266 research outputs found
Crystal growth and magnetic properties of equiatomic CeAl
Single crystal of CeAl has been grown by flux method using Ce-Al self-flux.
Several needle like single crystals were obtained and the length of the needle
corresponds to the [001] crystallographic direction. Powder x-ray diffraction
revealed that CeAl crystallizes in orthorhombic CrB-type structure with space
group (no. 63). The magnetic properties have been investigated by
means of magnetic susceptibility, isothermal magnetization, electrical
transport, and heat capacity measurements. CeAl is found to order
antiferromagnetically with a Nel temperature = 10K.
The magnetization data below the ordering temperature reveals two metamagentic
transitions for fields less than 20kOe. From the inverse magnetic
susceptibility an effective moment of /Ce has been estimated,
which indicates that Ce is in its trivalent state. Electrical resistivity data
clearly shows a sharp drop at 10K due to the reduction of spin disorder
scattering of conduction electrons thus confirming the magnetic ordering. The
estimated residual resistivity ratio (RRR) is 33, thus indicating a good
quality of the single crystal. The bulk nature of the magnetic ordering is also
confirmed by heat capacity data. From the Schottky anomaly of the heat capacity
we have estimated the crystal field level splitting energies of the
degenerate ground state as 25K and 175K respectively for the fist and second
excited states.Comment: Submitted to SCES -2014 Conference Proceedings (IoP conference
series); 6 pages and 5 figure
Superconductivity in non-centrosymmetric BiPd system
In this work, we establish the bulk superconductivity of a high quality
sample of monoclinic BiPd (-BiPd, space group P2) below 3.87 K by
studying its electrical resistivity, magnetic susceptibility and heat capacity.
We show that it is clean type-II superconductor with moderate electron-phonon
coupling and determine its superconducitng and normal state parameters.
Although -BiPd is a noncentrosymmetric superconductor with large
electronic heat capacity (therefore, large ), the effect of spin-orbit
splitting of the electronic bands at the Fermi level is small. This makes
little influence on the superconducting properties of -BiPd.Comment: 6 pages; 6 figures. Submitted to Phys. Rev.
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
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