Magnetic interface coupling in single-crystalline Co/FeMn bilayers

Abstract

The magnetic coupling between epitaxial single-crystalline Co and FeMn layers on Cu(001) was investigated by element-resolved magnetic circular dichroism domain imaging using a photoelectron emission microscope. As-grown Co domain patterns reveal the presence of many small domains in the antiferromagnet. The coupling of the Co layer is found to be along <100> crystallographic directions. This is discussed in terms of a 45degrees coupling due to frustrations at topological 90degrees domains in the FeMn layer. Coercivity oscillations as a function of FeMn thickness with atomic monolayer period support the importance of such step-induced domains in the coupling

Huge magnetocrystalline anisotropy of x-ray linear dichroism observed onCo∕FeMnbilayers

“…12 This provides an opportunity to study the magnetic properties of an AF/FM system in single crystalline FeMn/Co and Co/FeMn bilayers on Cu(001). 10,12,19 Scanning tunneling microscopy revealed atomically smooth interfaces with islands or vacancies of single atomic height. 20 Based on XMCD-PEEM investigations of FM/FeMn/FM trilayers and on XMLD spectroscopy experiments of Co/FeMn bilayers, we concluded previously that a non-collinear three-dimensional spin structure is present in the ultrathin FeMn layers, possibly similar to the so-called 3Q spin structure present in bulk FeMn.…”

Emergence of noncollinear anisotropies from interfacial magnetic frustration in exchange-bias systems

“…2 Moreover, engineering fully adjustable magnetic hysteresis, 10 as well as the use of nanostructures 11 or multifunctional materials, 12 have been recently demonstrated in exchange-coupled FM/AFM systems. In addition, there are a plethora of other magnetic phenomena associated in exchange-coupled FM/AFM systems, such as coercivity enhancements, 13,14 magnetization reorientation, [15][16][17] modified antiferromagnetic spin structures, 16,18,19 and asymmetric magnetization reversal, 20,21 which are not fully understood, 2 and often manifest themselves very differently for various material combinations. Prospects for control, tailor, and enhancement of desirable effects depend upon a clear understanding of the mechanisms governing exchange bias.…”

Construction of the Magnetic Phase Diagram of FeMn/Ni/Cu(001) Using Photoemission Electron Microscopy

“…First, in the region where FeMn changes from paramagnetic to antiferromagnetic ( ML) and Ni SRT takes place ( ML), the out-of-plane Ni domains breaks into relatively small domains. This phenomenon is similar to the domain change in Co/FeMn system, which is attributed to the establishment of the FeMnantiferromagnetic order [5]. This is an important signature of the FeMn AFM order because metallic FeMn does not generate X-ray Magnetic Linear Dichroism so that there is no effective way to measure the FeMn AFM order.…”

“…In an effort to minimize the interfacial roughness, single crystalline FeMn/Co/Cu(001) thin films have become one of the model systems for the study of interfacial interactions in AFM/FM system [4]. Previous studies show that the AFM order of the FeMn layer significantly affect the Co magnetic properties [5], [6]. The observed phenomena were well explained by the FeMn/Co interaction due to the presence of random atomic steps at the interface.…”