Interfacial atomic diffusion in AF/Fe/Cu/Fe (AF = Fe 50 Mn 50 and Ir 50 Mn 50 ) multilayer systems V. Kuncser a, ⁎, W. Keune b,c , U. von Hörsten b , G. Schinteie a , N. Stefan d , P. Palade a , G. Filoti a a National Institute of Materials Physics, P.O. Box MG 7, 77125, Bucharest-Magurele, Romania b Fakultät für Physik, Universität Duisburg-Essen (Campus Duisburg), D-47048 Duisburg, Germany c Max-Plank-Institut für Mikrostrukturphysik, D-06120 Halle, Germany d National Institute for Lasers, Plasma and Radiation Physics, 07712, Bucharest-Magurele, Romania abstract article info Article history: Received 1 September 2009 Received in revised form 24 April 2010 Accepted 21 May 2010 Available online 1 June 2010 Keywords: Interfacial atomic diffusion Multilayers Conversion Electron Mössbauer Spectroscopy Spin valve like AF/Fe/Cu/Fe (AF= Fe 50 Mn 50 and Ir 50 Mn 50 ) multilayer systems have been prepared by molecular beam epitaxy. Thin tracer layers enriched in the 57 Fe isotope were artificially grown at the AF/Fe and Fe/Cu interfaces and the interfacial atomic diffusion was observed via 57 Fe conversion electron Mössbauer spectroscopy. The results show that the atomic interdiffusion at all involved interfaces is lower in the IrMn based structures as compared to the FeMn based ones. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Magnetic recording has sharply progressed over the last five decades. The amount of information per unit area has increased by more than seven orders of magnitude, e.g., from 2 kbits/in 2 in 1956 to more than 100 Gbits/in 2 in the present disks [1]. This impressive achievement was connected with an important progress in decreasing the bits (seen as small magnetized regions) as well as in decreasing the size of the writing/reading elements [2]. Today's magneto- resistive elements are based on Giant Magneto-Resistance (GMR) or Tunneling Magneto-Resistance effects [3,4]. The main component of such an element is the spin-valve structure. Among the presently used structures, the most convenient one consists of a stack of ferromag- netic (F), antiferromagnetic (AF) and non-magnetic (NM) metallic thin films [5]. The simplest stack of a GMR based element (which is in fact also its active part) is of type AF/F/NM/F, generally with NM = Cu. The electron transport through the Cu conductive thin layer is controlled via the relative orientation of the spins (or magnetizations) in the adjacent F layers. The switching from the parallel to the antiparallel magnetic configuration of the two F layers is realized via the application of a small magnetic field (e.g., generated by the magnetic bits). The magnetic behavior of the F layer coupled to the AF layer is influenced by the exchange bias effect [6] which is related to the unidirectional anisotropy induced, under certain conditions, at the AF/F interface. Macroscopically, the effect may manifest itself by a negative or positive shift of the hysteresis loop of the coupled F layer as well as by an increased coercivity (the latter being connected with a uniaxial anisotropy). The shift of the loop from zero field is called exchange bias field, H E . Therefore, the complex loop of the above mentioned spin-valve structure can be decomposed into the shifted hysteresis loop of the coupled F layer and the loop of the free F layer which is centered at zero field. During the magnetization reversal process, the spin orientation in the two F layers can be similar or opposite, depending on the value of the applied field with respect to H E . The exchange bias field, as one of the crucial parameters of a spin- valve structure, may be roughly expressed via the relationship: H E =σ / M r t where σ is the interfacial exchange energy, M r the remanent magnetization of the pinned F layer and t its thickness [1]. Evidently, both the interfacial exchange energy and the remnant magnetization depend on many other variables such as the type of the F and AF films, their crystalline structure and phase composition, the quality of the AF/F interface, etc. [7–10]. In addition, also the electron transport through the conductive layer can be drastically influenced by the F/Cu interface on the both sides of the Cu layer. Hence, the quality of all interfaces of the multilayer structure becomes of main importance in regard to different aspects of its GMR behaviour. Convenient AF pinning layers in giant magneto-resistive elements consist in either equatomic Fe–Mn alloys with fcc structure or in Mn rich Ir–Mn alloys with similar structure, but with a relatively improved corrosion resistance and lower critical thickness. The present paper deals with a study of the interfacial atomic diffusion mechanisms in stacks of type AF/Fe/Cu/Fe, by 57 Fe conversion electrons Thin Solid Films 518 (2010) 5981–5985 ⁎ Corresponding author. Tel.: +40 21 369 01 85; fax: +40 21 369 01 77. E-mail address: kuncser@infim.ro (V. Kuncser). 0040-6090/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.tsf.2010.05.100 Contents lists available at ScienceDirect Thin Solid Films journal homepage: www.elsevier.com/locate/tsf