Magnetic behavior in an ordered Co nanorod array.

The magnetization reversal process of an ordered Co nanorod array is shown using the images obtained from successive in-field magnetic force microscope (MFM) measurements. The magnetization reversal model is discussed according to local and whole magnetization reversal properties measured by the polar magneto-optical Kerr effect (PMOKE) and an alternating gradient magnetometer (AGM), respectively. Additionally, the dipolar field was probed using in-field MFM measurements. By removing the effect of the dipolar field, an intrinsic switching field distribution (SFD) is shown in a map with a hexagonal array. A detailed study of the dipolar field in ordered nanorod arrays with various diameters and pitches was carried out by numerical calculations.