Switching Phase Diagram of Two Frequencies MAMR for ECC Media

A two-particle model is utilized to study the switching phase diagram of ECC media in the microwave-assisted magnetic recording, by applying an in-plane AC magnetic field for microwave and a DC magnetic field for write head field. An interesting result is found that, by introducing two mixed linearly polarized AC fields when the ratio of frequencies f₂/f₁ is in a certain range, the minimum switching DC field can be almost zero when H_ac is 20% of H_k1 of hard magnetic layer. This phase diagram is also checked by a 3D micromagnetic model of ECC media with polycrystalline structure included; with two linearly polarized H_ac applied, the coercivity H_c can be reduced to almost zero when H_ac = 2.0 H_k1, and H_c still decreases from 10.5 kOe to 7.7 kOe when H_ac = 0.02 H_k1.