Recording physics of perpendicular recording with single layered medium and ring head

In this article, the recording physics of a ring head with a single layered perpendicular medium (Ring/SL) is studied and the results are compared with a single pole head with a double layered perpendicular medium (SPT/DL) by using various simulations and experiments. The Ring/SL has much lower effective medium coercivity than the SPT/DL due to the substantial longitudinal field component of ring head and the incoherent rotation mode of medium magnetizations. Furthermore, switching time of the Ring/SL is estimated as only 10%∼30% of the SPT/DL. In the Ring/SL, the head field gradient of 40 Oe/nm is enough for maximizing SNR. The Ring/SL shows very low noise characteristics especially at high linear density. The signal output of the Ring/SL is smaller than the SPT/DL, but it is large enough to be detected. Therefore, it can be concluded that the combination of single layered perpendicular medium and ring head is highly promising for ultrahigh density recording.