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Spinel lithium ferrite (LiFe5O8) has attracted a great deal of attention due to its potential applications in isolators, circulators, and phase shifters. In this work, thin films of LiFe5O8 were fabricated on (001) MgO substrates using pulsed laser deposition technology. Thin films with excellent crystallization qualities were acquired by controlling the growth temperature. Interestingly, the results from reciprocal space mappings (RSMs) indicate that the in-plane lattice parameter a and the out-of-plane lattice parameter c were modulated by changing the film growth temperature. Moreover, the magnetism of LiFe5O8 thin films with different temperatures was significantly studied by vibrating sample magnetometer (VSM) and ferromagnetic resonance (FMR) measurements. These findings illustrate that controlling the growth temperature of the films is an effective method to tailor the lattice parameter and to further modify the magnetic properties of epitaxial LiFe5O8 thin films.

Nanocrystalline Li0.5Fe2.1Cr0.4O4 ferrites were prepared by using the polyethylene glycol (PEG) gel method. Their structure, morphology and magnetic properties were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), VSM and Mossbauer spectroscopy. The saturation magnetization decreases with decreasing particle size. The decrease in magnetization results from nonmagnetic layer, existing at the surface of the ferrite particles, the thickness of which is 1.1 nm. As the particle size becomes smaller, a superparamagnetic behaviour appears.

First-principles calculations using density-functional theory were carried out to optimize the B19′ phase crystal structure (space group P21/m) in NiTi alloy by relaxing the Hellmann–Feynman forces. A more stable base centered orthorhombic structure (space group Cmcm) was obtained after the tension had been released. This base centered orthorhombic structure could be regarded as two martensite unit cells twined by the (001) plane with a twin width of 0.9228 nm. Based on this finding, the discrepancy between the geometric theory prediction that the atomic-scale (001) plane twinning cannot exist and experimental observation that the atomic-scale (001) plane twinning does appear in the B2–B19′ martensite transformation could be explained.