Abstract
In recent years, due to the rapid development of spintronic devices such as hard drive heads, magnetic random access memory, etc., research of magnetic materials become more important. In nanoscaled some of materials properties is different. In this thesis, we study the relationship between thermal conductivity and magnetic field and that between temperature of nickel nanowires. Nano-scaled magnetic structures are fabricated by using e-beam lithography and e-beam evaporation system. The thermal conductivity of the structures is measured by electrical resistance thermometry on self-heated structure. The thermal conductivity of the structures decrease with magnetic field but the electron conductivity are all the same. The calculated Lorenz numbers (from the thermal and electrical conductivity data) of nickel nanowire decrease with magnetic field. We found a way to change Lorenz number and broken the Wiedemann-Franz law.