Phase diagram for magnetic nano-rings

Beleggia, Marco; Lau, June W.; Schofield, M. A.; Zhu, Yimei; Tandon, S.; Graef, Marc De

doi:10.1016/j.jmmm.2005.06.024

Cited by 51 publications

(38 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hence, demagnetization factors are relevant in general to study the magnetic response of isolated and interacting elements under various external parameters, especially an externally applied field. Magnetic phase diagrams [8][9][10][11][12][13] may also be compiled to provide insight in the expected magnetic ground state as a function of shape and geometry. When non-uniform states are involved, the demagnetization factors may represent the basis for a perturbation analysis of the energetics [14].…”

Section: Introductionmentioning

confidence: 99%

Demagnetization factors for cylindrical shells and related shapes

Beleggia

Vokoun

Graef

2009

Journal of Magnetism and Magnetic Materials

Self Cite

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Demagnetization factors for cylindrical shells and related shapes

Beleggia

Vokoun

Graef

2009

Journal of Magnetism and Magnetic Materials

Self Cite

View full text Add to dashboard Cite

“…A theoretical phase boundary separating the expected occurrence of in-plane and vortex states in circular rings as we vary the shape parameters (σ,τ) was derived in [10]. However, the simplified considerations therein turned out to be a rough underestimate of a realistic curve, such as one obtained by micromagnetic simulations.…”

Section: The Magnetic Phase Diagrammentioning

confidence: 99%

Occurrence of the vortex state for magnetic phase plates

Hari

Beleggia

Brydson

2010

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

Occurrence of the vortex state for magnetic phase plates Abstract. Tunable magnetic phase plates may be realized as nanorings magnetized in the vortex state, where tunability would be granted by the temperature dependence of the saturation magnetization. Here, we study the statistical occurrence of the magnetic vortex state in circular and pentagonal rings within their magnetic phase diagram. We outline the useful operational range of parameters that may be utilized in practice. IntroductionIn addition to a large number of promising applications in the field of magnetic memories [1] and spintronics [2], nanorings may be utilized as magnetic phase plates in electron microscopy to achieve Zernike-type phase contrast [3,4]. In fact, thanks to the Aharonov-Bohm effect experienced by the electrons traveling through a nanoring in the vortex state, a phase shift is induced between the transmitted and scattered beams. The main benefit is visible in-focus contrast associated with weak (or strong) phase objects such as biological samples [5]. Furthermore, it was hinted in [6] that employing Zernike mode may also result in a substantial decrease of the electron dose necessary to image single atoms or molecules, so that imaging radiation sensitive materials becomes more practical. Aiming at the development of magnetic phase plates we focus here on the stability region of the vortex state in rings within a suitable parameter space. This is a necessary preliminary step to ascertain the range of dimensions and shapes that are compatible with an operational phase plate. Furthermore, we analyze with micromagnetic simulations the statistics of obtaining a vortex from a random initial configuration, and how the statistics varies with shape and size. This is useful to select the appropriate parameters that results in more frequent vortex states and, hence, reliable operability.

show abstract

“…In fact, the demagnetization factor hNi zz for a ring having the specified parameters (R 2 ¼ 15 nm; R 1 ¼ 10 nm; t ¼ 4 nm) is 0.553, which is larger than 1 3 : This implies that the magnetization will most likely be confined in the ring plane (see Ref. [16]). A 2D inplane search for a minimum reveals thatm 1 forms an angle of 36:5 with the x-axis, andm 2 is at 7:80 with the z-axis.…”

Section: Numerical Approachmentioning

confidence: 99%