磁性薄膜材料平面霍尔效应的研究

Planar Hall Effect (PHE) sensors have the advantages of smaller thermal drift, easier to get linear response, higher signal-to-noise ratio, lower cost, more simple preparation process etc. They are widely used in the information technology, electronic technique, magnetic read/write and automatic control fields. Compared to the current GMR and AMR sensors, PHE sensors have their unique advantages in biosensors. However, the low sensitivity and the weak magnetic stability of PHE sensors are serious problems for the practical application although the plenty of researches have been done. It's necessary to take appropriate measures to improve their sensitivities and magnetic stability. The science questions which will be resolved by this research are: (1) How to control the microstructure to improve the PHE sensitivity of thin films. (2)How to increase the magnetic stabilities of PHE effect thin films. What's the inner physical mechanism. To resolve these science questions, we put forward (1) The nanolayers（Al2O3 or MgO et al）and metal layers(Pt or Ir et al) are inserted beside the traditional ferromagnetic(FM) films to improve the sensitivities of films.(2) The antiferomagnetic(AFM) are deposited on the FM/nanolayers or metal layers and FM/inserting layers/AFM films are prepared to increase the magnetic stabilities by magnetostatic coupling. These researches will provide a basis for preparing the magnetic films with high sensitivity and magnetic stabilities.

平面霍尔效应（PHE）传感器具有低热漂移、线性度以及信噪比，且成本低，工艺简单，可以广泛应用在信息、电子、磁读写及自动控制等领域，尤其在生物传感器方向，比GMR和AMR更有优势。尽管做了大量的研究工作，但是PHE传感器进入实际应用还存在难题-灵敏度低且磁稳定性差。因此，必须采取适当的措施提高其灵敏度及磁稳定性。 本研究需要解决的科学性问题是： （1）如何控制微结构提高薄膜材料的PHE灵敏度？ （2）如何提高PHE薄膜的磁稳定性？其内在物理机制是什么？ 为了解决上述问题，我们提出（1）在传统的铁磁（FM）薄膜两边插入纳米氧化层（Al2O3、MgO等）和金属插层（Pt、Ir等），提高薄膜的PHE灵敏度。（2）在FM/纳米氧化层或金属插层结构的薄膜上沉积反铁磁层(AFM)，制备FM/插层/AFM多层膜，通过静磁耦合提高薄膜的磁稳定性。为制备具有高PHE灵敏度及磁稳定性的磁性薄膜材料打下基础。

平面霍尔效应（PHE）传感器具有低热漂移、线性度以及信噪比，且成本低，工艺简单，可以广泛应用在信息、电子、磁读写及自动控制等领域，尤其在生物传感器方向，比GMR和AMR更有优势。尽管做了大量的研究工作，但是PHE传感器进入实际应用还存在难题—灵敏度低且磁稳定性差。因此，必须采取适当的措施提高其灵敏度及磁稳定性。为了解决上述问题，我们（1）在传统的铁磁（FM）薄膜两边插入纳米氧化层和金属插层，提高薄膜的PHE灵敏度。（2）在FM/纳米氧化层或金属插层结构的薄膜上沉积反铁磁层(AFM)，制备FM/插层/AFM多层膜，通过静磁耦合提高薄膜的磁稳定性。在Ta/MgO(NiO)/NiFe/MgO(NiO)/Ta薄膜中，和Ta/NiFe/Ta相比PHE灵敏度提高了150%。在NiFe/Cu(Au)/IrMn薄膜中，通过静磁耦合提高了薄膜的磁稳定性。这些结果为制备具有高PHE灵敏度及磁稳定性的磁性薄膜材料打下基础。