Polycrystalline ZnFe2O4 thin films were deposited on Si and porous Si (PSi) substrates using Dynamic Aurora pulsed laser deposition (PLD in a magnetic field). The average grain sizes of ZnFe2O4/Si and ZnFe2O4/PSi were, respectively, 120 and 48 nm. The ZnFe2O4/PSi thin film resistance was higher than that of ZnFe2O4/Si thin film. For ZnFe2O4/Si and ZnFe2O4/PSi thin films, the sensor response for liquefied petroleum gas was measured as a function of time and temperature. The sensor response of ZnFe2O4/PSi thin film measured at 375 °C is higher than that of ZnFe2O4/Si thin film. Results showed a steep initial rise in the temperature dependence of ZnFe2O4 thin films prepared using PLD. The dependence is steeper than that reported for ZnFe2O4 powder or thick and thin films prepared using chemical processing.