( An Autonomous Institution of University Grants Commission, New Delhi )
Few Related Publications
“Design, Development and Performance of UHV Chamber for in-situ Magneto-optic Kerr Effect and Resistivity Measurements” Dileep Kumar, S Potdar, V.R. Reddy and A Gupta, Vacuum Science and Technology Conference Series 114 (2008) 012034.
“Interface induced perpendicular magnetic an structure: An in-situ MOKE investigation” Dileep Kumar, Ajay Gupta, P. Patidar, K.K Pandey, T. Sant, and S.M Sharma arXiv:1208.3673v1 [cond-mat.mtrl-sci] 2012.
“In-situ study of magnetic thin films on nanorippled Si (1 0 0) substrates” Sarathlal K.V., Dileep Kumar, V. Ganesan, Ajay Gupta, Applied Surface Science 258 (2012) 4116.
“Growth study of Co thin film on nanorippled Si(100) substrate” Sarathlal K. V., Dileep Kumar, and Ajay Gupta, Appl. Phys. Lett., 98 (2011) 123111
“Study of ultrathin magnetic cobalt Films on MgO(001)” Gagan Sharma, U.P. Deshpande, Dileep Kumar and Ajay Gupta, J. Appl. Phys. 112 (2012) 023910.
How to use this facility (click here)
Electron gun with 3kW power and three crucibles is used to deposit thin films.
The distance between the e-gun and substrate holder is about 35 cm, which provide film thickness uniformity of 1% over 3 cm diameter substrate
MOKE measurements can be done simultaneously during the deposition.
The sample holder is attached to a rotary feed through which provides azimuthal angle dependence of the magnetic properties.
A double crystal quartz thickness monitor is being used to monitor the thickness of the thin film during film deposition.
Magnetic field is produced using vacuum compatible Helmholtz coils, which is most suitable for soft magnetic thin film because of negligible remanent filed.
Minimum step of the magnetic filed which can be achieved through computer controlling is less than 0.2 Oe.
The substrate is placed between the coils and always remains parallel to the applied field (even with sample rotation).
Setup Specification :
Vacuum during deposition: ~1×10-8 mbar
Deposition technique: Electron beam evaporation (EB)
Characterization technique: MOKE
Thickness measurement: using crystal monitor
Maximum field: ~250 Oe
In-situ heater with max temp.: 500°C
In-situ Magneto-Optic Kerr Effect (INS-MOKE)
Dr. Dileep Kumar
“Magneto-optic Kerr effect is one of the most powerful and widely used techniques for the analysis of the magnetic thin films in the field of spintronics. It is based on the Kerr effect, described by the Reverend John Kerr in 1877 [J. Kerr, Philos. Mag. J. Sci. 5, 321(1877)], which consists of the rotation of the polarization plane of a light beam when reflected from a magnetized surface. The magnitude of this change in polarization is proportional to the magnetization of the sample”
In general most of the basic studies in this field are either performed ex-situ or in embedded systems, where the ultrathin magnetic film is covered with a protective nonmagnetic layer. However, in both the cases, the oxidation of the surface or nonmagnetic protective layer can significantly modify the magnetic as well as transport properties
In contrast to ex-situ studies, in-situ MOKE studies under UHV condition provides actual property of ultra thin magnetic layer itself without an over layer.
Furthermore ex-situ measurements, as a function of film thickness, involve growing a series of samples of varying film thickness. Whereas, by continuously monitoring the magnetic and transport properties of a growing magnetic film in-situ, a detailed thickness dependent behavior can be obtained during growth of a single sample.