Magnetic state control of ferromagnetic nanodots by magnetic force microscopy probe

Abstract

We present the magnetic state control of individual ferromagnetic nanodots under inhomogeneous magnetic field induced by the probe of magnetic force microscope ͑MFM͒. Arrays of submicron sized elliptical ferromagnetic Co and FeCr dots with different sizes and periods were fabricated to demonstrate addressable manipulation of magnetization. MFM observations show the magnetization reversal and processes of local remagnetization of individual ferromagnetic nanodots subjected to magnetic change. Computer simulation of magnetization processes under inhomogeneous magnetic field induced by MFM probe was performed on the base of Landau-Lifshitz-Gilbert equation for magnetization.

Magnetic force microscope tip-induced remagnetization of CoPt nanodisks with perpendicular anisotropy

“…Previously we also reported the influence of the MFM probe inhomogeneous magnetic field on the in-plane remagnetization processes in elliptical ferromagnetic nanodisks. [20][21][22] We showed experimentally and by micromagnetic simulations that nonsymmetrical scanning of the inhomogenous tip field over the particle allows one to induce transitions between uniform states with different orientations and between uniform and vortex states. In the present paper we report on the processes involved in tipinduced remagnetization in circular CoPt nanodisks with perpendicular magnetic anisotropy.…”

Magnetic interactions in 2D and 3D arrays

“…For larger islands, a larger fraction of the tip is active. Besides this, the effective write field of the tip depends on the probe motion [Chang et al, 2006;Kleiber et al, 1998;Zhu et al, 2002] and the switching mechanism of the islands . For instance, Mironov et al experienced this in their demonstration of probe recording on bit patterned media with perpendicular anisotropy .…”

“…Most impressively, soft-magnetic elliptical islands could be manipulated into uniform and vortex states by precise control of the scanning motion of the tip [Chang et al, 2006]. Typically standard/commercial MFM tips are employed, which have a magnetic coating (e.g.…”

“…Thickly coated, high moment tips may directly write the sample solely by their strong stray fields [Amos et al, 2012;Kong et al, 1997]. In read back, such tips are employed strictly in noncontact mode to avoid unwanted writing; intentional writing is attained by letting the tip approach the sample selectively [Chang et al, 2006;Hassel et al, 2009;Zhu et al, 2002]. Ideally however, the in-contact field of the tip is smaller than the switching fields of the imaged elements, as this allows for read back in tapping/liftmode without the tip distorting the sample.…”

“…MFM tips were used to write wires [Hassel et al, 2009], pillars [Jaafar et al, 2009], as well as thin-film recording media [Manalis et al, 1995] and islands with in-plane [Chang et al, 2006;Kleiber et al, 1998;Zhu et al, 2002] and perpendicular [Amos et al, 2012; anisotropy. Most impressively, soft-magnetic elliptical islands could be manipulated into uniform and vortex states by precise control of the scanning motion of the tip [Chang et al, 2006].…”