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Zirconolite, a potential candidate for the immobilization of actinides was investigated for the induced effects of α-particles simulated through ion beam irradiation. Nd-doped zirconolite pellets (Ca0.8Nd0.2ZrTi1.8Al0.2O7) synthesized through two step solid state sintering were irradiated with 30 keV He+ ions and analyzed for irradiation induced structural modulations through glancing angle X-ray diffraction technique. Diffraction patterns showed reduction in peak intensity and broadening of peaks with increasing fluence, indicating loss of crystallinity. Though zirconolite didn’t amorphize even upon irradiation at the maximum fluence used i.e. 1 × 1017 ions/cm2. Measured lattice strain enhanced with fluence, further suggesting distortion of the structure.

Synroc minerals have been studied since decades for immobilization of high-level radioactive wastes released from nuclear weapons and nuclear reactors. Among them, the zirconolite, due to its high radiation and aqueous resistance and high waste loading, is considered as a potential candidate for containment purposes. Though irradiation damage effects of swift heavy ions in the material remain a major concern of study, a single phase Nd-doped zirconolite samples prepared through conventional solid-state reaction were irradiated with 120 MeV Au+ ions to study radiation damage effects. Irradiation-induced effects were investigated using ex-situ XRD and micro-Raman spectroscopic techniques. Zirconolite has been observed to undergo amorphization which is confirmed through disappearance of characteristic x-ray diffraction peaks and appearance of broad diffuse scattering bands. Amorphization trend with fluence appeared linear at lower fluences followed by saturation at higher fluences inferring therewith the formation of ion tracks. The ion fluence dependent Raman examination was also found to be in line with the XRD observations. However, the presence of Raman modes, characteristic of zirconolite in the 100–1000 cm−1 region, showed intact behavior of the local structure. To sum up, the 120 MeV heavy Au+ ions developed columnar defects, vacancies and induced micro-strains that lead to the bonds distortion and eventually amorphization of the zirconolite though retaining local ordering.

Zirconolite, a potential matrix for the immobilization has been studied to investigate the doping behaviour of Ce in its structure to design a nuclear waste form that can accommodate both trivalent and tetravalent nuclear wastes. So, samples have been prepared as per the composition Ca0.8Ce0.2ZrTi1.8Al0.2O7 using solid-state method and analysed for their structural, micro-structural and chemical properties. A dense-packed structure was found in SEM with the phase of zirconolite-2M as confirmed by XRD and Raman techniques. Quantitative analysis of XPS inferred that the percentage of Ce(III) in the sample was about ~ 75% indicating the reduction of Ce at higher temperatures.

In the study of nuclear materials, zirconolite ceramic doped with yttrium, as a surrogate for minor actinides, is chosen to study the effects of doping on structural and electronic response which are crucial parameters in the determination of the stability and durability of materials under radiation effects. The samples Ca0.9Zr0.9Y0.2Ti2O7 have been synthesized using conventional solid-state route of two-step sintering process. X-ray diffraction and Raman spectroscopy studies are performed on samples to examine the effect of temperatures on formation of phase. The scanning electron microscopy analysis revealed formation of porous micro-structure at 1200 °C while dense-packed morphology at sintering temperature of 1300 °C. Both XRD and Raman spectroscopy on samples sintered at 1300 °C reveal almost single phase (2 M zirconolite) formation with 20% molar concentration of yttrium thus indicating high loading capacity of zirconolite. The formation of 2M-zirconolite phase is also confirmed from Rietveld refinement of the spectra. Analysis of refinement of spectra of sample sintered at 1300 °C indicates substitution of Y3+ ions against both Ca and Zr sites with similar occupancy of ∼10%, while the altered chemical environment is found to affect the bond length. XPS confirms the presence of Y3+ in the structure and illustrates further that oxidation states of all the elements remain unaltered. Finally, the measurements and analysis show that zirconolite can retain its structural integrity by incorporation of 20% molar concentration of yttrium on Ca and Zr sites and can be a promising waste form for burning the minor actinides in advance accelerators.

