Study of magnetic properties of magnetic force microscopy probes using micronscale current rings

Abstract

Metal rings with inner diameters of 1 and 5 m, fabricated using electron-beam lithography, were used to calibrate magnetic force microscopy ͑MFM͒. A MFM tip's effective magnetic charge, q, and effective magnetic moment along the tip long axis, m z , can be determined by the current flowing in the ring. The magnetic moments in the directions transverse to the tip's long axis were estimated by a straight current wire. It was found that for a silicon tip coated with 65 nm thick cobalt on the side, q ϭ 2.8 ϫ 10 Ϫ6 emu/cm, m z ϭ 3.8 ϫ 10 Ϫ9 emu, and m x ϭ m y ϭ 10 Ϫ13 emu, which are negligible compared with m z. Furthermore, the tip's sensitivity to the second derivative of the magnetic field was found to be about 0.1 Oe/nm 2 .

Towards quantitative magnetic force microscopy: theory and experiment

“…We included a fit which corresponds to the expected signal of a dipole within the pseudopole model (green curve). Neglecting the modulation amplitude and the vdW interaction, the expected frequency shift can be calculated by starting with equation (2) and following the same ideas that led to equation (5), resulting in…”

“…Apart from this more theoretical approach, attempts have been made to calibrate the magnetic sensors experimentally. These attempts rest on the Biot-Savart law, creating a well-defined magnetic field by an electric current through a well-defined micro-machined arrangement of wires [5][6][7][8]. Kebe and Carl [9] presented a similar analysis employing parallel wires.…”

Stray fields of domains in permalloy microstructures—Measurements and simulations

“…It is now commonly accepted that either the dipole or the monopole contribution can be used to model the MFM tip. [25][26][27] For the present calculations, the MFM tip is considered a magnetic point dipole. 28 As long as the tip-sample distance, i.e., the lift-scan height, is significantly larger than the cell size of the dipole array, this is a valid approximation.…”

Resolution of Magnetic Force Microscope with Metal-Capped Carbon Nanotube Tips

“…[8][9][10] The result shows that the Fe 3 C-capped nanotube has the dipole and monopole moments of 1.9 10 -12 emu and 2.6 10 -8 emu/cm, respectively. 2) These values are four and eight times larger than those of the Ni 3 C-capped one, respectively when they have the same volume.…”