Camarero J, Pennec Y, Vogel J, Bonfim M, Pizzini S, Ernult F, Fettar F, Garcia F, Lançon F, Billard L, Dieny B, Tagliaferri A, Brookes N B
Laboratoire Louis Néel, CNRS, BP166, 38042 Grenoble Cedex, France.
Phys Rev Lett. 2003 Jul 11;91(2):027201. doi: 10.1103/PhysRevLett.91.027201. Epub 2003 Jul 7.
An in-plane perpendicular magnetic coupling between Ni80Fe20 and Co has been found in NiFe/NiO/Co trilayers for a NiO thickness ranging from 4 to 25 nm by magneto-optical Kerr effect and x-ray magnetic circular dichroism measurements. In the easy magnetization direction of the Co layer, the Co coercive field H(C) increases when the thickness of the NiO layer t(NiO) increases. Because of the coupling, H(C) is always larger than for NiO/Co bilayers with the same thicknesses. The saturation field of the NiFe layer H(S) decreases when t(NiO) increases, indicating a weakening of the coupling. Numerical simulations show that the presence of interface roughness combined with a small value of the NiO anisotropy can explain the observed 90 degrees coupling.
通过磁光克尔效应和X射线磁圆二色性测量发现，在NiFe/NiO/Co三层膜中，当NiO厚度在4至25纳米范围内时，Ni80Fe20和Co之间存在面内垂直磁耦合。在Co层的易磁化方向上，当NiO层厚度t(NiO)增加时，Co矫顽场H(C)增大。由于这种耦合，H(C)总是大于相同厚度的NiO/Co双层膜的矫顽场。当t(NiO)增加时，NiFe层的饱和场H(S)减小，表明耦合减弱。数值模拟表明，界面粗糙度的存在以及NiO各向异性的小值可以解释所观察到的90度耦合。
