Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Internal spin resistance of spin batteries   For spin batteries we introduce the concept of internal spin resistance which
quantifies the amount of backflow from the load to the battery. It allows to
relate through a Thevenin-Norton relation, spin current sources to spin
accumulation sources. The value of the internal spin resistance is derived
explicitly for several spin batteries based on spin injection, ferromagnetic
resonance or spin Hall effect.

6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
19
The categories of this paper are: eess