Over the past 60 years, the safe disposal of high-level wastes (HLWs) produced during reprocessing of spent nuclear fuel has become a serious issue and a world-wide challenge. The radionuclides contained in HLWs severely affect the biosphere due to their long half-life and high radiotoxicity. In order to meet this challenging task, the research is underway to develop an advanced stable nuclear waste form which will be capable to accommodate the radiation effects under repository conditions and over geological time scales. Among potential waste forms, zirconolite has been proven to be a good candidate for the desired purpose due to its high radiation and thermal stability and high loading capacity to accommodate the wastes of lanthanides and actinides without any effect on the crystallinity of zirconolite material. In this article, a detailed review has been carried out on ongoing developments in these materials to contain HLWs, various synthesis methods employed to practice these materials, preparation manners of single phase zirconolite compositions and subsequently the structural characterization of zirconolites doped with various tri- and/ or tetravalent lanthanides and actinides as also their loading capacities.

Magnetoelectric (ME) multiferroics are materials in which electric and magnetic dipoles are coupled. The possibility to control electrical properties in the material using magnetic field (and vice versa) in case of ME multiferroics make these materials highly versatile and useful. Over the years many magnetically induced ferroelectrics have been discovered but they show ME effect at low temperature and require high external magnetic field. Recently many Y-type hexaferrites (BaxSr(2-x)Me2Fe12O22), where Me is a divalent cation, have shown ME effect at room temperature and low applied magnetic field, that too in a single phase. Studies suggest that there are several factors that influence the ME properties of Y-type hexaferrites, such as annealing process, the sintering temperature, and ion substitution. It was reported that the lower critical magnetic field was required for inducing electrical polarization when Mg replaces Zn to form Ba2Mg2Fe12O22. Also, it was reported that Strontium doping at Barium site changes the magnetic transition temperature and enhances the ME effects. And it was found that increasing Co content favours high electrical resistivity. Further research and development require careful analysis and compilation of the work on hexaferrites. Y-Type hexaferrite is the focus of this review. Its structure, reason behind ME effect and salient research works has been discussed.

Effects of titanium substitution on electrical and magnetic properties of ceramics of barium ferrites having general formula BaTixFe12-xO19, with values of x as 0.00, 0.005, 0.01, 0.02 and 0.03 have been investigated. The compounds are synthesised using two step sintering solid-state rout and characterized by employing SEM and x-ray diffraction. All the titanium substituted compounds show hexagonal single phase symmetry. Gradual loss of saturation magnetization, significant increase in total polarization, rise in value of dielectric constant and upward trend in resistivity are the main parameters observed with titanium substitution on Fe ions. The Curie temperature shows declining trend with dopant concentration. The material is found to exhibit electrical behaviour at expense of its intrinsic magnetic characteristics paving way for Ti ion substitutions for controlled magnetic and electrical properties of barium ferrite.

The immobilization of minor actinides and alkaline-earth metal is a major concern in nuclear industry due to their long-term radioactive contribution to the high level waste (HLW). Materials having zirconolite, pyrochlore, and perovskite structure are promising candidates for immobilization of HLW. The zirconolite which exhibits high radiation stability and corrosion resistance behavior is investigated for its radiation stability against alpha particles in the present study. CaZrTi 2 O 7 pellets prepared using solid state reaction techniques, were irradiated with 30 keV He + ions for the ion fluence varying from 1 × 10 17 to 1 × 10 21 ions/m 2 . Scanning electron microscopy (SEM) images of the un-irradiated sample exhibited well separated grains with average size of about 6.8 μm. On the ion irradiation, value of the average grains size was about 7.1 μm, and change in the microstructure was insignificant. The X-ray photoelectron spectroscopy (XPS) studies showed a shift in the core level peak position (of Ca 2p, Ti 2p and Zr 3d) towards lower binding energy with respect to pristine sample as well as loss of oxygen was also observed for sample irradiated with the ion fluence of 1 × 10 20 ions/m 2 . These indicate a decrease in co-ordination number and the ionic character of M O bond. Moreover, core level XPS signal was not detected for sample irradiated with ion fluence of 1 × 10 21 ions/m 2 , suggesting surface damage of the sample at this ion fluence. However, X-ray diffraction (XRD) studies showed that zirconolite was not amorphized even on irradiation up to a fluence order of 1 × 10 21 ion/m 2 . But, significant decrease in peak intensity due to creation of defects and a marginal positive peak shift due to tensile strain induced by irradiation, were observed. Thus, XRD along with XPS investigation suggests that reduction, decrease in co-ordination number, and increase in covalency are responsible for the radiation damage in zirconolite.

Efforts have been made to ease process of producing widely used multilayered ceramics of Barium Zirconium Titanium Oxides and study their dielectric behaviour and structural properties. For this purpose, adequate proportions of Barium Carbonate, Zirconium Oxide and Titanium Oxide were taken and hand milled for 2 hours. Neodymium composition of the order of 0.1% and 0.2% was used for doping to weight percentage of BaZr0.2Ti0.8O3. The samples were authenticated using raw data obtained from Bruker AXS D8 advance Copper KL alpha source XRD equipment. Further, the samples were studied for their phase transition, composition, single phase perovskite structure using XRD technique. The technique has also been applied to know formation of stable homogeneous solid solution from XRD parameters. The other physical parameters like the morphology, micro structural information, crystal arrangements and topography have also been observed through SEM. The SEM has revealed information related to grain size development and composition of sample with fine agglomerates. For complete study of the compounds the atomic and weight composition has also been examined by Electron Dispersive Spectroscopy patterns. The comparison has been made with other works on ceramics at various frequencies and has yielded very interesting results.

The theoretical B(E2) ratios have been calculated on DF, DR and Krutov models. A simple method based on the work of Arima and Iachello is used to calculate the reduced transition probabilities within SU(3) limit of IBA-I framework. The reduced E2 transition probabilities from second excited states of rare-earths and actinide even–even nuclei calculated from experimental energies and intensities from recent data, have been found to compare better with those calculated on the Krutov model and the SU(3) limit of IBA than the DR and DF models.

The gamma-gamma sum peak method has been applied to the measurement of the total attenuation factors G22, in different concentrations of biological material, bovine serum albumin (BSA) using 133Ba as a probe. It is observed that G22 is inversely proportional to the correlation time of the two cascade radiations and to the concentration of biological sample surrounding the probe.

Relative K-capture probabilities to three levels of 1911r are determined from the decay of 191 Pt using the sum coincidence method based on summing of gamma rays and K X-rays in a single HPGe detector. The results agree with theoretical values. The electron-capture decay energy calculated using j3-decay properties to different levels belonging to the same rotational family is in agreement with the experimental value.

The low energy weak transitions in gamma band of 160 Dy have been investigated. Two new transitions namely 106.72 (4 γ + –3 γ + ) and 132.98 keV (4 γ + –2 γ + ) have been identified in addition to two already reported in this band. The E2 branching ratios have been calculated experimentally and are compared with IBA theory for intra as well as gamma to ground band transitions. E2/M1 mixing ratios calculated from Alaga rules as well as Greiner's theory are in good agreement.

KX ray-gamma ray coincidence and sum coincidence methods have been used to measure the relative K-capture probabilities to 810.46, 1085.89, 1233.87, 1529.81, 1579.43 and 1649.93 keV levels in 152 Sm from the decay of 152 Eu. Ten weak gamma transitions not reported earlier have been identified. B ( E 2) ratios for six out of these and for the transitions from the states of gamma band in 152 Sm compare favourably with the interacting boson model predictions.