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Nanostructured MgO powders have been synthesized using chemical methods. Ammonium oxalate and Magnesium sulphate were used as the precursor materials. The weight ratios of the raw materials (ammonium oxalate/Magnesium sulphate) were 0.9, 1, 1.1, 1.2, 1.3, and 1.4. As a result of chemical reaction (between them), Magnesium oxalate was synthesized. Produced samples were analyzed by XRD and SEM. The results show that the best ratio (for ammonium oxalate/Magnesium sulphate) is 1.4. Produced Magnesium oxalate powder was heated at 450 and 550°C. The final product was MgO nanopowder. XRD studies indicate that the highest ratio of MgO was observed in the specimen heated at 450°C.

First principles and quasi-harmonic Debye model have been used to study the thermodynamic properties, enthalpies, electronic and optical properties of MgO up to the core–mantle boundary (CMB) condition (137 GPa and 3700 K). Thermodynamic properties calculation includes thermal expansion coefficient and capacity, which have been studied up to the CMB pressure (137 GPa) and temperature (3700 K) by the Debye model with generalized gradient approximation (GGA) and local-density approximation (LDA). First principles with hybrid functional method (PBE0) has been used to calculate the electronic and optical properties under pressure up to 137 GPa and 0 K. Our results show the Debye model with LDA and first principles with PBE0 can provide accurate thermodynamic properties, enthalpies, electronic and optical properties. Calculated enthalpies show that MgO keep NaCl (B1) structure up to 137 GPa. And MgO is a direct bandgap insulator with a 7.23 eV calculated bandgap. The bandgap increased with increasing pressure, which will induce a blue shift of optical properties. We also calculated the density of states (DOS) and discussed the relation between DOS and band, optical properties. Equations were used to fit the relations between pressure and bandgaps, absorption coefficient ($\alpha$($\omega$)) of MgO. The equations can be used to evaluate pressure after careful calibration. Our calculations can not only be used to identify some geological processes, but also offer a reference to the applications of MgO in the future.

We have determined the melting slopes as a function of pressure for MgO up to a pressure of 135 GPa, and for LiF up to a pressure of 100 GPa using the Lindemann law. Values of melting temperature have also been calculated from the melting slopes using Euler’s finite difference calculus method. It is found that the melting slope decreases continuously with the increase in pressure giving a nonlinear pressure dependence of the melting temperature. Values of bulk modulus and the Grüneisen parameter appearing in the Lindemann law of melting have been determined using the Stacey reciprocal K-primed equation of state and the Shanker reciprocal gamma relationship. The results for melting temperatures of MgO and LiF at different pressures are compared with the available experimental data. Values of melting temperatures at different pressures determined from the Al’tshuler relationship for the volume dependence of the Grüneisen parameter have also been included in the comparison presented.

The main component of magnetically selected cesium frequency standard is electron multiplier. Its working principle is to magnify cesium beam signal by emitting secondary electron through surface of material. Magnesium oxide (MgO) has been adopted due to its excellent capability to emit secondary electron. There are many ways to prepare MgO thin film, including evaporation, pulsed laser deposition and MOCVD. It has been studied that doping can be used to enhance its emission capability and decrease its working potential of the thin film. In this paper, Ti-doped MgO thin films were deposited by magnetron sputtering method. Titanium metal and MgO ceramic were co-sputtered in oxygen containing argon ambient with DC and RF power source, respectively. XRD results show that the deposited film has the texture of (100) and (110) orientation. The ratio of Ti/Mg were consistent in XPS and EDS. SEM and AFM show that the film is polycrystalline. Electron multiplier device was assembled, and the secondary electron emission coefficient of the Ti-doped MgO film is greater than that of the undoped one, especially 36% higher at low primary electron energy of 200 eV which is meaningful to cesium atomic frequency standard.

