Abstract:
A series of LaVi^xOs compounds (x=0.00, 0.02, 0.04, 0.06, 0.08) were prepeired using the
standard solid reaction. The samples were chareicterized by X-ray diffraction (XRD), fourprobe
resistivity, smd magnetic susceptibility studies.
Powder X-ray diffraction analysis indicated the formation of a single-phase sample with a
orthorhombic structure which was first found in GdFeOs (space group Pnma) . The Unit Cell
program was used for calculating lattice peirameters from XFID data. The XRD spectnim
could be indexed on a cubic lattice with Og = 2ap ~ (7.8578 to 7.9414 A). The lattice
parameter was observed to increase as the Vanadium vacancy increased.
Four-probe resistivity measurements exhibited semiconductor behavior for all sajnples
from room temperature down to 19K. The resistivity of samples increased with increasing
Vanadium vacancy. The resistivity of samples demonstrated activated conduction with an
activation energy of approximately 0.2 eV. The activation energy increased with increasing
lattice parameter.
Field cool magnetic susceptibility measurements were performed with field of 500 G from
300 K to 5 K. These measurements indicated the presence of an antiferromagnetic transition
at about 140 K. The data was fitted above Neel temperature to Ciurie-Weiss law yielding a
negative parameignetic Curie temperature. This implies that antiferromagnetic ordering is
present.
