锂尖晶石铁氧体薄膜,LiFe5O8因其有效激发的潜力而备受科学关注,由于其绝缘特性,自旋电流的操纵和传播,高饱和磁化强度,和居里温度,以及他们的超低阻尼值。此外,LiFe5O8是目前在开发基于磁性离子控制的自旋电子器件方面最有趣的材料之一,为此,控制锂的原子含量至关重要。在这项工作中,我们证明了双离子束溅射是一种合适的技术,可以通过使用生长过程中Ar和O2离子形成的辅助离子束的不同能量来定制锂铁氧体(LFO)薄膜的锂含量。没有援助,无序的岩盐LFO相(即,LiFeO2)可以确定为主要相。在光束辅助下,在(0001)Al2O3衬底上获得了高度平面外取向的(111)LFO薄膜,该薄膜以无序的尖晶石结构为主相,锂浓度高于和低于化学计量的尖晶石相,即,LiFe5O8。在1025K下对薄膜进行后退火之后,当锂浓度高于化学计量值时,发现高度有序的铁磁尖晶石LFO相。锂含量较低,反铁磁赤铁矿(α-Fe2O3)相出现并与铁磁LixFe6-xO8共存。这些结果开辟了控制锂铁氧体基薄膜的性能以使其能够用于先进的自旋电子器件的可能性。
Thin films of lithium spinel ferrite, LiFe5O8, have attracted much scientific attention because of their potential for efficient excitation, the manipulation and propagation of spin currents due to their insulating character, high-saturation magnetization, and Curie temperature, as well as their ultra-low damping value. In addition, LiFe5O8 is currently one of the most interesting materials in terms of developing spintronic devices based on the ionic control of magnetism, for which it is crucial to control the lithium\'s atomic content. In this work, we demonstrate that dual ion beam sputtering is a suitable technique to tailor the lithium content of thin films of lithium ferrite (LFO) by using the different energies of the assisting ion beam formed by Ar+ and O2+ ions during the growth process. Without assistance, a disordered rock-salt LFO phase (i.e., LiFeO2) can be identified as the principal phase. Under beam assistance, highly out-of-plane-oriented (111) thin LFO films have been obtained on (0001) Al2O3 substrates with a disordered spinel structure as the main phase and with lithium concentrations higher and lower than the stoichiometric spinel phase, i.e., LiFe5O8. After post-annealing of the films at 1025 K, a highly ordered ferromagnetic spinel LFO phase was found when the lithium concentration was higher than the stoichiometric value. With lower lithium contents, the antiferromagnetic hematite (α-Fe2O3) phase emerged and coexisted in films with the ferromagnetic LixFe6-xO8. These results open up the possibility of controlling the properties of thin lithium ferrite-based films to enable their use in advanced spintronic devices.