Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin diffusion and magnetoresistance in
  ferromagnet/topological-insulator junctions   We study spin and charge diffusion in
metallic-ferromagnet/topological-insulator junctions. The coupled diffusion
equations are derived perturbatively with respect to the strength of the
interlayer tunneling. We calculate spin accumulation in the ferromagnet and
junction magnetoresistance associated with a current bias along the interface.

27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph