Effects of Interface Roughness on Interlayer Coupling in Fe/Cr/Fe Structure

Abstract

Effect of interface roughness on antiferromagnetic coupling between Fe layers in a Fe/ Cr/Fe trilayer, with Cr layer having a wedge form has been studied. All the samples have been deposited simultaneously on substrates having different roughness, thus it is being considered that there is no variation in the morphological features like grain size and grain texture of the films. Measurements have been done as a function of Cr spacer layer thickness and the peak value of antiferromagnetic coupling strength is compared among different trilayers, thus any influence of spacer layer thickness fluctuation from sample to sample has also been avoided. The samples are characterized by X-ray reflectivity (XRR) and magneto-optic Kerr effect (MOKE). XRR results show that the roughness of the substrate is not replicated at the successive interfaces. Antiferromagnetic coupling between Fe layers decreases with the increase of roughness of Fe/Cr/Fe interfaces.

Interlayer exchange coupling of Fe/Cr/Fe thin films on rippled substrates

“…16 This so-called Néel coupling deals with two separated semi-infinite ferromagnetic layers with in-plane magnetization and sinusoidally modulated surfaces and aligns both magnetizations parallel to each other, in case of conformal interface modulation at all interfaces of the trilayer stack. Usually this is the case for stacked layer systems and has been observed in the past in several experiments on rough 11,14 as well as patterned surfaces with a step-like modulation. 14,17,18 However, only micrometer-sized surface modulations could be achieved and were investigated.…”

“…[4][5][6][7][8][9][10] On one hand, an increasing interfacial roughness leads to a decrease in the bilinear antiferromagnetic coupling strength. 11 On the other hand, dipolar interactions are introduced to the system 12 as well as spatial fluctuations 13 both leading to an increase in the biquadratic coupling strength. Using recent ion irradiation techniques to modify the interfaces after deposition the IEC can be tuned as well.…”

Surfactant induced symmetric and thermally stable interfaces in Cu/Co multilayers

“…Figure 6 shows MOKE hysteresis loops of samples A and B. The AF coupled region of the multilayer contributes to magnetoresistance (MR) and is quantified by the AF fraction (AFF) given by AFF = 1 − (M r /M s ), with M r and M s being remanent and saturation magnetization, respectively [53][54][55]. The AFF for sample A is about 7%, and in sample B it increases to a value of about 12%.…”

Effect of surface morphology on magnetization dynamics of cobalt ultrathin films: An in-situ investigation

“…Moreover, a systematic modification of roughness and morphology is major requirement for better realization of underlying effects. In the view of the above fact, magnetic thin films and multilayer structures have been extensively studied in literature [17] [18][19] [20] [21] . However, investigations of this kind are still in the progress.…”