Improvement of anti-fatigued strain in KTN-based single crystals with regular periodic hierarchical domain structure

Ion doping can significantly affect the microdomain structures and the properties of ferroelectric materials, such as strain and piezoelectric properties. Here, we report a remarkable improvement in the antihysteretic and antifatigue strain properties via Mn and Fe codoping in KTN single crystals. By comparison among pure KTN, Mn-doped KTN, and (Mn, Fe) codoped KTN, the results reveal that Mn and Fe doping can significantly enhance antifatigue properties and reduce the domain switching fields, exhibiting large strain (0.17%) under a low driven field (5 kV cm−1), giant d33* ∼ 3160 pC N−1, low strain hysteresis (Hys < 20%), and antifatigue (just about 6% drop after 105 cycles). In addition, the microdomain structures' images reveal that Mn and Fe codoping can not only affect the domain structure and size but also induce the formation of a regular periodic hierarchical domain structure. Therefore, Mn&Fe:KTN is expected to be one of the most potential ferroelectric materials, which is meaningful for the further study of antifatigue in KTN-based ferroelectric materials.