Interface induced magnetic properties of Gd/Co heterostructures

Abstract

Antiferromagnetic coupling between rare-earth and transition metal ferromagnetic layers gives rise to various magnetic ground states in heterostructures of these materials. Interface structure and morphology tend to play important roles in magnetic properties of such systems. Interface induced magnetization in Gd/Co heterostructures has been studied using a combination of structural and magnetic characterization techniques. The interface morphology of the Gd/Co system was varied by growing Gd/Co multilayers using magnetron sputtering under different argon partial pressures. Interfacial properties were further modified by annealing the multilayers under high vacuum. The macroscopic magnetization measurements have been correlated with depth dependent structure and magnetic properties of multilayers studied using X-ray and polarized neutron reflectometry techniques. Secondary ion mass spectrometry measurements from both as-deposited and annealed samples also confirmed modification at the interfaces. It has been shown that the interface structure, together with roughness, leads to a unique low-temperature magnetic phase characterized by twisting of Gd and Co moments.

Antisymmetric magnetoresistance and helical magnetic structure in a compensated Gd/Co multilayer

“…However, Co has grown with a polycrystalline hcp structures. These results are consistent with an earlier study on Gd/Co multilayers grown on glass substrates [29]. Fig.…”

Interface morphology driven exchange interaction and magnetization reversal in a Gd/Co multilayer

“…1(a) shows the GIXRD pattern (intensity in log scale) for Gd/Co in the pristine and annealed (at 573 K) conditions, which shows a similar pattern with fcc and hcp structures for Gd and Co, respectively, and is consistent with earlier measurements. 28,29,31 The Bragg peaks are labelled for different reflections from a crystalline phase of Gd and Co. In Fig.…”

“…The other growth parameters were kept similar to those reported earlier. 29 The inset of Fig. 1(a) represents the layered structure of the pristine multilayer.…”

“…23,24 Thus the spin configurations like helices in the form of planar DW structures with stable magnetic properties in the exchange-coupled RE-TM systems near the compensation temperature is the key to manipulating high-speed magnetic devices. 25–27 Recently the realization of a twisted helical magnetic structure with planar 2π DWs and highly correlated magnetic domains in Gd/Co multilayers 28–31 and other RE-TM systems 5,27,32 has been reported. In addition, a double hysteresis loop (DHL) and an exchange bias (EB) were also observed in these RE-TM heterostructure systems, which was attributed to the depth-dependent magnetic helical structures.…”

“…5,27,28,31,32 The interface structure and morphology have been found to play a vital role in determining the temperature-dependent magnetic configuration and phases in the Gd/TM based multilayers. 6,7,28–31 Here we report the influence of the interface morphology on the evolution of the macroscopic magnetic properties, i.e. , exchange bias field ( E B ), coercive field, compensation temperature ( T comp ), and a vertical shift in the magnetization curve, in the Gd/Co multilayer across the T comp , by combining the experimental methods and theoretical calculations using a one-dimensional-spin based model.…”