The Bloch point in uniaxial ferromagnets as a quantum mechanical object

Abstract

Quantum effects such as tunneling through pinning barrier of the Bloch Point and over-barrier reflection from the defect potential of one have been investigated in ferromagnets with uniaxial strong magnetic anisotropy. It is found that these phenomena can be appeared only in subhelium temperature range.

A general formalism for the determination of the effective mass of the nanoscale structural inhomogeneities of the domain wall in uniaxial ferromagnets

“…This approach presents significant difficulties [ 4 - 7 ], and it would be laudable to build a simpler theoretical formalism for finding m L,BP in the DW of different domain configurations. Another difficulty with the previous formalism is related to the dependence of the BL and BP parameters of the quantum effects, which take place for these magnetic structures in the subhelium temperature range, on their effective mass expressions [ 8 , 9 ]. This aspect is especially important for spintronics materials such as cylindrical nanowires and nanostripes in which is the presence of structures similar to BLs and BPs [ 10 - 13 ].…”

Quantum Oscillations of the Nanoscale Structural Inhomogeneities of the Domain Wall in Magnetic Bubble

“…For small displacements of the Bloch point 2 z BP / h < < 1 , this formula gives . Taking into account the obtained result, as well as the expression for the energy of interaction between BP and magnetic field [ 8 ] that cancels the energetic equivalence of the zones of vertical BL separated by the BP, we determine the BP frequency of harmonic oscillations: …”

“…The results of these researches determine the prospects of using the vertical BL and BP as hardware components in the microelectronics [ 3 ]. The further development of the BL and BP application is related to the investigation of their quantum properties that occur at low temperatures [ 4 – 8 ].…”

Magnetic Nanowires and Nanotubes

“…It is not clear whether this is an intrinsic physics associated with the BP, or an artefact due to the difficulty to model BPs in micromagnetism, despite the emergence of multiscale codes (Lebecki et al 2012, Andreas et al 2014, Lebecki and Nowak 2014, Evans et al 2014. The pinning of the BP on a micromagnetic or atomic mesh is indeed a recognized effect, leading to a threshold field for wall motion (Piao et al 2013, Kim and Tchernyshyov 2013, Shevchenko and Barabash 2014, Hertel and Andreas 2015, and modulation of speed associated with the mesh spatial period (Thiaville et al 2003, Usov et al 2007), the latter author reporting a decrease of these effects for increasing wire diameter.…”