Room temperature synthesis of nanocrystalline ferrite MFe 2 O 4 ,M  Cu, Co and Ni) thin ®lms using novel electrochemical route S.D. Sartale a , G.D. Bagde a , C.D. Lokhande a,* , M. Giersig b a Department of Physics, Thin Film Physics Laboratory, Shivaji University, Kolhapur 416 004, India b Hahn-Meitner-Institute, Glienicker Strasse 100, D-14109 Berlin, Germany Abstract An electrochemical route is depicted as a novel and powerful route for the synthesis of nanocrystalline ferrite MFe 2 O 4 , M  Cu, Co and Ni) thin ®lms onto various conducting substrates. MFe 2 alloy ®lms were galvanostatically electrodeposited onto various conducting substrates using simple aqueous and non-aqueous ethylene glycol) sulfate baths. Further anodization of these alloy ®lms at room temperature 278C) in aqueous 1N KOH electrolyte has been carried out to convert them into oxide MFe 2 O 4 ) ®lms. The ferrite thin ®lms were characterized by means of X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy HRTEM) techniques. It is observed that the ®lms have uniform and homogeneous surface with spinel cubic structure except for CuFe 2 O 4 tetragonal). The grain size of the ®lm material is found in between 10 and 50 nm. # 2001 Elsevier Science B.V. All rights reserved. Keywords: Nanocrystalline ferrite thin ®lms; Room temperature synthesis; XRD; SEM; HRTEM 1. Introduction Technologyinthe21 st centuryrequiresofdevicesof nanometersizewherebytheperformancecanbeenhan- ced dramatically [1]. Nanocrystalline 10±50 nm) fer- rite thin ®lms with the spinel structure have been the subject of extensive investigation because of their potential applications in high-density magneto-optic recordingdevices,colorimaging,bioprocessing,mag- netic refrigeration and ferro¯uids [2,3]. The recent discoveries of giant magneto resistance GMR) and macroscopic quantum tunneling have attracted addi- tional attention to these materials regarding their potentialuseinmagneticrecordingandmagneto-optic devices [4,5]. Present techniques such as vacuum evaporation, sputtering, sol±gel, spray pyrolysis, etc.) so far used for the preparation of ferrite thin ®lms require sub- strate heating at temperature higher than several hun- dred degree celsius for crystallization. Therefore, the substrate should not have only high heat resistance but also a thermal expansion coef®cient that con®rms to that of deposited material and does not allow the deposition on devices that might degenerate after exposure to a high temperature. All these methods require expensive equipments for a high degree of control and there is waste of material. Also the ®lm particles obtained by these methods are rather larger and non-uniform in size. On sintering non-reproduci- ble products and toxic gases are produced. However, Applied Surface Science 182 2001) 366±371 * Corresponding author. Tel.: 91-231-690571; fax: 91-231-691533. E-mail address: l_chandrakant@yahoo.com C.D. Lokhande). 0169-4332/01/$ ± see front matter # 2001 Elsevier Science B.V. All rights reserved. PII:S0169-433201)00450-0