The absence of exchange bias with (001)‐oriented tetragonal‐like BiFeO3 films
The absence of exchange bias with (001)‐oriented tetragonal‐like BiFeO3 films
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DOI：
10.1002/pssb.201350079
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发表时间：
2014-04
期刊：
影响因子：
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通讯作者：
Qingyu Xu;Xueyong Yuan;X. Xue;Zhong Shi;Zheng Wen;J. Du
中科院分区：
文献类型：
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作者：
Qingyu Xu;Xueyong Yuan;X. Xue;Zhong Shi;Zheng Wen;J. Du
使用 NdAlO3 (NAO) 作为缓冲层，在 (001) LaAlO3 基底上成功制备了厚度高达 480 nm 的单相类四方 BiFeO3 (T-BFO) 薄膜。单斜晶畸变随着 T-BFO 薄膜厚度的增加而增加。在 T-BFO/NiFe 双层中观察到可忽略不计的小交换偏置场 (HE) (<8 Oe)。在NAO和BFO之间插入2nm厚的La0.67Sr0.33MnO3（LSMO）薄膜可以保持单相T-BFO的结构。在低于 100 K 的 LSMO/T-BFO 双层中观察到 HE 和矫顽力强烈增强，这归因于 NAO 缓冲层施加的压缩应变导致超薄 LSMO 层中反铁磁和铁磁相的相分离和共存。我们的结果清楚地表明，T-BFO 无法在相邻铁磁层上提供有效的交换偏置场，并提供了可能的解释。
Single‐phase tetragonal‐like BiFeO3 (T‐BFO) films with thickness up to 480 nm have been successfully prepared on (001) LaAlO3 substrates using NdAlO3 (NAO) as a buffer layer. The monoclinic distortion increases on increasing the thickness of T‐BFO films. Negligible small exchange bias field (HE) (<8 Oe) has been observed in T‐BFO/NiFe bilayers. The insertion of a 2‐nm thick La0.67Sr0.33MnO3 (LSMO) film between NAO and BFO can keep the structure of single‐phase T‐BFO. Strongly enhanced HE and coercivity has been observed below 100 K in LSMO/T‐BFO bilayer, which has been attributed to the phase separation and coexistence of antiferromagnetic and ferromagnetic phases in the ultrathin LSMO layer due to the compressive strain exerted by the NAO buffer layer. Our results clearly demonstrate that T‐BFO cannot provide an effective exchange bias field on the adjacent ferromagnetic layer, and the possible explanation has been provided.