Electrical properties and microwave dielectric behavior of holmium substituted barium zirconium titanate ceramics

Abstract Structural, microwave dielectric and electrical properties of (Ba 1 −  x Ho x )(Zr 0.52 Ti 0.48 )O 3 with the mole fraction of x  = 0.1 and 0.2 have been investigated. The results obtained from these studies indicate the substitution of Ho-ions within the barium zirconium titanate. The microwave dielectric parameters were measured using the time domain reflectometry (TDR) method in the frequency range 10 MHz to 30 GHz. The dielectric constant as a function of temperature exhibited diffuse phase transition behavior for x  = 0.1 Ho-substituted ceramics accompanied with lower value of dielectric constant. Complex impedance ( Z ∗ ) planes show frequency dependent behavior as the response for the grain resistance mechanisms. This mechanism has been represented by an RC equivalent circuit. Our results along with the observation of negative temperature coefficient of resistance (NTCR) upon Ho 3+ ions substitution clearly suggest the design and development of novel microwave dielectric resonators based on barium zirconium titanate materials substituted with rare earth ions.