealed the
abundance of point defects, and formation of mosaics and low angle grain
boundaries in the irradiated region of crystal. The swift ion irradiation found
to affect the lattice vibrational modes and functional groups significantly.
The defects induced by heavy ions act as the color centers and resulted in
enhance of photoluminescence emission intensity. The optical transparency and
band gap found to be decreased.Comment: 7 page
A study of physicochemical properties, volatile component analysis and antioxidative properties of honey
Honey samples from five different floral origins were analysed through solid phase microextraction (SPME) with objective to identify and compare their volatile organic compound profile. In addition, the levels of water, HMF, free proline, total acidity, diastase activity and sugar content have also been reported. The samples showed adequate water and HMF content. Total phenolics varied from 75.6 to 98.5mg/g, while total flavonoids were comprised between 1.86 and 4.93 mg/g, expressed as quercetin equivalents (the lowest and highest values were also found for Eucalyptus honey and neem honey, respectively). The IC50 value for DPPH has been found to be ranged from 4.97 to 9.45mg/ml. The highest DPPH RSA was found in Eucalyptus honey, followed by mustard honey and neem hone
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