Types Of Exchange Coupling Research Articles

Strain-induced modulation of temperature characteristics in ferrimagnetic Tb\u2013Fe films

This study investigates the effect of strain on the compensation temperature of ferrimagnetic Tb–Fe films formed on a flexible substrate. The compensation temperature is determined by the anomalous Hall measurement, and an application of 1.2% tensile strain reduces the compensation temperature by 12 K. X-ray magnetic circular dichroism reveals that approximately 5% of Fe magnetic moment and approximately 1% of Tb magnetic moment are reduced by an application of 0.9% tensile strain at the room temperature. To understand the greater reduction in Fe magnetization compared with that in Tb and the compensation temperature reduction simultaneously, a model applying molecular field theory is analyzed. Changes in three types of exchange coupling between Fe and Tb atoms are speculated to be caused by the strain.

Sign reversal of spontaneous exchange bias in Mn0.7Fe0.3NiGe alloy

Spontaneous exchange bias can be observed at 5K after zero-field cooling in Mn0.7Fe0.3NiGe alloy. More interestingly, its sign can reverse from positive to negative with the increase of maximum measurement field. Such results indicate a coexistence of ferromagnetic and antiferromagnetic coupling formed at the ferromagnetism/spin glass interface during the initial magnetization process. Hence, the sign reversal would be resulted from the relative strength change of these two types of exchange coupling, which can be tuned by measurement field.

Interfacial Electronic Scattering in Fe/Cr Superlattices

The magnetorefractive effect (MRE) has been measured in the infrared spectral region of 1.2-28 μm in MBE-grown Fe/Cr superlattices with variable Fe and Cr layers thicknesses inp-polarized light. The magnetic and magnetooptical properties have been studied as well. From the MRE spectra modeling in the framework of magnetoreflection theory for multilayered structures, the parameters of interfacial spin dependent scattering of conductivity electrons have been defined for different types of exchange coupling between adjacent Fe layers. The dependence of interfacial scattering parameters on Fe and Cr layer thickness is discussed.

Micromagnetic modeling of magnetization reversal of Fe/Cr/Co exchange coupled multilayers (abstract)

Multilayers consisting of Fe/Cr/Co were prepared under molecular beam epitaxial condition on MgO substrates. These kind of multilayers exhibit different types of exchange coupling with respect to the Cr spacer thickness. We have studied the samples by means of magnetooptic Kerr microscopy as well as Brillouin light scattering and additional MOKE characterization. The investigations were performed on samples with homogeneous Cr spacer thickness and also on wedge type samples. From light scattering experiments we were able to locate the ferromagnetic and the antiferromagnetic coupled regions in the wedged sample. We obtained a switching field for the antiferromagnetic coupled layers of the order of 100 kA/m. Detailed MOKE studies revealed an fourfold inplane anisotropy with collinear axes of Co and Fe layers. In order to get insight in the magnetization reversal process in such multilayers, we studied the magnetic domain dynamics simultaneously to the measurement of hysteresis loops using magnetooptic Kerr microscopy. Based on the results we developed a micromagnetic model which includes the anisotropy as well as the coupling through the Cr spacer layer. A refined numerical analysis for the different regimes of coherent rotation of the individual layers and domain wall propagation in the hysteresis loops yield the contribution of bilinear and biquadratic coupling with respect to the Cr spacer thickness. In conclusion we found oscillation of the interlayer exchange coupling with varying coupling strength.