Ultra-low temperature epitaxial growth of lithium ferrite thin films by high-pressure sputtering

LiFe₅O₈ epitaxial thin films with high crystalline quality have been successfully synthesized on (001) MgAl₂O₄ substrates even at an ultra-low working temperature of 200 °C by using a high-pressure radio-frequency sputtering system. Better crystalline qualities of the epitaxial LiFe₅O₈ films can be obtained with an increase of the deposition temperature in the range from 200 °C to 800 °C. Moreover, the growth temperature can significantly affect the magnetic properties of the LiFe₅O₈ thin films. The strain states, crystalline quality and defect density should be the main causes for the tunable magnetic properties. Overall, the wide-temperature range processing window, especially the low deposition temperature of 200 °C, of the LiFe₅O₈ films by this method will offer flexibilities for direct integration with semiconductors, organic electronics, flexible electronic materials and other related elements which are sensitive to the processing temperature.