1,772 research outputs found
Superconductivity at 5.2 K in ZrTe3 polycrystals and the effect of Cu, Ag intercalation
We report the occurrence of superconductivity in polycrystalline samples of
ZrTe3 at 5.2 K temperature at ambient pressure. The superconducting state
coexists with the charge density wave (CDW) phase, which sets in at 63K. The
intercalation of Cu or Ag, does not have any bearing on the superconducting
transition temperature but suppresses the CDW state. The feature of CDW anomaly
in these compounds is clearly seen in the DC magnetization data. Resistivity
data is analysed to estimate the relative loss of carriers and reduction in the
nested Fermi surface area upon CDW formation in the ZrTe3 and the intercalated
compounds.Comment: 5 pages, 8 figure
Metamagnetic and electronic transitions in charge-ordered Nd0.50Ca0.47Ba0.03MnO3 manganite
The ABO3 type charge-ordered antiferromagnetic Nd0.50Ca0.50MnO3 (NCMO)
manganite is doped at A-site by 3 % of Ba2+ for Ca2+. The resulting system,
Nd0.50Ca0.47Ba0.03MnO3 (NCBMO), is studied for the effects of Ba doping on the
magnetic and electronic properties. On application of magnetic field to NCBMO,
strongly correlated successive sharp metamagnetic and electronic transitions
are observed from antiferromagnetic-insulating to ferromagnetic-metallic state
at 2.5 K. The critical magnetic field (Hc) required for metamagnetism is found
to reduce drastically from 15 T for undoped NCMO to 3 T for NCBMO. On
increasing the temperature, the Hc of NCBMO passes through a minimum. This
behavior of Hc of NCBMO contrasts to that of NCMO. The results are discussed in
context of A-site cation disorder and size
Residual resistivity ratio and its relation to the positive magnetoresistance behavior in natural multilayer LaMn2Ge2; relevance to artificial multilayer physics
Results of low temperature magnetoresistance () and
isothermal magnetization (M) measurements on polycrystalline ferromagnetic (T_C
close to 300 K) natural multilayers, LaMn_{2+x}Ge_{2-y}Si_y, are reported. It
is found that the samples with large residual resistivity ratio,
, exhibit large positive magnetoresistance at high
magnetic fields. The Kohler's rule is not obeyed in these alloys. In addition,
at 4.5 K, there is a tendency towards linear variation of
with magnetic field with increasing ); however, the field
dependence of does not track that of M, thereby suggesting
that the magnetoresistance originates from non-magnetic layers. It is
interesting that these experimental findings on bulk polycrystals are
qualitatively similar to what is seen in artificially grown multilayer systems
recently.Comment: 5 pages, 3 figures, separate figures. This work is a follow-up of our
earlier paper in APL, Ref. : APL Vol 71, pp 2385 (1997
An insight into spin-chain magnetism through Moessbauer spectroscopic investigations in Eu-doped Ca3Co2O6 and Ca3CoRhO6
We report the results of 151Eu Moessbauer effect and magnetization
measurements in the Eu-doped Ca3Co2O6 and Ca3CoRhO6, which are of great current
interest in the fields of spin-chain magnetism and geometrical frustration. We
find that there is a pronounced increase in the line-width of the Moessbauer
spectra below a certain characteristic temperature which is well-above the one
at which three-diensional ordering features set in. This unusual broadening of
the spectra indicates the existence of a characteristic temperature in these
'exotic' magnetic systems, attributable to the onset of incipient
one-dimensional magnetic order. This is inferred from an intriguing correlation
of this characteristic temperature with the paramagnetic Curie temperature (a
measure of intrachain coupling strength in these cases)
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