In this work the interactions between neighboring superconducting thin film
and ferromagnetic structures, i.e. superconductor-ferromagnet hybrid systems, were
studied. A type-II superconducting thin film (Pb82Bi12), was deposited in close proximity
to various ferromagnetic structures. These magnetic structures include: (i)
alternating iron-brass shims of 275 mu m period, (ii) an array of 4 mu m wide Co stripes
with smaller period (9 mu m), (iii) a square array of 50nm diameter, high aspect ratio
(5-7) Ni rods with 250nm period. Measurements of critical transport current (IC),
resistance (RH(T)) and second critical field (HC2) are reported. A variety of novel effects
(enhancement of (IC) and (HC2), matching field effect, field compensation effect,
and large hysteresis) are also reported. Using measurements on thin superconducting
films atop a Co stripe array with a 9 mu m period, a superconductor-ferromagnet hybrid
device (a mechanical superconducting persistent switch) is proposed.
In addition, scanning Hall probe microscopy (SHPM) and other imaging techniques
were used to characterize the magnetic properties of the systems mentioned.
The SHPM was also used to acquire B-H and M-H curves. An additional sharp
magnetic needle and electromagnetic coil assembly intended for micromanipulation
of small magnetic particles and individual cells was also characterized.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2009-05-742 |
| Date | 2009 May 1900 |
| Creators | Ozmetin, Ali E. |
| Contributors | Naugle, Donald G. |
| Source Sets | Texas A and M University |
| Language | English |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | application/pdf |
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