Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic Penetration Depth in Unconventional Superconductors   This topical review summarizes various features of magnetic penetration depth
in unconventional superconductors. Precise measurements of the penetration
depth as a function of temperature, magnetic field and crystal orientation can
provide detailed information about the pairing state. Examples are given of
unconventional pairing in hole- and electron-doped cuprates, organic and heavy
fermion superconductors. The ability to apply an external magnetic field adds a
new dimension to penetration depth measurements. We discuss how field dependent
measurements can be used to study surface Andreev bound states, nonlinear
Meissner effects, magnetic impurities, magnetic ordering, proximity effects and
vortex motion. We also discuss how penetration depth measurements as a function
of orientation can be used to explore superconductors with more than one gap
and with anisotropic gaps. Details relevant to the analysis of penetration
depth data in anisotropic samples are also discussed.

13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol