Temperature dependence of exchange biased multiferroic BiFeO3/Ni81Fe19 polycrystalline bilayer
Temperature dependence of exchange biased multiferroic BiFeO3/Ni81Fe19 polycrystalline bilayer
复制标题
DOI：
10.1088/1361-6463/aab023
复制
发表时间：
2018-03
期刊：
影响因子：
--
通讯作者：
J. Richy;T. Hauguel;J. Jay;S. Pogossian;B. Warot-Fonrose;C. Sheppard;J. Snyman;A. Strydom
中科院分区：
文献类型：
--
作者：
J. Richy;T. Hauguel;J. Jay;S. Pogossian;B. Warot-Fonrose;C. Sheppard;J. Snyman;A. Strydom
研究了不同 BiFeO3 厚度的多晶 BiFeO3/Ni81Fe19 双层中交换偏压特性的温度依赖性。使用场冷却协议，交换偏置双层中显示了交换偏置场的非单调行为。另一种与 BiFeO3 热激活能相关的热协议 Soeya 协议被执行，并揭示了交换偏置场的两步演化。这两种不同协议的结果与之前报道的外延 BiFeO3 测量结果相似，表明驱动机制独立于长程晶体排列（即外延或多晶）。 BiFeO3 的一个固有特性被认为是热相关磁化反转的驱动机制：BiFeO3 自旋的倾斜导致对交换耦合的双二次贡献。磁化反转角行为的温度依赖性与此处研究的交换偏置双层的双二次贡献的存在一致。
The temperature dependence of exchange bias properties are studied in polycrystalline BiFeO3/Ni81Fe19 bilayers, for different BiFeO3 thicknesses. Using a field cooling protocol, a non-monotonic behavior of the exchange bias field is shown in the exchange-biased bilayers. Another thermal protocol, the Soeya protocol, related to the BiFeO3 thermal activation energies was carried out and reveals a two-step evolution of the exchange bias field. The results of these two different protocols are similar to the ones obtained for measurements previously reported on epitaxial BiFeO3, indicating a driving mechanism independent of the long-range crystalline arrangement (i.e. epitaxial or polycrystalline). An intrinsic property of BiFeO3 is proposed as being the driving mechanism for the thermal dependent magnetization reversal: the canting of the BiFeO3 spins leading to a biquadratic contribution to the exchange coupling. The temperature dependence of the magnetization reversal angular behavior agrees with the presence of such a biquadratic contribution for exchange biased bilayers studied here.