Flux-Mediated Doping of Bi into (La,Sr)MnO3 Films Grown on NdGdO3 (110) Substrates
Flux-Mediated Doping of Bi into (La,Sr)MnO3 Films Grown on NdGdO3 (110) Substrates
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DOI：
10.1021/acsaelm.0c00718
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发表时间：
2020-11-24
影响因子：
4.7
通讯作者：
Matsumoto，Yuji
中科院分区：
文献类型：
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作者：
Mizufune，Koji;Naganuma，Hiroshi;Matsumoto，Yuji
采用助熔剂掺杂法在NaGdO 3（NGO）衬底上生长了Bi掺杂（La，Sr）MnO 3 [（Bi0.18La0.56Sr0.30）Mn0.96O3：BLSMO，tBLSMO= 63 nm]外延薄膜。即，虽然Bi是高挥发性元素，但在Bi基液体助熔剂共存下的（La，Sr）MnO 3（LSMO）膜的生长导致成功地将Bi掺杂到LSMO膜中。成分分析表明，Sr优先存在于膜中，Sr的分配平衡系数（K）大于Mn和La，这是Bi取代La位的证据之一。由于NGO衬底的压缩应变，所获得的BLSMO薄膜具有四方畸变结构，并且四方性和结晶度随着Bi的量的增加而增强。BLSMO薄膜的四方畸变导致垂直磁各向异性。从膜体到膜表面，La位的Bi取代和Mn ~（2+）/Mn ~（3+）的比值均增加，磁矩降低到0.6 μB/Mn。虽然BLSMO薄膜的磁矩很低，但其居里温度高于室温，磁熵变也很小，|ΔSM|的2.4 mJ/（cm 3·K）。BLSMO薄膜有利于磁热效应的应用，以及自旋转移力矩器件，如微波振荡器。
Bi-doped (La,Sr)MnO3[(Bi0.18La0.56Sr0.30) Mn0.96O3: BLSMO,tBLSMO= 63 nm] epitaxial films were grown on NaGdO3(NGO) substrates by a flux-mediated doping approach. That is, the growth of a (La,Sr)MnO3(LSMO) film under the coexistence of a Bi-based liquid flux leads to successful Bi doping into the LSMO film, though Bi is a highly volatile element. The composition analysis revealed that Sr preferentially existed in the film over the flux and that Sr has a larger distribution equilibrium coefficient (K) than those of Mn and La, which is one of the evidence that Bi has substituted for the La site. The obtained BLSMO films had a tetragonal distorted structure owing to a compressive strain from the NGO substrate, and the tetragonality and the crystallinity were enhanced by increasing the amount of Bi. The tetragonal distortion of the BLSMO films induced a perpendicular magnetic anisotropy. Both the Bi substitution at the La site and the ratio of Mn2+/Mn3+increased from the film body to the surface, a magnetic moment was decreased to 0.6 μB/Mn. Although the magnetic moment was low, the Curie temperature of the BLSMO film was above room temperature (RT), and the magnetic entropy change |ΔSM| of 2.4 mJ/(cm3·K) was observed near RT. The BLSMO film is favored for magnetocaloric effect applications as well as spin-transfer-torque devices such as microwave oscillators.