Transverse Field Effects of Al Concentration on Magnetic Properties of B2-FeAl Nanoparticle

Transverse field dependence of magnetic properties of the B2-FeAl nanoparticle (B2-FeAl-np) is investigated by using the effective field theory (or the Kaneyoshi theory) at H = 0 and H = 0.25. It is found that the magnetization and the Curie temperature of B2-FeAl-np decrease as the transverse field increases. A similar decrease in the magnetization and the Curie temperature of B2-FeAl is experimentally observed by Plazaola et al. with the increase (27.5%, 30%, 32.5% and 35%) of the Al content in B2-FeAl. These theoretical and experimental results revealed that the increase of the Al content in B2-FeAl-np causes an increase in the transverse field of B2-FeAl-np. Thus, the magnetization and the Curie temperature of B2-FeAl-np decrease. However, the ferromagnetic and antiferromagnetic spin splitting of paramagnetic Fe and Al atoms is obtained by a non-zero external magnetic field (H = 0.25) at T > T-C