Magnetic behaviors of two spheres which contact each other with an area

In the chain of spheres model proposed by Jacobs and Bean, spheres contact each other at a point. In order to see the change of the magnetic behaviors of the chain of spheres when spheres begin to contact each other with an area, we consider the chain of two spheres. Critical field Hcri for the irreversible rotation of the magnetization and coercive force Hc by both the parallel rotation and fanning mechanisms are calculated as a function of the contact area. Uniaxial magnetic anisotropy constant Ku by the parallel rotation mechanism is also calculated as a function of the contact area. Ku, Hcri, and Hc are found to increase, reach a maximum value, and decrease with an increase in contact area. The maximum values of Ku and Hcri by the parallel rotation mechanism are found to be 30% larger than the values of Ku and Hcri for the point contact. The maximum value of Hcri by the fanning mechanism is found to be 15% larger than the value of Hcri for the point contact.