Study of the Curie temperature of cobalt ferrite based composites for stress sensor applications

Cobalt ferrite has been shown to be an excellent candidate material for high sensitivity magnetic stress sensors due to its large magnetomechanical effect and high sensitivity to strain. However, near room temperature, the material exhibits some magnetomechanical hysteresis, which becomes negligible for temperatures of 60[degrees]C and above. Measurements indicate that doping the cobalt ferrite with silicon lowers the Curie temperature of the material. It was also found that the Curie temperature of the material depends on the fabrication and processing procedure. These results offer the possibility of decreasing the room temperature magnetomechanical hysteresis through control of the Curie temperature, thereby altering the temperature dependence of magnetic and magnetomechanical properties. Index Terms--Cobalt ferrite, Curie temperature, magnetoelastic materials, stress sensors.