Magnetic field is a physical phenomena induced by the motive electric charges in their surrounding space. Magnetism of materials arises from two atomic sources: the spin and orbital motions of electrons. Therefore, the magnetic characteristics of a material may change as a function of alloying constitution. Magnetic field strength is the measure of the vector magnetic quantity that determines the ability of an electric current, or a magnetic body, to induce a magnetic field at a given point, denoted as H, measured in A/m (amperes per meter, SI electromagnetic unit system) or Oe (oersteds, CGS electromagnetic unit system). One unit of A/m is defined as the field strength value induced by an infinite long linear conductor bearing one unity ampere electric current that locates 1/(2π) meters away from the measured position. 1Oe=1/(4π)×103 A/m.