Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic and electric properties of CaMn7O12 based multiferroic
  compounds: effect of electron doping   The mixed-valent multiferroic compound CaMn7O12 is studied for its magnetic
and electric properties. The compound undergoes magnetic ordering below 90 K
with a helimagnetic structure followed by a low temperature magnetic anomaly
observed around 43 K. The present study shows that the magnetic anomaly at 43 K
is associated with thermal hysteresis indicating first order nature of the
transition. The compound also shows field-cooled magnetic memory and relaxation
below 43 K, although no zero-field-cooled memory is present. Clear magnetic
hysteresis loop is present in the magnetization versus field measurements
signifying the presence of some ferromagnetic clusters in the system. We doped
trivalent La at the cite of divalent Ca expecting to enhance the fraction of
Mn$^{3+}$ ions. The La doped samples show reduced magnetization, although the
temperatures associated with the magnetic anomalies remain almost unaltered.
Interestingly, the spontaneous electrical polarization below 90 K increases
drastically on La substitution. We propose that the ground state of the pure as
well as the La doped compositions contain isolated superparamagnetic like
clusters, which can give rise to metastability in the form of field-cooled
memory and relaxation. The ground state is not certainly spin glass type as it
is evident from the absence of zero-field-cooled memory and frequency shift in
the ac suceptibility measurements.

9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th