A highly sensitive magnetic sensor operating at liquid nitrogen temperature and based on BPSCCO screen-printed thick film, is reported. The sensor resistance for an applied magnetic field of 100 × 10^–4T(100 gauss) exhibits an increase by 360% of its value in zero field at 77.4 K. The performance of the sensor in presence of magnetic field, the hysteretic features and the effect of thermal cycling, has been discussed.

The characteristics of a magnetic sensor, based on the non-linear electromagnetic response of the weak links present in polycrystalline BPSCCO superconductor are reported. The second harmonic response of the sensor in an alternating magnetic field at 40 kHz and at 77 K being a strong linear function of low d.c. field is utilized for magnetic field sensing. The noise limited resolution of the sensor is found to be 3.16 × 10^-9 T/√ Hz for 𝐻_a.c. = 16 G and frequency 40 kHz. The magnetic sensor has been applied for non-destructive detection of various types of flaws in ferromagnetic plates and also for detection of small magnetic inclusions in a non-magnetic matrix. Our results suggest that the 2𝑓 response based BPSCCO superconductive magnetometer has potential for its appication in the area of non-destructive evaluation of defects in ferromagnetic materials.

Spray-pyrolysed zinc oxy-sulphide Zn(O,S) has been doped with varying concentrations of indium (In) toimprove its electrical and optical properties for possible application as buffer layer in thin film solar cells. The In-dopingin Zn(O,S) is found to change the electron carrier concentration from 10$^{19}$ to 10$^{18}$ cm$^{−3}$ and a subsequent annealing in argon atmosphere is found to improve its electrical conductivity. Moreover, annealing in air atmosphere reduces the carrier concentration to a range of 10$^{13}$–10$^{15}$ cm$^{−3}$ making it useful as a buffer layer. The reduction in degeneracy of In-doped Zn(O,S) is desirable for its application as buffer material, whereas annealing in argon makes it suitable as electron membrane (window layer) in thin film solar cell.