Magnetic Properties of Polycrystalline Bismuth Ferrite Thin Films Grown by Atomic Layer Deposition
Magnetic Properties of Polycrystalline Bismuth Ferrite Thin Films Grown by Atomic Layer Deposition
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DOI：
10.1021/jz502285f
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发表时间：
2014-12-18
影响因子：
5.7
通讯作者：
Leskela, Markku
中科院分区：
文献类型：
--
作者：
Jalkanen, Pasi;Tuboltsev, Vladimir;Leskela, Markku
采用原子层沉积（ALD）方法在Pt/SiO2/Si衬底上生长了BiFeO 3（BFO）多晶薄膜。50 nm厚的膜被发现表现出高电阻率，良好的形态完整性，和均匀性所应用的ALD技术实现。磁性表征表明，在300 ~ 2 K温度范围内，饱和磁化强度为25 emu/cm（3），磁化强度随温度变化范围为5 ~ 530 Oe。在薄膜中观察到的磁性被发现逐渐改变铁磁自旋顺序钉扎磁畴相互作用混合弱自旋玻璃样行为的磁阻挫反铁磁/铁磁（AFM-FM）自旋顺序取决于温度和施加的磁场的大小。反铁磁顺序的自旋摆线被打破在多晶薄膜的晶体尺寸小于摆线长度（类似于60 nm）。未补偿的旋摆线和磁畴壁被认为是BFO薄膜的高磁化强度的原因。
The atomic layer deposition (ALD) method was applied to grow thin polycrystalline BiFeO3 (BFO) films on Pt/SiO2/Si substrates. The 50 nm thick films were found to exhibit high resistivity, good morphological integrity, and homogeneity achieved by the applied ALD technique. Magnetic characterization revealed saturated magnetization of 25 emu/cm(3) with temperature-dependent coercivity varying from 5 to 530 Oe within the temperature range from 300 to 2 K. Magnetism observed in the films was found to change gradually from ferromagnetic spin ordering to pinned magnetic domain interactions mixed with weak spin-glass-like behavior of magnetically frustrated antiferromagnetic/ferromagnetic (AFM-FM) spin ordering depending on the temperature and magnitude of the applied magnetic field. Antiferromagnetic order of spin cycloids was broken in polycrystalline films by crystal sizes smaller than the cycloid length (similar to 60 nm). Uncompensated spincycloids and magnetic domain walls were found to be the cause of the high magnetization of the BFO films.