為了要了解NiFe/Cr/NiFe薄膜其磁性與結構的關係，本實驗室利用分子束磊晶(Molecular Beam Epitaxy,MBE)系統來成長高品質的NiFe/Cr/NiFe薄膜。而成長方式是階梯式成長法方式來成長薄膜，利用只改變不同的成長厚度，但卻又可以固定其它成長條件，如成長溫度、基板種類等，因而來探討比較不同成份比例的因素。藉由改變不同的成長因素，來找出成長良好垂直磁異向性所需的條件。
磊晶時以臨場（in situ）電子繞射 （RHEED）確認上下兩層Py ( 111 ) 和中間層Cr( 110 ) 是否有良好的結構。對於Cr( 110 )層而言,由於對稱性以及Cr( 110 )Py ( 111)兩者晶格之不匹配，造成有兩個in-plane domains, 即 KS and NW domains。以LMOKE 及 中子散射分析Py/Cr/Py三層薄膜之磁性結構。結果顯示這個Py層之間的耦合效應取決於Cr層的厚度 (tCr)。當上下兩層Py厚度為5.0nm且tCr=2.5nm時，發現反鐵磁耦合效應為最明顯。

By molecular beam epitaxy (MBE), the author has prepared high-quality Ni80Fe20 / Cr / Ni80Fe20 trilayers with different spacer (Cr) thickness on Al2O3(11-20) substrates. This thesis study on the magnetoresistance effect and the oscillation behavior of antiferromagnetic coupling as a function of the Cr thickness in Ni80Fe20 / Cr / Ni80Fe20.
The in situ RHEED studies showed that the top and bottom Py layers were grown as nice Py(111) and in-between Cr layer was grown as Cr(110). For the Cr(110) layer however, there are two in-plane domains, namely KS and NW domains, due to the symmetry and lattice mismatches between the Cr(110) and Py(111) plane. The magnetic structure of the Py/Cr/Py trilayers was studied by LMOKE and neutron scattering. The results indicate that the coupling between the Py layer depends on the thickness of the Cr layer (tCr). Clear anti-ferromagnetic coupling was observe for tCr =2.5 nm. Detailed structural, magnetic and transport properties of the epitaxial Py/Cr/Py trilayers will be reported.

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