Tilted media in a perpendicular recording system for high areal density recording

Zou, Yongchao; Wang, J. P.; Hee, C. H.; Chong, Tow Chong

doi:10.1063/1.1565503

Cited by 63 publications

(40 citation statements)

References 13 publications

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“…It is known that the magnetization delay is a strong function of the initial angle of the magnets [21] and in tilted media, magnetic layers are engineered to have built-in initial angles to increase their switching speed [28]. In this paper, we define delay in terms of angular momentum transfer that is independent of the chosen initial angle as shown in FIG.…”

Section: Delay Definitionmentioning

confidence: 99%

Ultrafast Spin-Transfer-Torque Switching of Synthetic Ferrimagnets

et al. 2016

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The switching speed and the write current required for spin-transfer-torque reversal of spintronic devices such as magnetic tunnel junctions (MTJ) currently hinder their wide implementation into memory and logic devices. This problem is further exacerbated as the dimensions of MTJ nanostructures are scaled down to tens of nanometers in diameter, as higher magnetic anisotropy materials are required to meet thermal stability requirements that demand higher switching current densities. Here, we propose a simple solution to these issues based on synthetic ferrimagnet (SFM) structures. It is commonly assumed that to achieve a given switching delay, the current has to exceed the critical current by a certain factor and so a higher critical current implies a higher switching current. We show that this is not the case for SFM structures which can provide significantly reduced switching delay for a given current density, even though the critical current is increased. This non-intuitive result can be understood from the requirements of angular momentum conservation. We conclude that a 20 nm diameter MTJ incorporating the proposed SFM free layer structure can be switched in tens of picosecond time scales. This remarkable switching speed can be attained employing current perpendicular magnetic anisotropy materials with experimentally demonstrated exchange coupling strengths.

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Section: Delay Definitionmentioning

confidence: 99%

Ultrafast Spin-Transfer-Torque Switching of Synthetic Ferrimagnets

et al. 2016

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“…However, the design of a head capable of generating a uniform and tilted fi eld is challenging. In contrast, use of tilted media 16,17 is a possible way to solve the above problem. By adjusting the average anisotropy direction in the tilted media, θ can be tuned to the points where the sensitivity of the switching fi eld is near to its minimum.…”

mentioning

confidence: 99%

Magnetic multilayers on nanospheres

et al. 2005

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T hin-fi lm technology is widely implemented in numerous applications 1. Although fl at substrates are commonly used, we report on the advantages of using curved surfaces as a substrate. Th e curvature induces a lateral fi lm-thickness variation that allows alteration of the properties of the deposited material 2,3 . Based on this concept, a variety of implementations in materials science can be expected. As an example, a topographic pattern formed of spherical nanoparticles 4,5 is combined with magnetic multilayer fi lm deposition. Here we show that this combination leads to a new class of magnetic material with a unique combination of remarkable properties: Th e so-formed nanostructures are monodisperse, magnetically isolated, single-domain, and reveal a uniform magnetic anisotropy with an unexpected switching behaviour induced by their spherical shape. Furthermore, changing the deposition angle with respect to the particle ensemble allows tailoring of the orientation of the magnetic anisotropy, which results in tilted nanostructure material.

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“…In contrast, little work has been dedicated to the fast dynamics of hard media [3,6,7]. One reason may be the technical difficulty in obtaining the high amplitude fast rising field pulses needed to trigger precessional switching in such media.…”

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confidence: 99%