Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence of Dilute Ferromagnetism in Rare-Earth doped YAG   This work demonstrates strong coupling regime between an Erbium ion spin
ensemble and microwave Hybrid Cavity-Whispering Gallery Modes in a Yttrium
Aluminium Garnet dielectric crystal. Coupling strengths of $220$~MHz and mode
quality factors in excess of $10^6$ are demonstrated. Moreover, the magnetic
response of high-Q modes demonstrates behaviour which is unusual for
paramagnetic systems. This behaviour includes hysteresis and memory effects.
Such qualitative change of the system's magnetic field response is interpreted
as a phase transition of Rare Earth ion impurities. This phenomenon is similar
to the phenomenon of dilute ferromagnetism in semiconductors. The clear
temperature dependence of the phenomenon is demonstrated.

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The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph