What are some good beginner level books to understand spintronics. I am looking for some sources in which basic mathematics of spintronics is properly explained.
You should start with books on solid state physics, obviously. Beginner level material is "Kittel" or "Ashcroft/Mermin". You may continue with mathematically more involved books as, for instance, Bruus/Flensberg to understand the modern solid state physics notation. There some basic spintronics phenomena are allready mentioned (Kondo effect and Luttinger Liquid). At some point you should be able to understand the following: Spintronics: Fundamentals and applications