First and foremost I offer my sincerest gratitude to my supervisor, Dr Mike Thomas, who has supported me thoughout my thesis with his patience and knowledge whilst allowing me the room to work in my own way. I attribute the level of my Masters degree to his encouragement and effort and without him this thesis, too, would not have been completed or written. One simply could not wish for a better or friendlier supervisor.

In the various laboratories and workshops I have been aided for many years in running the equipment by Keith Williams, a fine technician who kept me in sample holders and liquid helium against all odds. The smooth running of the Mössbauer laboratory is much more a testament to his efforts than my own. Simon Case and Gaby Milford helped tutor me in the more esoteric methods necessary to run Mössbauer spectrometers and how to analyse the data from them. Dr Jon Goff gave useful guidance in the use of the SQUID magnetometer along with Pascale Deen, and her ingenious sample holder construction. As well as keeping me stocked with general supplies, Peter Davenport has also inadvertently, and without fail, provided something much greater in all the years I've known him: a friendly smile and a hello every time we met.

Drs Ward and Wells have provided me with all of the Laves Phase MBE samples covered in this thesis as well as many others, with consistent quality. Professor Bowden has offered much advice and insight throughout my work on Laves Phase systems. Drs F. Schedin, P. Morrel and G. Thornton provided me with the magnetite thin films I studied.

In my daily work I have been blessed with a friendly and cheerful group of fellow students. Pascale Deen, as well as SQUID information, has provided good arguments about Physics theory and helped me regain some sort of fitness: healthy body, healthy mind. Adina Toader often made sure none of us starved and Simon Lee made sure none of us went thirsty (or sober). Tarek (Taz) Nouar kept us entertained with his huge repertoire of anecdotes and stories. Mark Gallagher amused us with his dry wit and a great no-nonsense Christmas shindig (and did a good job of trying to kill me with snakebite and black). Stuart Medway was a good companion on an otherwise exhausting and disappointing experiment in Grenoble and although he did once explain the difference between League and Union rugby I must confess to have forgotten every word since. Matt Ball has had the good grace to pester me much less than average with computer questions and pulls a good pint in the Cambridge. Jonathan Pearce helped me get on the road to LATEX and provided an experienced ear for my doubts about writing a thesis. Peter Normile has fascinated me with his ability to break computer systems but has also given me detailed discussions on physics theory and some good laughs. In many ways I have learnt much from and because of him! Angela Beesely has impressed me with her willingness to learn how to use both the computer systems I set up and the finer points of running the Mössbauer lab, which I now consider to be in her capable hands. She also kept me on my theoretical toes with her Mössbauer questions.

Beyond Physics (which sometimes seemed to be nothing more than a distant dream) Andrew Herring has been a companiable housemate for many years as well as a colleague and possesses the greatest quality in a housemate: not driving me up the wall too often! Simon Lee has been an invaluable help in taking over the computer systems from me and sometimes managed to counter my introversion with the occasional sneaky one up the Cambridge (this being an approximation that only holds for large values of `one'). His willingness to help people and make sure everyone has a good time is only matched by his willingness to bare his behind at all and sundry. Thanks also go to the other (million or so) residents at 8, Church Road, for living without their front room for a month. Gillian Howden has brightened many a dull lunchtime.

Kira Brown, as well as essentially teaching me everything I know about unix, has often had to bear the brunt of my frustration and rages against the world and recalcitrant spectrometers with equanimity and friendship. She also (eventually!) sourced me a quality workstation which much of the work has been done on. I am also indebted to the many countless contributors to the ``Open Source'' programming community for providing the numerous tools and systems I have used to produce both my results and this thesis. The entirety of my thesis has been completed using such technologies and I consider it to have been an enormous benefit. Thanks chaps, keep up the good work.

The Department of Physics has provided the support and equipment I have needed to produce and complete my thesis and the EPSRC has funded my studies.

Finally, I thank my parents for supporting me throughout all my studies at University, moving my vast collections of ``stuff'' across most of Liverpool and for providing a home in which to complete my writing up.

Dr John Bland, 15/03/2003