The Cr3+ substituted Mg-Cd ferrite powder was synthesized by standard ceramic route. The crystal structure and formation of spinel ferrite were examined by XRD and FT-IR techniques. The particle size has been estimated using Debye-Scherrer equation. All the peaks in the XRD pattern are narrow which means that particles are to nano range. The structure inferred from the XRD and FT-IR is cubic. The samples were tested for LPG gas. The sensitivity was measured at various temperatures. The sensitivity was found to maximum at 3000C. The response time and recovery time was also measured.
