Dielectric studies of Co3−xMnxO4 (x=0.1–1.0) cubic spinel multiferroic

Abstract

A series of Co3−xMnxO4 (x=0.1–1.0) multiferroic cubic spinel ceramics were prepared to study the effect of Mn substitution at Co site on the crystal structures and dielectric properties. No significant change in the structural symmetry was observed with increasing x up to 1.0. A linear increase in lattice parameter with x is attributed to the substitution of Co3+ by Mn3+ (large ionic radii) at the octahedral sites. An antiferromagnetic-type ordering of Co3O4 changes to ferrimagnetic-type order after incorporation of Mn. The effect of Mn substitution on the dielectric constant and loss tangent was studied over a wide range of frequency (75 kHz–5 MHz) and temperature of 150–450 K. The measured value of room temperature ac conductivity at 1.0 MHz was found to increase from 2.0×10−6 to 4.4×10−4 Ω−1 cm−1 and follows power law (σac=Aωs) behavior. The dielectric constant ε′(ω) shows a weak frequency dispersion and small temperature dependence below 250 K for all ceramic samples. However, a strong temperature and frequency dependence on ε′(ω) was observed at higher temperature (>250 K). The temperature dependent ε′(ω) data show the existence of room temperature ferroelectricity in all prepared samples.

Conduction mechanism in cobalt rich Co3-xMnxO4 (0.1 ≤ x ≤ 1.0) spinel oxide ceramics

“…1 (c). The detailed analysis of the XRD data is given elsewhere [9,12]. FTIR spectra of CMO (0.1  x 1.0) ceramics are shown in inset of Fig.…”

“…The detailed of mixing, calcination, sintering and preparation of cylindrical discs was explained in reported literature [9,12]. Room temperature powder X-ray diffraction patterns and Fourier transform infrared spectra were recorded using a Bruker AXS X-ray diffractometer and Perkin Elmer RX-1 FTIR spectrometer, respectively.…”

“…For device point of view, electronic properties of solids are tremendously important for applications in storage of data, microelectronics, communication technologies and other related fields. An earlier report on singlephase Co3-xMnxO4 ceramics shows their negative temperature coefficient [8], multiferroic [9] and universal dielectric [10] nature. In the literature a number of studies have been devoted to manganese rich phases of Co3-xMnxO4 (x ≥ 1.5), and very few studies have been focused towards the cobalt rich phases with x ≤ 1.0.…”

Structural and electrical properties of Mn1.56Co0.96Ni0.48O4 NTC thermistor films

“…The electrical conduction of this kind of NTC material is accomplished by the small-polaron hopping between localized Mn 3+ and Mn 4+ states under the assistance of thermal activation [15,16]. The influences of composition and annealing temperature on film crystallization and properties have been studied [17][18][19][20]. In this paper, the structural and electrical properties of the MCN NTC thermistor films were investigated.…”

The effects of size and orientation on magnetic properties and exchange bias in Co3O4 mesoporous nanowires

“…5,6 Doped Co 3 O 4 is also of interest as a multiferroic material 7 and as a parent compound for other layer-structured cobalt oxides, e.g. Na x CoO 2 in the thermopower field 8 and as a superconductor.…”