Exchange bias has been studied extensively for over half of a century but
most of the researchhas been carried out in the configuration called parallel
exchange bias. In this configuration,the cooling field and the measurement
field are applied in the plane. Beside parallel exchange bias, there has been
very little work carried out in the perpendicular configuration with the cooling
field and the measurement field along the filmnormal. Perpendicular
exchange bias is recently of renewed interest becauseit is relevant in the
quest for a better understanding of the microscopic originof the exchange
bias phenomenon and itmight lead to wide applications inmagnetic sensors,
perpendicular recording media, perpendicular magnetic read heads and also
magnetic randomaccess memories (MRAMs).
In this thesis, the studies on perpendicular exchange bias in [MnPd/Co]10
multilayers are reported for the first time. Since the objective of the present
thesis is to study the perpendicular exchange bias mechanism,the approach is
to investigate both the parallel and perpendicular exchange biases. Besides,
perpendicular anisotropy of the samples atlow and roomtemperatures is also
investigated due to its important contribution to the effect.
The present thesis consists of 4 chapters.
Chapter 1is to give an overview on exchange bias in both theoretical and
experimental research; and also previous studies on perpendicular exchange
bias.
Chapter 2focuses on the sample preparation and experimental
techniques. Somedescriptions on the apparatuses and measurements thatwere
used in the present thesis are introduced.
Chapter 3represents the experimental results. The aim and configurations
of measurements and also sample processing procedures are given.
Chapter 4is to discuss the results ofcrystallographic and magnetic
properties of [MnPd/Co]10multilayers. The behavior of exchange bias in both
the parallel and perpendicular directions will be summarized. After that, based
on that result and the magnetic anisotropy behavior of the samples, we try to
give a phenomenological picture to explain the perpendicular exchange bias
coupling mechanism.
Finally, conclusions and further direction as well as the list of references
are given at the end of the thesis.
