Preparation and structural study of Mg 12x Zn x TiO 3 ceramics and their dielectric properties from 1 Hz to 7.7 GHz Frida U. Ermawati 1,2 • Suminar Pratapa 1 • S. Suasmoro 1 • Thomas Hu ¨ bert 3 • Ulrich Banach 3 Received: 11 December 2015 / Accepted: 29 February 2016 Ó Springer Science+Business Media New York 2016 Abstract A series of Mg 1-x Zn x TiO 3 , x = 0–0.5 (MZT0– MZT0.5) ceramics was synthesised and characterised. The dielectric properties of the samples in the frequency range of 1 Hz–7.7 GHz were explored using three different methods: a contacting electrode method, a parallel-plate method and a perturbed resonator method. The electrical properties in the space charge and dipolar polarisation frequency ranges are discussed in relation to the phase composition and microstructure data. Differences in the zinc substitution divided the dielectrics into two groups, namely MZT0– MZT0.2 and MZT0.3–MZT0.5, each with different amount of a main Mg 1-x Zn x TiO 3 solid solution phase and a sec- ondary solid solution phase. Zinc substitution promoted the density of the ceramics, improved the purity of the main phase and increased the permittivity for frequencies up to 10 8 Hz, but reduced the permittivity in the microwave range. In the MZT0.3–MZT0.5 samples, for frequencies less than 1 MHz the quality (Q 9 f) factors were lower and log r a.c , the AC conductivity, was higher than for the MZT0–MZT0.2 samples. Above 10 MHz, the (Q 9 f) factors and log r a.c of the two groups were similar. 1 Introduction Magnesium titanate (MgTiO 3 ) has been the topic of intense investigation in the last two decades because of its potential applications in industrial ceramics [1–6]. MgTiO 3 -based ceramics could also be used as microwave dielectric res- onators, including microwave oscillators and in wireless technologies, because they exhibit a moderate dielectric constant, low dielectric loss (i.e., a high quality factor) and have good temperature stability. These properties have motivated researchers to investigate methods to fabricate MgTiO 3 -based ceramics with improved performance, including varying powder preparation techniques [2, 5–12], improving sintering behaviour [13], and controlling microstructures [14, 15]. Use of oxide additive agents to lower the sintering temperature and to alter the dielectric properties of MgTiO 3 -based ceramics has also been pro- posed [16–24]. New dielectric ceramics that use two or more materials with characteristic compensation to obtain a near-zero temperature coefficient of the resonance fre- quency have also been developed [25, 26]. The characteristics of the MgTiO 3 -based ceramics in the frequency range below microwave frequencies and how polarisation mechanisms in that frequency range affect the dielectric properties in the system have not been reported. The presence of additional phases of solid solutions in MgTiO 3 -based ceramics and how these phases affect the dielectric properties of the systems in the aforementioned frequency ranges also have not been investigated. Electronic supplementary material The online version of this article (doi:10.1007/s10854-016-4610-6) contains supplementary material, which is available to authorized users. & Frida U. Ermawati frida.ermawati11@mhs.physics.its.ac.id; frida.ermawati@unesa.ac.id S. Suasmoro suasm@its.ac.id 1 Physics Department, Faculty of Mathematics and Sciences, Institut Teknologi Sepuluh Nopember (ITS), Surabaya 60111, Indonesia 2 Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Negeri Surabaya (UNESA), Surabaya 60231, Indonesia 3 Bundesanstalt fu ¨r Materialforschung und –pru ¨fung (BAM), Unter den Eichen 44-46, 12203 Berlin, Germany 123 J Mater Sci: Mater Electron DOI 10.1007/s10854-016-4610-6