Study of the interfaces between magnetic thin films and antiferromagnetic substrates by synchrotron radiation photoelectron emission microscopy

光电发射电子显微镜（PEEM）设备在我们的实验室在光子工厂光束线，筑波，用于磁畴成像。结合光子能量的圆磁二色性和线性磁二色性以及光子能量的可调性，我们可以获得铁磁和反铁磁材料的元素特定域图像。这一优势使我们不仅可以获得薄膜的信息，还可以获得基板和界面的信息。然而，为了充分利用这一优势，样品应该在各种温度下在平面上自由而精确地旋转。为此，我们设计了一种新的样品机械手。在这个项目期间，我们主要在光子工厂的BL11A， 13C和2C光束线上进行实验。底物为NiO（100）。在衬底上沉积了Cr或Fe薄膜。对于Cr/NiO（100）体系，我们发现了NiO反亚磁畴的调制对比度是Cr厚度的函数。这可能源于Cr和Ni磁矩之间的交换耦合。在Cr的奇数层厚度区域，NiO磁畴对比度降低，而在偶数层区域对比度保持不变。假设在奇层Cr区存在净磁化，而在偶层Cr区无磁化。因此，只有在奇层区域，对比度才可能被抑制。铁吗?在NiO（100）体系中，我们发现了Fe薄膜中非常复杂的畴结构随厚度的变化而变化。这也源于薄膜与衬底之间的交换耦合，但进一步考虑薄膜本身能量的各向异性引起的畴结构。我们进一步发现t畴（源于反铁磁晶体畸变引起的孪晶结构）不受薄膜沉积的影响，而s畴（源于自旋结构）受到强烈影响。这种现象可以通过对Ni-L边缘和O-K边缘的畴的比较观察来区分。我们还在SPring-8 （BL-23 SU， 25SU和27SU）的光束线上进行了实验，在这些光束线上安装了比PF更高性能的peem。我们清楚地区分了NiO的t和s域。我们进一步成功地观测到比以前报道的更丰富的详细的x射线吸收光谱。这一成功是通过对NiO未损伤表面的微观测量完成的。少

Photoemission Electron Microscope (PEEM) equipment operated at our laboratory in the Photon Factory beamline, Tsukuba, is used for the magnetic domain imaging. Combining the merits with the circular and linear magnetic dichroism effects and tunability of the photon energy, we can obtain the element specific domain images both for ferro-and antiferromagnetic materials. This advantage allows us to get the information not only for thin films but also for substrates and interfaces. However, in order to use this advantage completely, samples should be rotated freely and precisely in plane and for a variety of temperature. We designed a new sample manipulator for this purpose.During the period of this project, we mainly perform the experiments at the beamline BL11A, 13C and 2C of the Photon Factory. The substrate was NiO(100). Cr or Fe thin film was deposited onto the substarate. For the Cr/NiO(100) system, we found the modulation contrast of the NiO antifferomagnetic domain as a function of … More Cr thickness. This may originates from the exchange coupling between the Cr and Ni magnetic moments. In odd monolayer thickness regions of Cr, the NiO magnetic domain contrast decreases whereas the contrast remains in even layer regions. It is supposed that the net magnetization exists in odd layer Cr region and no magnetization in even layer regions. Therefore, only at the odd layer region, the contrast may be suppressed. For Fe?NiO(100) system, we found out very complicated domain structures in Fe thin film as a function of the thickness. This also originates from the exchange coupling between the film and the substrate, but further, we should consider the domain structures caused by the anisotropy energy of film itself. We further found out the T-donain (originating from twin structure due to antiferromagnetic crystal distortion) is not affected by the film deposition whereas the S-domain (originating from spin structure) is strongly affected. This phenomenon is distinguished by the comparative observation of domains at Ni-L edge and O-K edge.We also perform the experiment at the beamlines at SPring-8 (BL-23 SU, 25SU and 27SU), where the higher performance PEEMs are installed than at the PF. We clearly distinguished the T-and S-domains of NiO. We further succeeded to observe detailed X-ray absorption spectra with richer features than those reported previously. This success was done by the microscopic measurements from the non-damaged surface area of NiO. Less