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AhadTalukder

Ahad Talukder: Influence of oxygen flow on the microstructure, resistivity, and Faraday rotation of reactive RF sputtered NiO and Fe-doped NiO thin films.

Md. Abdul Ahad Talukder


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Influence of oxygen flow on the microstructure, resistivity, and Faraday rotation of reactive RF sputtered NiO and Fe-doped NiO thin films.

                 

 

Yubo

Ahad Talukder.

 

Texas State University at San Marcos, Department of Physics, RFM 2225, 601 University Drive, San Marcos, TX78666.

 

Ahad Talukder

 

 

The effect of oxygen flow during deposition on the crystallinity, resistivity, and magneto-optical properties were studied for reactive sputtered thin NiO and Fe-doped NiO films. A series of NiO and Fe-doped NiO samples with different oxygen concentration were made using the RF sputtering technique at room temperature on different types of substrates. In terms of deposition pressure two types of sample were made: one type was sputtered at ̴1mTorr and the other at ̴7-8mTorr. Film thickness and roughness were measured using the variabl e angle spectroscopic ellipsometry and the XRR technique. Thickness values determined with both techniques are found to be close to each other. From the XRD peak analysis of both type of samples crystal size was calculated using the Scherrer equation and the inhomogeneous micro-strain was calculated using Stokes and Wilson approximation. A Pole Figure Analysis method which shows the dominating textures in the thin film was also done. A near surface analysis was done to get a true idea of the defects i.e. oxygen or metal vacancies in the thin films by using the Rutherford Backscattering Spectrometry (RBS). To measure the electrical properties, specifically the resistivity, the four-point probe method was used. The magneto-optical (MO) hysteresis loop were measured to determine the magnetic properties of the films. The MO Faraday data on the samples confirm preliminary results obtained by Twagirayezu [109] on these type of samples. As the magnetic signal on these samples was expected to be very small if at all present, a large effort was spent on improving the measurement setup. A thorough analysis was done to better understand the Fabry-Perot interference in the Photo-elastic modulator (PEM) and the effect on the measurement method. When using a Photo-elastic modulator (PEM) in combination with a coherent light source, in addition to the modulation of the phase, Fabry-Perot interference in the PEM’s optical head induces large offsets in the 1w and 2w detector signals. A Jones matrix which describes both the phase and amplitude modulations simultaneously, was derived and used to find an expression for the detector signal for two different MO Kerr setups. The effect of the PEM tilt angle, polarizer angle, analyzer angle, and retardation, on the detector signal offsets show that offsets can be zeroed by adjusting PEM tilt angle, polarizer angle, and retardation. This strategy will allow one to avoid large offset drifts due to the small retardation, intensity, and beam direction fluctuations caused by lab temperature fluctuations. In addition, it will enable one to measure in the most sensitive range of the lock-in amplifiers further improving the signal to noise ratio of the setup.

Publications:

[1] Md. Abdul Ahad Talukder, Wilhelmus J. Geerts, “Jones matrix description of Fabry-Perot interference in a single axis photoelastic modulator and the consequences for the magnetooptical measurement method.”, accepted for publication in AIP Advances, August 2017.
[2] Md. Abdul Ahad Talukder, Wilhelmus J. Geerts, “Tilt angle dependence of the modulated interference effect in Photo-elastic Modulators”, AIP Advances, vol. 7, 056719 1-4, 2017; doi: 10.1063/1.4975999.
[3] Md. Abdul Ahad Talukder, Yubo Cui, Maclyn Compton, Luisa Scolfaro, Stefan Zollner, Wilhelmus J. Geerts, "FTIR Ellipsometry study on RF sputtered Permalloy-oxide Thin Films", MRS Advances 1, 49 (2016), pp. 3361-3366.

Presentations/Posters:

[4] Md Abdul Ahad Talukder, Wilhelmus J. Geerts, “Tilt angle dependence of the modulated interference effect in Photo-elastic Modulators”, poster presentation MMM conference October 2016, New Orleans.
[5] Md Abdul Ahad Talukder, Yubo Cui, Maclyn Compton, Wilhelmus Johannes Geerts, Luisa Scolfaro, Stefan Zollner, "FTIR Ellipsometry Study on RF Sputtered Permalloy-Oxide Thin Films", poster presentation, Symposium EP11 – Novel Materials for End-of-Roadmap Devices in Logic, Power and Memory, MRS Spring Meeting, March 28-April 1 2016, Phoenix, Arizona. ,br> [6] Md Abdul Ahad Talukder, Wilhelmus J. Geerts, Interference effects in Photo-elastic modulator when using highly coherent light, oral presentation at the Fall-2016 Joint meeting of the four corners and Texas Sections of the American Physical Society, Las Cruces, New Mexico.
[7] James Shook, Yubo Cui, Md Abdul Ahad Talukder, Tang Xi, Greg McClendon, Alex Zakhidov, Luisa Scolfaro, Wilhelmus Geerts, Sheet resistance measurements on a Fe-doped NiO ReRam Test Chip, oral presentation 2015 TSAPS-Fall meeting Baylor University, October 29-31, Texas.
[8] Yubo Cui, Md Abdul Ahad Talukder, Greg McClendon, Xi Tang, Wilhelmus Geerts. Iron Doped NiO Based Resistive RAM Test Chip, oral presentation 7th international research conference for graduate students, Texas State University, Nov. 17-18, 2015.
[9] Md Abdul Ahad Talukder, Yubo Cui, Wilhelmus J. Geerts, Study of the Crystal Properties of Iron Doped NiO using an X-ray Diffactormeter, oral presentation 7th international research conference for graduate students, Texas State University Nov. 17-18, 2015.