Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: HAMR Thermal Reliability via Inverse Electromagnetic Design   Heat-Assisted Magnetic Recording (HAMR) has promise to allow for data writing
in hard disks of beyond 1 Tb/in2 areal density, by temporarily heating the area
of a single datum to its Curie temperature while simultaneously applying a
magnetic field from a conventional electromagnet. However, the metallic optical
antenna or near-field transducer (NFT) used to apply the nano-scale heating to
the media may self-heat by several hundreds of degrees. With the NFT reaching
such extreme temperatures, demonstrations of HAMR technology observe write-head
lifetimes that are orders of magnitude less than that required for commercial
product. Hence, thermal reliability of the NFT is of upmost importance. In this
paper, we first derive fundamental limits on the self-heating of the NFT to
drive design choices for low temperature operation. Next, we employ Inverse
Electromagnetic Design software, which provides deterministic gradient-based
optimization of electromagnetic structures with thousands of degrees of freedom
using the adjoint method. The Inverse Design software solves for unintuitive
solutions to Maxwells equations, and we present computationally generated
structures for HAMR write-heads that offer a 40 percent or 170 C reduction in
NFT self-heating compared to typical industry designs.

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The categories of this paper are: q-bio
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The categories of this paper are: mtrl-th
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The categories of this paper are: stat
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The categories of this paper are: adap-org
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The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-lat
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The categories of this paper are: nlin
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The categories of this paper are: quant-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: q-alg
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The categories of this paper are: hep-th