16 research outputs found
Single Crystal Growth of Skutterudite CoP3 under High Pressure
A new method to grow single crystals of skutterudite compounds is examined.
Using a wedge-type, cubic-anvil, high-pressure apparatus, single crystals of
CoP3 were grown from stoichiometric melts under a pressure of 3.5 GPa. Powder
x-ray diffraction and electron probe microanalysis measurements indicate that
the as-grown boules are a single phase of CoP3. The results suggest that CoP3
is a congruent melting compound under high pressure.Comment: 6pages,5 figures, J. Crystal Growth (in press
Superconductivity of MI(MII0.5, Si0.5)2 (MI=Sr and Ba, MII=Al and Ga), ternary silicides with the AlB2-type structure
Ternary silicides MI(MII0.5, Si0.5)2 (MI=Sr and Ba, MII=Al and Ga) were
prepared by Ar arc melting. Powder X-ray diffraction indicates that they have
the AlB2-type structure, in which Si and MII atoms are arranged in honeycomb
layers and MI atoms are intercalated between them. Electrical resistivity and
dc magnetization measurements revealed that Sr(Al0.5, Si0.5)2 is
superconductive, with a critical temperature for superconductivity (TC) of 4.2
K, while Ba(Al0.5, Si0.5)2 is not at temperatures ranging above 2.0 K.
Sr(Ga0.5, Si0.5)2 and Ba(Ga0.5, Si0.5)2 are also superconductors, with TCs of
5.1 and 3.3 K, respectively.Comment: 5 pages, 3 tables, 4 figure
The Influence of Neutron Irradiation on (B0.65C0.35)Ba1.4Sr0.6Ca2Cu3Oz Superconducting Phase: the Role of the Grain Edge
Using the transport and magnetization measurements the influence of neutron
irradiation at a fluence of 5x10 n cm on
(B0.65C0.35)Ba1.4Sr0.6Ca2Cu3Oz has been investigated. The neutron irradiation
was found to decrease critical temperature and transport critical current
density, increase the residual and normal state resistivity, and improve the
intragranular critical current density with 1.6x10 A/cm (at 77.3K
and in the applied field up to 160 kA m) and \Delta Mirr/\Delta Mnonirr ratio
(up to factor of 3) at highest field used for investigation. The field
dependence of this ratio, which is below the unity at very low field but higher
than 1 at high fields, correlated with the shape of the hystertic loops as well
as with the change of the transport parameters after irradiation suggests the
role of the irradiation induced effects on the grain edges. We discuss these
effects in the framework of the Bean-Livingstone surface barriers and
geometrical barriers.Comment: 12 pages, 5 figure