We studied tetragonally distorted Fe(1-x)Co(x) alloy films on Rh(001), which show a strong perpendicular anisotropy in a wide thickness and composition range. Analyzing x-ray magnetic circular dichroism spectra at the L_(3,2) edges we found a dependence of the Co magnetic orbital moment on the chemical composition of the Fe(1-x)Co(x) alloy films, with a maximum at x=0.6. For this composition, we observed an out-of-plane easy axis of magnetization at room temperature for film thickness up to 15 monolayers. Since both the magnetic orbital moment and the anisotropy energy show similar composition dependence, it confirms that both quantities are directly related. Our experiments show that the adjustment of the Fermi level by a proper choice of the alloy composition is decisive for the large magnetic orbital moment and for a large magnetic anisotropy in a tetragonally distorted lattice.

Tetragonally distorted FexCo1−x alloy films are grown on Rh (001) showing a strong perpendicular magnetic anisotropy in a wide thickness and composition range. This large perpendicular magnetic anisotropy is chemical composition dependent and reaches a maximum at x=0.4. For this composition, we observed an out-of-plane easy axis of magnetization at room temperature with film thickness up to 15 ML. Our experiments show that the proper adjustment of the Fermi level (EF) by the variation of the FexCo1−x alloy composition and the corresponding tetragonal distortion results in a large perpendicular magnetic anisotropy.

Magnetic properties of Fe/NiO bilayers grown on a (1,1,10) vicinal surface of Ag(001) were studied by magneto-optical Kerr effect (MOKE) and x-ray magnetic linear dichroism (XMLD). The orientation of the antiferromagnetically (AFM) aligned spins of NiO films shows an in-plane spin-reorientation transition (SRT) from parallel to perpendicular to the steps with increasing NiO thickness. Two in-plane SRTs of Fe moments are found in dependence of the NiO thickness. The first SRT of the Fe magnetization from parallel to perpendicular to the steps is observed at NiO thickness where antiferromagnetic order is found, the second at the NiO thickness of the SRT in the NiO film. Also, the in-plane SRT of Fe spins driven by a temperature increase is observed. The perpendicular coupling between the Fe and NiO spins is proven. The induced uniaxial anisotropy energy is estimated to be 0.12 erg/cm 2 .

High-resolution anisotropic magneto-resistance measurement (AMR) was used to detailed study the training effect in exchange biased CoO/Co bi-layer. The sample was cooled to 10 K from room temperature in the magnetic cooling field of 4000 Oe. Then we used 1500 Oe declined perturbation field to pin the magnetization orientation of the FM layer. The perturbation field forms certain angle Θ with the cooling field direction in-plane to re-induce the untrained state. The dependence of the untrained state on the angle between the direction of perturbation field and cooling field has been investigated. The AMR results reveal that the re-induced degree of untrained state is strongly correlated to the angle Θ. The exchange bias field H E for different Θ has been determined from the AMR results, which is in apparent agreement with the Meiklejohn-Bean model. The recover degree of untrained state is the largest when the angle is 75˚, which is different from the traditional view point that untrained state should be the maximum when it is perpendicular. The training effect is related to the FM spin orientation, which can induce the change of the interfacial AFM spin reorientation with different angles.

The influence of anisotropic strains on coupling spins is systematically investigated in pulsed laser deposited single crystal Pr5/8Ca3/8MnO3 film. The substrate was chosen to introduce tensile and compressive strain onto the film. Various experiments, i.e., zero field cooled/field cooled (ZFC/FC) magnetization measurement, hysteresis loops, and exchange bias field detection, have revealed distinct difference along two perpendicular in-plane axes which represent tensile and compressive strain orientation, respectively. We found that the observed phenomenon can be explained by the external strain effect.