Hydrogen storage has become a challenge for researchers of this era because it is a cheap, clean, and non-pollutant element existing in nature. The current study has been performed in order to calculate the structural, electronic, optical, and magnetic properties of perovskite hydrides XGaH₃ (X = Rb, Cs, Fr) through the Cambridge serial total energy package code based on density functional theory. The comprehensive investigations have been made while utilizing three cations (Rb, Cs, and Fr) in the cubic form of the ABH₃ symmetry phase. The electronic properties of the considered hydrides have been investigated to determine bandgap, total density of states, and partial density of states, and their trends are devised against frequency (eV) of incident radiations. XGaH₃ hydrides have shown metallic behavior because no energy bandgap is noticed near the Fermi level. The lattice constants of RbGaH₃, CsGaH₃, and FrGaH₃ by utilizing the Perdew–Burke–Ernzerhof-Generalized Gradient Approximation (PBE + GGA) functional are found to be 4.0754 Å, 4.2137 Å, and 3.1237 Å. The local density approximation functional has also been used for calculations of lattice parameters, which are observed to be 3.9287 Å, 4.0673 Å, and 3.9818 Å, respectively. Anti-ferromagnetism is observed through magnetic analysis of the studied hydrides XGaH₃ (X = Rb, Cs, Fr). Regarding the optical analysis, FrGaH₃ is found to be a more suitable material for hydrogen storage. These novel materials exhibit minimum energy loss with maximum conductivity. The gravimetric ratio for hydrogen storage capacity is determined to be 2.5 wt. %, 2.0 wt. %, and 2.1 wt. % for RbGaH₃, CsGaH₃, and FrGaH₃, respectively. The present computational calculations of these hydrides are attempted for the first time, which may provide exceptional improvements for applications in hydrogen storage.

The mechanism of forming-free bipolar resistive switching in a Zr/CeO _x /Pt device was investigated. High-resolution transmission electron microscopy and energy-dispersive spectroscopy analysis indicated the formation of a ZrO _y layer at the Zr/CeO _x interface. X-ray diffraction studies of CeO _x films revealed that they consist of nano-polycrystals embedded in a disordered lattice. The observed resistive switching was suggested to be linked with the formation and rupture of conductive filaments constituted by oxygen vacancies in the CeO _x film and in the nonstoichiometric ZrO _y interfacial layer. X-ray photoelectron spectroscopy study confirmed the presence of oxygen vacancies in both of the said regions. In the low-resistance ON state, the electrical conduction was found to be of ohmic nature, while the high-resistance OFF state was governed by trap-controlled space charge-limited mechanism. The stable resistive switching behavior and long retention times with an acceptable resistance ratio enable the device for its application in future nonvolatile resistive random access memory (RRAM).

Resistance switching characteristics of CeO₂/Ti/CeO₂ tri-layered films sandwiched between Pt bottom electrode and two different top electrodes (Ti and TaN) with different work functions have been investigated. RRAM memory cells composed of TaN/CeO₂/Ti/CeO₂/Pt reveal better resistive switching performance instead of Ti/CeO₂/Ti/CeO₂/Pt memory stacks. As compared to the Ti/CeO₂ interface, much better ability of TaN/CeO₂ interface to store and exchange plays a key role in the RS performance improvement, including lower forming/SET voltages, large memory window (~10²) and no significant data degradation during endurance test of >10⁴ switching cycles. The formation of TaON thinner interfacial layer between TaN TE and CeO₂ film is found to be accountable for improved resistance switching behavior. Partial charge density of states is analyzed using density functional theory. It is found that the conductive filaments formed in CeO₂ based devices is assisted by interstitial Ti dopant. Better stability and reproducibility in cycle-to-cycle (C2C) resistance distribution and V_set/V_reset uniformity were achieved due to the modulation of current conduction mechanism from Ohmic in low field region to Schottky emission in high field region.