liu.seSearch for publications in DiVA
Change search
ReferencesLink to record
Permanent link

Direct link
Effect of phase formation on valence band photoemission and photoresonance study of Ti/Ni multilayers using synchrotron radiation
UGC-DAE Consortium for Scientific Research, Indore, India.
UGC-DAE Consortium for Scientific Research, Indore, India.
2006 (English)In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, Vol. 15, no 1-2, 56-66 p.Article in journal (Refereed) Published
Abstract [en]

This paper presents investigation of Ti–Ni alloy phase formation and its effect on valence band (VB) photoemission and photoresonance study of as-deposited as well as annealed Ti/Ni multilayers (MLs) up to 600 °C using synchrotron radiation. For this purpose [Ti (50 Å)/Ni (50 Å)]X10 ML structures were deposited by using electron-beam evaporation technique under ultra-high vacuum (UHV) conditions. Formation of different phases of Ti–Ni alloy due to annealing treatment has been confirmed by the X-ray diffraction (XRD) technique. The XRD pattern corresponding as-deposited ML sample shows crystalline nature of both Ti and Ni deposited layers, whereas 300 °C annealed ML sample show solid-state reaction (SSR) leading to amorphization and subsequent recrystallisation at higher temperatures of annealing (≥400 °C) with the formation of TiNi, TiNi3 and Ti2Ni alloy phases.

The survey scans corresponding to 400, 500 and 600 °C annealed ML sample shows interdiffusion and intermixing of Ni atoms into Ti layers leading to chemical Ti–Ni alloys phase formation at interface. The corresponding recorded VB spectra using synchrotron radiation at 134 eV on as-deposited ML sample with successive sputtering shows alternately photoemission bands due to Ti 3d and Ni 3d, respectively, indicating there is no mixing of the consequent layers and any phase formation at the interface during deposition. However, ML samples annealed at higher temperatures of annealing, particularly at 400, 500 and 600 °C show a clear shift in Ni 3d band and its satellite peak position to higher BE side indicates Ti–Ni alloy phase formation. In addition to this, reduction of satellite peak intensity and Ni 3d density of states (DOS) near Fermi level is also observed due to Ti–Ni phase formation with higher annealing temperatures. The variable photon energy VB measurements on as-deposited and ML samples annealed at 400 °C confirms existence and BE position of observed Ni 3d satellite structure. The observed changes and modifications in the VB photoemission are discussed and interpreted in terms of structural changes at the interface due to annealing treatment.

Place, publisher, year, edition, pages
2006. Vol. 15, no 1-2, 56-66 p.
Keyword [en]
Ti/Ni multilayer; PES; Synchroctron radiation; Valence band; Annealing; Alloy phase formation
National Category
Natural Sciences
URN: urn:nbn:se:liu:diva-13115DOI: 10.1016/j.elspec.2006.03.006OAI: diva2:17862
Available from: 2008-04-01 Created: 2008-04-01 Last updated: 2010-06-14
In thesis
1. Fabrication and study of inorganic and organic thin film magnets
Open this publication in new window or tab >>Fabrication and study of inorganic and organic thin film magnets
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Thin film magnets are very important for many kinds of electronic devices and play a crucial role to achieve optimum performance. Therefore an intense level of research is going on all around the world to fabricate advanced electronics devices using both new inorganic and organic thin-film magnets. Historically, most magnetic materials used for technological applications are based on inorganic materials and have been studied extensible up to now. Recently, however, organic or molecular magnets have opened a new prospective of thin film magnets which have begun to show promise, offering the possibility of light-weight flexible materials and devices that include magnetic functionality.

The research presented in this thesis is hence divided into two parts, where inorganic and organic magnets in thin films form were studied. The Ti/Ni multilayer system is studied as an inorganic magnet in the first part, whereas M(TCNE)x thin films were studied in the second part with M= Fe, Ni and TCNE is tetracynoethelene, an organic compound, and x~2.

The Ti/Ni multilayer is a potential candidate for industrial applications and also features solid-state amorphisation. Because of various interesting scientific and technological aspects of Ti/Ni multilayer structures, many structural properties and subsequent thermal stability studies have been extensively reported in the literature, but surprisingly few reports are available on the corresponding electronic and magnetic properties. The work in the present thesis is therefore focused on synthesis and systematic investigation of structural, electronic and magnetic properties of as prepared as well as annealed Ti/Ni multilayer structures and to establish correlation between them.

The second part of the thesis deals with organic-based molecular magnets of the M(TCNE)x type, where x~2, M = Fe, Ni and TCNE = tetracynoethelene. Fe(TCNE)x and Ni(TCNE)x have for the first time been fabricated as thin films, free of oxygen- and precursor-induced defects. The films were fabricated in situ under ultra high vacuum conditions using our group’s recently developed fabrication techniques for organic-based molecular magnets. The previously unknown electronic structure of these thin film magnets are presented in the thesis. Room temperature magnetic ordering was observed for thin films of Ni(TCNE)2, in stark contrast to earlier versions of the material (fabricated with the old methods and hence containing various defects). Room temperature magnetic ordering for a similar system, Ni2(TCNE), previously has been reported by another group, but it is clear that more studies are necessary to completely resolve the underlying mechanisms for the magnetic properties seen in these materials.

Place, publisher, year, edition, pages
Linköping: Institutionen för teknik och naturvetenskap, 2007. 65 p.
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1152
Physics, electronic, thin films, inorganic magnets, organic magnets
National Category
Physical Sciences
urn:nbn:se:liu:diva-11442 (URN)978-91-85895-20-5 (ISBN)
Public defence
2007-12-14, K3, Kåkenhus, Campus Norrköping, Linköpings universitet, Norrköping, 10:15 (English)
Available from: 2008-04-01 Created: 2008-04-01 Last updated: 2012-11-21

Open Access in DiVA

No full text

Other links

Publisher's full textLink to Ph.D. thesis

Search in DiVA

By author/editor
Bhatt, Pramod
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 58 hits
ReferencesLink to record
Permanent link

Direct link