Internal friction and longitudinal modulus behaviour of multiferroic PbZr_0.52Ti_0.48O₃ +Ni_0.93Co_0.02Mn_0.05Fe_1.95O_4−δ particulate composites

Abstract

Multiferroic particulate composites with composition xNi_0.93Co_0.02Mn_0.05Fe_1.95O_4−δ + (1 − x) PbZr_0.52Ti_0.48O₃ where the molar fraction x varies as 0, 0.1, 0.2, 0.3, 0.4 and 0.5 were prepared by the conventional ceramic method. The presence of two phases was confirmed by X-ray diffraction and scanning electron microscopy. The temperature variation of the longitudinal modulus (L) and the internal friction (Q⁻¹) of these particulate composites at 104.387 kHz was studied in the wide temperature range 30–420°C. The temperature variation of the longitudinal modulus (L) in each composition of these particulate composites showed two abrupt minima. One minimum coincided with the ferroelectric–paraelectric Curie transition temperature (θ_E) and the other with the ferrimagnetic–paramagnetic Curie transition (θ_M) temperature. The internal friction (Q⁻¹) measurements also showed two sharp peaks in each composition corresponding to those temperatures where the minima were noticed in the temperature variation of the longitudinal modulus behaviour. The Curie transition temperature of pure ferrite was found to be 560°C. Addition of 10% of ferrite to ferroelectric in a Magnetoelectric (ME) composite resulted in a 360°C fall in θ_M and with a further increase in ferrite content the θ_M variation was found to be very nominal. However, no significant ferroelectric Curie transition temperature shift could be noticed. This behaviour is explained in the light of structural phase transitions in these multiferroic particulate composites. These ME composites were prepared with a view to using them as ME sensors and transducers.