Books:

1. Jiles, David. Introduction to Magnetism and Magnetic Materials. London: Chapman & Hall, 1998.
2. Solid State Physics - S. O. Pillai, New Age International Publishers, 6th (e) revised.

Webliography:

http://en.wikipedia.org/wiki/Barkhausen_effect
http://www.physics.ucla.edu/demoweb/demomanual/electricity_and_magnetism/magnetostatics/barkhausen_effect.html
http://www.magnet.fsu.edu/education/tutorials/java/barkhausen/index.html

Video References:
 

http://www.youtube.com/watch?v=iWdbRX5Nyg4
http://www.youtube.com/watch?v=8-0UytwADgo