Giant magnetoresistance (GMR) in electrodeposited multilayer films: the influence of superparamagnetic regions

Bakonyi, Imre and Péter, László and Weihnacht, V. and Tóth, József and Kiss, László (2005) Giant magnetoresistance (GMR) in electrodeposited multilayer films: the influence of superparamagnetic regions. JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, 7 (2). pp. 589-598. ISSN 1454-4164

Preview

Text 1169379.pdf Download (130kB) | Preview

Abstract

When preparing an alternating sequence of magnetic (Co or Ni) and non-magnetic (Cu) layers by electrodeposition using the two-pulse plating technique, a dissolution of the lessnoble magnetic Co and Ni atoms can take place during the deposition of the more noble and non-magnetic Cu atoms. This process results in changes of the actual sublayer thicknesses with respect to the nominal values and can also cause some chemical intermixing at the magnetic/non-magnetic interfaces. As a consequence, superparamagnetic (SPM) regions with “loose magnetic moments” can form as has been demonstrated for electrodeposited Ni-Cu/Cu multilayers. We have also shown recently for electrodeposited Co-Cu/Cu multilayers that if some fraction of the magnetic layers exhibits SPM behaviour then the observed giant magnetoresistance (GMR) can be quantitatively decomposed into a ferromagnetic (FM) and a SPM contribution. In this paper, the results of a similar GMR decomposition study are presented for two electrodeposited Co-Cu/Cu multilayers. In the multilayer with strongly non-saturated magnetoresistance curves, the dominant GMR term was due to SPM regions, whereas in the other multilayer for which the magnetoresistance is mostly saturated in magnetic fields around 1 to 2 kOe, the FM contribution to the GMR is much larger. At the same time, magnetic measurements on the first multilayer sample have also revealed the presence of a large SPM contribution to the magnetization.

Actions (login required)

Edit Item