Method of fabricating an object with a thin wall having a precisely shaped slit

A method is described for making a structure with a cavity and a thin wall with a precisely shaped slit. An object with a cavity having two openings, one of which is to be closed by a thin wall with a slit, is placed on the surface of a fixture. The fixture surface has a slot conforming to the size and shape of the slit to be formed in the thin wall

Angular dependence of domain wall resistivity in artificial magnetic domain structures

We exploit the ability to precisely control the magnetic domain structure of perpendicularly magnetized Pt/Co/Pt trilayers to fabricate artificial domain wall arrays and study their transport properties. The scaling behaviour of this model system confirms the intrinsic domain wall origin of the magnetoresistance, and systematic studies using domains patterned at various angles to the current flow are excellently described by an angular-dependent resistivity tensor containing perpendicular and parallel domain wall resistivities. We find that the latter are fully consistent with Levy-Zhang theory, which allows us to estimate the ratio of minority to majority spin carrier resistivities, rho-down/rho-up~5.5, in good agreement with thin film band structure calculations.Comment: 14 pages, 3 figure

Bounce in Valley: Study of the extended structures from thick-wall to thin-wall vacuum bubbles

The valley structure associated with quantum meta-stability is examined. It is defined by the new valley equation, which enables consistent evaluation of the imaginary-time path-integral. We study the structure of this new valley equation and solve these equations numerically. The valley is shown to contain the bounce solution, as well as other bubble structures. We find that even when the bubble solution has thick wall, the outer region of the valley is made of large-radius, thin-wall bubble, which interior is occupied by the true-vacuum. Smaller size bubbles, which contribute to decay at higher energies, are also identified.Comment: 9 pages + 4 figures, KUCP-006

Origin and tailoring of the antiferromagnetic domain structure in α\alpha-Fe2_2O3_3 thin films unraveled by statistical analysis of dichroic spectro-microscopy (X-PEEM) images

The magnetic microstructure and domain wall distribution of antiferromagnetic $\alpha$-Fe$_2$O$_3$ epitaxial layers is determined by statistical image analyses. Using dichroic spectro-microscopy images, we demonstrate that the domain structure is statistically invariant with thickness and that the antiferromagnetic domain structure of the thin films is inherited from the ferrimagnetic precursor layer one, even after complete transformation into antiferromagnetic $\alpha$-Fe$_2$O$_3$. We show that modifying the magnetic domain structure of the precursor layer is a genuine way to tune the magnetic domain structure and domain walls of the antiferromagnetic layers

Uniqueness of one-dimensional N\'eel wall profiles

We study the domain wall structure in thin uniaxial ferromagnetic films in the presence of an in-plane applied external field in the direction normal to the easy axis. Using the reduced one-dimensional thin film micromagnetic model, we analyze the critical points of the obtained non-local variational problem. We prove that the minimizer of the one-dimensional energy functional in the form of the N\'eel wall is the unique (up to translations) critical point of the energy among all monotone profiles with the same limiting behavior at infinity. Thus, we establish uniqueness of the one-dimensional monotone N\'eel wall profile in the considered setting. We also obtain some uniform estimates for general one-dimensional domain wall profiles.Comment: 18 page

Magnetic domain-wall motion by propagating spin waves

We found by micromagnetic simulations that the motion of a transverse wall (TW) type domain wall in magnetic thin-film nanostripes can be manipulated via interaction with spin waves (SWs) propagating through the TW. The velocity of the TW motion can be controlled by changes of the frequency and amplitude of the propagating SWs. Moreover, the TW motion is efficiently driven by specific SW frequencies that coincide with the resonant frequencies of the local modes existing inside the TW structure. The use of propagating SWs, whose frequencies are tuned to those of the intrinsic TW modes, is an alternative approach for controlling TW motion in nanostripes

Domain Walls and Metastable Vacua in Hot Orientifold Field Theories

We consider "Orientifold field theories", namely SU(N) gauge theories with Dirac fermions in the two-index representation at high temperature. When N is even these theories exhibit a spontaneously broken Z2 centre symmetry. We study aspects of the domain wall that interpolates between the two vacua of the theory. In particular we calculate its tension to two-loop order. We compare its tension to the corresponding domain wall in a SU(N) gauge theory with adjoint fermions and find an agreement at large-N, as expected from planar equivalence between the two theories. Moreover, we provide a non-perturbative proof for the coincidence of the tensions at large-N. We also discuss the vacuum structure of the theory when the fermion is given a large mass and argue that there exist N-2 metastable vacua. We calculate the lifetime of those vacua in the thin wall approximation.Comment: 29 pages, 4 figures. v2: minor changes in the introduction section. to appear in JHE