This study focuses on the preparation of $\mathrm{L}\mathrm{a}\mathrm{X}{\mathrm{O}}_3(\mathrm{X}=\mathrm{F}\mathrm{e},\mathrm{M}\mathrm{n},\mathrm{C}\mathrm{r},\mathrm{N}\mathrm{i})$ perovskite thin films using a simple set-up spin coating technique and the evaluation of their properties for application in switching memory devices. The properties of as-deposited films were thoroughly characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV-Vis spectroscopy, and a vibrating sample magnetometer (VSM). The results obtained revealed that the as-deposited films have a polycrystalline cubic structure. The film surfaces were uniform and densely packed without any voids, cracks, or pinholes. In addition, irregularly shaped grains were observed having an average size of $140$, $120$, $89$, and $70 \mathrm{n}\mathrm{m}$ for $\mathrm{L}\mathrm{a}\mathrm{F}\mathrm{e}{\mathrm{O}}_3$, $\mathrm{L}\mathrm{a}\mathrm{M}\mathrm{n}{\mathrm{O}}_3$, $\mathrm{L}\mathrm{a}\mathrm{C}\mathrm{r}{\mathrm{O}}_3$, and $\mathrm{L}\mathrm{a}\mathrm{N}\mathrm{i}{\mathrm{O}}_3$ films, respectively. VSM analysis demonstrated that $\mathrm{L}\mathrm{a}\mathrm{F}\mathrm{e}{\mathrm{O}}_3$ film exhibited superior magnetic properties compared to the other films. Furthermore, memory devices with $\mathrm{A}\mathrm{u}/\mathrm{L}\mathrm{a}\mathrm{X}{\mathrm{O}}_3(\mathrm{X}=\mathrm{F}\mathrm{e},\mathrm{M}\mathrm{n},\mathrm{C}\mathrm{r},\mathrm{N}\mathrm{i})/\mathrm{F}\mathrm{T}\mathrm{O}$ structures were fabricated, and their I-V characteristics were measured. In order to assess their performance, an endurance test was conducted. The findings indicated that $\mathrm{A}\mathrm{u}/\mathrm{L}\mathrm{a}\mathrm{F}\mathrm{e}{\mathrm{O}}_3/\mathrm{F}\mathrm{T}\mathrm{O}$ device exhibited higher $\raisebox{1ex}{$R_{HRS}$}\!\left/ \!\raisebox{-1ex}{$R_{LRS}$}\right.$ ratio ($~{7\times 10}^5$), low Set/Reset voltages, lower power consumption ($2.7\times {10}^{-4} \mathrm{W}$), and stable endurance with no significant degradation was observed in the LRS and HRS after 20 sweep cycles. These favorable parameters can be attributed to the reduced thickness, larger grain size, and excellent magnetic properties of the active-layer $\mathrm{L}\mathrm{a}\mathrm{F}\mathrm{e}{\mathrm{O}}_3$. Moreover, the conduction mechanism of the fabricated devices was investigated, revealing that the conduction in the LRS is primarily dominated by Ohmic behavior, while the HRS exhibited different conduction mechanisms.

The processing of bulk metals through the application of severe plastic deformation provides the opportunity for introducing significant grain refinement into bulk solids. In the present investigation, an aluminum alloy (Al-6061) was processed by high-pressure torsion (HPT) at room temperature under an applied pressure of 6.0 GPa up to a total of 5 turns. Detailed measurements after processing revealed the occurrence of continuous grain refinement and material strengthening with increasing imposed strain. The average grain size of the alloy was reduced from ~150 m to a grain size in the range of ~500 nm through processing by HPT. Although there was a difference in the average grain size of samples processed to different levels of imposed strain, careful inspection showed that the structures became similar after annealing at 250°C for 5 min. This suggests that the additional grain refinement introduced at large amounts of deformations is less stable at high temperatures. The results of this investigation, including the distributions of the grain sizes after annealing, are consistent with the predictions of a model based on the occurrence of continuous recrystallization in aluminum alloys having fine grain structures, large fractions of high-angle grain boundaries and where there is a large amount of deformation.