Temperature dependent spin injection properties of the Ni nanodots embedded metallic TiN matrix and p-Si heterojunction

A detailed experimental investigation on magnetic field dependent electronic transport across epitaxial Ni nanoparticles embedded in metallic epitaxial TiN matrix grown on p-type (001) Si substrate heterojunction employing sequential exposure of pulsed excimer laser is reported here. The non-linear current–voltage characteristics along with good rectifying diode like behavior of the junction have been obtained in the range of 100–300 K. The ideality factor, reverse saturation current, series resistance and turn-on voltages have been estimated for the heterojunction at different operating temperatures. The dominating current transport mechanism is found to be temperature dependent tunneling assisted Frenkel–Poole type emission. A crossover from negative to positive junction magnetoresistance (JMR) has been observed at ~ 190 K (blocking temperature of the Ni nanodots). The JMR attains a peak with high positive JMR value at 250 K, the origin of which has been best explained using standard spin injection theory.