GMR in Excess of 10% at Room Temperature and Low Magnetic Fields in Electrodeposited Cu/Co Nano-Multilayer Structures Dinesh K. Pandya, Priyanka Gupta, Subhash C. Kashyap, and Sujeet Chaudhary Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India ABSTRACT Electrodeposition has emerged as a novel economically viable technique with large-scale production capabilities in modern day micro technologies. The current trends are to extend the potential of electrodeposition to nano fabrication. We have successfully electrodeposited Cu/Co multilayers, exhibiting appreciably high GMR, on ITO as well as on Cu/Si substrates. Multilayer stacks with films in the thickness range of 1 – 10 nm were electrodeposited. The Co layers have different mechanisms of growth on these substrates, thus resulting in different microstructure and topography of the electrodeposited films. This leads to different GMR behavior of the multilayers in both these cases. Room temperature GMR values of 15% at low fields are obtained on ITO substrate and higher values are possible on Cu/Si substrate. INTRODUCTION Magnetic multilayers, exhibiting giant magnetoresistance (GMR), are some of the first nanostructures which have been incorporated into the production of read heads for reading data on a hard disk. Co/Cu multilayers (MLs), comprising of non-magnetic spacer layer of Cu sandwiched between the ferromagnetic layers of Co, are known to have high application and potential for spin based high-density information storage devices [1]. Thus a quest for a simple method for fabricating these multilayers exhibiting high GMR is driving the research in this area. Electrodeposition (ED), because of its cost-effectiveness, simplicity and ability to deposit films on large areas as well as in nanopores, is proving to be a viable technique nowadays. The crucial aspects in the growth of MLs by ED are the microstructure, thickness of individual layers and the interfacial roughness [2], as these parameters play a very crucial role in deciding the resistive and magnetic behavior of multilayers. These are in turn controlled by the bath parameters such as concentration of Cu 2+ and Co 2+ , additives [3], and pH [4]. The role of a substrate used to deposit films is also significant, as it influences the nucleation and growth, and hence the microstructure of thin films. In the present work, we have made an attempt to understand the dependence of GMR vis-a-vis roughness of the substrates and related film topography, and the role of Co layer in controlling the GMR behavior, in electrodeposited Cu/Co multilayers. EXPERIMENTAL Multilayers of Co/Cu have been electrodeposited in potentiostatic mode, using a single sulphate bath. The multilayers were grown on ITO coated glass substrates and on n-type Si coated with Cu seed layer (i.e. Cu/Si). Details of the deposition bath have been reported elsewhere [5]. Mater. Res. Soc. Symp. Proc. Vol. 961 © 2007 Materials Research Society 0961-O12-03