2014 Fall Physics Colloquium Series: Wilhelmus J. Geerts, Ph.D.

DateNovember 5, 2014
Time4:00 - 5:00 pm
LocationBaylor Sciences Building, Room E.125
Dr. Ir. Wilhelmus J. Geerts

Department of Physics

Texas State University San Marcos

Optical Properties of Permalloy Oxide Grown by RF Magnetron Sputtering

Permalloy (Ni80Fe20) is used in most magnetic recording heads. It can flip and retain its state easily; and, its magnetic properties do not depend on stress, a quantity that is difficult to control in integrated magnetic thin film heads. Whenever permalloy is oxidized, its magnetic properties change drastically. This was always seen as a defect in industry where companies would encapsulate Py-based sensors to prevent
oxidation. It was shown that a lateral spin valve, a sensor used in a magnetic reading
head, became much more sensitive whenever the Py layer was oxidized [1]. More recently in 2013, low turn on voltages for hematite water splitting cells were achieved by adding an amorphous NiFeOx layer [2]. So now Permalloy Oxide (PyO) is
suddenly a very interesting material to study for devices. But since PyO was always seen as a defect, there is little information published on just PyO. To understand how PyO can be used in devices to make them more efficient we need to understand the electronic properties of PyO itself. And, to be able to apply PyO thin films in
devices, we need measurement tools and methods to characterize the PyO, such as the thickness of a PyO layer. Film thicknesses are best measured by optical techniques, but one would need the optical properties of PyO to do so. I this
presentation I will present measurement results on PyO thin films made by RF magnetron sputtering. We will discuss their optical and electrical properties.

1. Goran Mihajlovic, Daniel K. Schreiber, Yuzi Liu, John E. Pearson, Samuel D. Bader,
Amanda K. Petford-Long, and Axel Hoffmann, Appl. Phys. Lett. 97, 112502 (2010).

2. Chun Du, Xiaogang Yang, Matthew T. Mayer, Henry Hoyt, Jin Xie, Gregory McMahon,
Gregory Bischoping, and Dunwei Wang, Angewandte Communications 52 Pages 12692-12695 (2013).

For more information, please contact:
Dr. Anzhong Wang 254-710-2276

PublisherDepartment of Physics
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