The interlayer exchange interaction in multilayer magnetic systems Fe/Cr/Fe (Review Article)

Abstract

Upsurge of interest in the study of magnetic multilayer structures began in the mid-80s of the twentieth century and was caused by significant progress in the technology of ultrathin metallic films. For a few years, phenomena extremely interesting from both fundamental and applied point of view have been found in these structures: the antiparallel arrangement of the ferromagnetic layers, giant magnetoresistance, alternating oscillations of the interlayer exchange, noncollinear interlayer ordering of magnetic moments. All this and the closeness of technologies, used for the sample preparation to those traditionally applied in microelectronics, promised great potentials for developing compact magnetic field sensors, non-volatile memory for electronic devices, etc. To date, some of these features are already implemented in the mass commercial products (e.g., read heads of hard drives), and others still wait in the wings. The Nobel Prize, awarded in 2007 to A. Fert and P. Grünberg with the words “For the discovery of the giant magnetoresistance effect” can be considered as recognition of the importance of the discoveries made in this area. A special place in these works was given to the Fe/Cr/Fe system. It is there for the first time almost all of the most interesting phenomena were observed that caused a boom in the physics of magnetic films. However, until recently the nature of the exchange interaction in this system aroused great debates. First of all, it was due to a complex phase diagram of chromium spacer and strong influence on the sample properties of technological perfection of its structure. Here we made a brief review of the main experimental and theoretical studies on the multilayer systems Fe/Cr/Fe, as well as recounted the results of our own studies (performed with a group of co-authors), which greatly clarify the mechanism of the interlayer interaction in this system.