To enhance the fracture toughness of brittle lead titanate zirconate (PZT) ceramics, PZT nanocomposites with 0.1, 0.5 and 1.0 vol% MgO were fabricated by means of a conventional industrial fabrication method. Through scanning electron microscopy (SEM) observation, indentation tests and D–E hysteresis measurement, the properties of PZT/MgO nanocomposites are characterized. With the increase of additional MgO, the fracture mode of PZT/MgO nanocomposites gradually changes from intergranular to transgranular fracture and the fracture toughness is fairly enhanced. The electric coercive fields of PZT/MgO nanocomposites decrease gradually while the piezoelectric constant d₃₃ hardly changes except that of PZT-1.0 vol% MgO which decreases about 13% compared with the monolithic PZT.

The interaction between the H₂ molecule and the PdAg, PdAu, PtAg and PtAu bimetallic dimers deposited on the MgO(100) surface is investigated using density functional theory (DFT). The bimetallic dimers, whose molecular axes are considered to be perpendicular to the support surface, are adsorbed on top of an oxygen atom. Within this adsorption mode, the dimers prefer the orientation in which their Pd or Pt end is closer to the oxygen atom. The Ag and Au ends of the MgO-supported dimers capture the H₂ molecule with small exoenergetic effects. The spontaneous dissociation of H₂ on these ends does not occur. Thus, the MgO support decreases the ability of the dimers to adsorb and dissociate the H₂ molecule. From a catalytic viewpoint, it means that the activity of small bimetallic clusters toward the dissociative adsorption of H₂ is reduced when they are arranged on MgO. On the other hand, the results of our calculations show that the presence of the MgO support strengthens the binding of H atoms inside the PdAu, PtAg and PtAu dimers.

The effect of MgO on structure and dielectric properties of aluminoborosilicate glasses was investigated. FTIR data indicated that glass network was mainly built by tetrahedral [SiO₄], [BO₄], [AlO₄] and trigonal [BO₃]. A small amount of AlO₅ or AlO₆ units also existed. The glass system was characterized with lower dielectric constant (4.17 ~ 4.6) and dielectric loss (12.3 × 10^-4 ~ 14.77 × 10^-4) at 1 MHz. With the increase of MgO content, the quantity of AlO₅ or AlO₆ units decreased. The variation of density showed a decreasing tendency. The dielectric constant and loss were all found to decrease.

Low-temperature co-fired ceramics (LTCC) applied in millimeter/microwave and terahertz frequencies (5G/6G) have attracted a lot of attention recently. In this study, MgO-based dielectric ceramics were successfully sintered at 950°C with the sintering aids: x wt.% of LiF fluoride ($x=2$, 4, 6, 8, 10) and 0.5wt.% of BBSZ (Bi₂O₃–B₂O₃–SiO₂–ZnO) glass. BBSZ glass was introduced as another sintering aid to facilitate the sintering and densification. Crystalline structure and micro-morphology were investigated and analyzed. Dielectric properties (${\epsilon }_r$, $Q\times f$, ${\tau }_f$) at millimeter/microwave and terahertz wave frequencies were also studied. The ionic characteristics of Mg–O bond ($f_i$), the lattice energy (U) and the bond energy (E) were calculated and analyzed. It is suggested that the optimal $x=4$, where ${\epsilon }_r=10.5$, $Q\times f=120,000$GHz (@12GHz) and ${\tau }_f=-26$ppm/°C at millimeter/microwave range. When the frequency was up to terahertz (1.0THz), the ${\epsilon }_r$ values were 8.8–9.35 and the tan$\delta$ were $5.6\times 10^{-3}$–$8.7\times 10^{-3}$. The experimental results indicated that the low-temperature sintered MgO-based ceramics have potential for millimeter/microwave and terahertz communication applications.

We review recent developments in magnetic tunnel junctions with perpendicular easy axis (p-MTJs) for nonvolatile very large scale integrated circuits (VLSIs). So far, a number of material systems such as rare-earth/transition metal alloys, L1₀-ordered (Co, Fe)–Pt alloys, Co/(Pd, Pt) multilayers, and ferromagnetic-alloy/oxide stacks have been proposed as electrodes in p-MTJs. Among them, p-MTJs with single or double ferromagnetic-alloy/oxide stacks, particularly CoFeB–MgO, were shown to have high potential to satisfy major requirements for integration.