Study of Superconducting, Structural, and Thermal Properties of SnO2 Added MgB2 Bulks

A series of SnO
₂
added MgB
₂
bulk superconductors were prepared by in situ route to study the effect of oxygen doping on superconducting and structural properties of MgB
₂
. Several (MgB
₂
)
_1-x
(SnO
₂
)
_x
samples were fabricated with x ranging from 0, 3 wt%, 4 wt%, and 6 wt%. Upper critical field (B
_c2
) and irreversible field (B
_irr
) were measured by physical property measurement system. Thermal analysis was performed on the as-received SnO
₂
powder. Critical current densities (J
_cm
) were obtained at 4.2 K using magnetic measurement. X-ray diffraction results showed evidence of full SnO
₂
decomposition in all the doped bulk samples and a shift of a-axis in MgB
₂
lattice was seen. Oxygen was successfully released during heat treatment, yet no enhancement of B
_C2
or B
_irr
was seen, indicating that oxygen atoms did not end up in the host lattice. Further exploration of different processing procedures is still needed in order to get oxygen substitution on the host lattice sites.