Controlling multidomain states to enable sub-10-nm magnetic force microscopy

Abstract

The letter reports experimental data to demonstrate magnetic force microscopy (MFM) with sub-10-nm resolution under ambient conditions. To achieve this record high resolution, multidomain states in a nanomagnetic probe were controlled. Two demagnetized (multidomain) FePt (45/55) films sputtered on a silicon probe and separated by an 8 nm thick MgO layer were further annealed at temperature of 650 °C to trigger the high-anisotropy L10 phase. A field of above 2 T was applied to drive the probes into a saturated “single-domain” state. The multidomain probes were equivalently compared with state-of-the-art conventional MFM probes via comparative imaging of benchmark magnetic recording disks.

Spatial resolution and switching field of magnetic force microscope tip coated with FePd-alloy thin film

“…Therefore, realization of high H sw is required in addition to highresolution better than 10 nm for MFM observations of such ultra-high-density media. MFM tips with high H sw have been prepared by annealing tips coated with L1 0 ordered FePt-and CoPt-alloy films followed by focusedion-beam milling [6,7]. However, the resolution of commercially available MFM tip coated with L1 0 ordered film is limited at around 20 nm.…”

“…MFM tips are generally prepared by coating non-magnetic sharp tips with magnetic materials [1]- [7]. The tip shape and the magnetic property of coated material influence the spatial resolution and the switching field (H sw ) of MFM tip.…”

Switching fields of high-resolution magnetic force microscope tips coated with Co, Co75Pt10Cr15, Co75Pt25, and Co50Pt50films

“…MFM tips are generally prepared by coating non-magnetic sharp tips with magnetic films [1][2][3][4]. The tip shape and the magnetic property of coated film material influence the spatial resolution and the magnetic switching field (H sw ) of MFM tip.…”

“…High H sw tips have been prepared by using L1 0 ordered Co 50 Pt 50 [3], Fe 50 Pt 50 [4], and Fe 50 Pd 50 [5,6] alloys as coating magnetic materials. However in order to prepare L1 0 ordered films with high K u , it is necessary to employ high temperature processing around 600 °C, which causes irregular surface of coated film and decrease the MFM resolution [7].…”

Magnetic Force Microscope Tip with High Resolution and High Switching Field Prepared by Coating Si Tip with L11 Ordered CoPt-Alloy Film

“…Tip is a key component in an MFM system which determines the spatial resolution. MFM tips are generally prepared by coating non-magnetic sharp tips with magnetic films [1][2][3][4][5][6][7][8][9][10][11] . Future magnetic recording media of hard-disk-drives (HDDs) will employ magnetic materials with high uniaxial magnetocrystalline anisotropy energies (Ku) such as FePt and SmCo5, where the MFM tip will be exposed to a high magnetic field.…”