Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pressure-induced giant enhancement of magnetocaloric effects in
  MnNiSi-based systems   A remarkable decrease of the structural transition temperature of MnNiSi from
1200 K to <300 K by chemically alloying it with MnFeGe results in a coupling of
the magnetic and structural transitions, leading to a large magnetocaloric
effect near room temperature. It was found that the magnetostructural
transition is highly sensitive to external (hydrostatic) pressure: relatively
low hydrostatic pressures (~2.4 kbar) lead to an extraordinary enhancement of
the isothermal entropy change from $-$\Delta $S$ = 44 to 89 J/kg K at ambient
(atmospheric) and 2.4 kbar applied pressures, respectively, for a field change
of \Delta $H$ = 5 T. This giant entropy change is associated with a large
relative volume change of about 7% induced by 2.4 kbar applied pressure during
the magnetostructural transition. The pressure-enhanced magnetocaloric effects
are accompanied by a shift in transition temperature, an effect that may be
exploited to tune the transition to the required working temperature, and
thereby eliminate the need for a given material to possess a large
magnetocaloric effect (i.e., entropy change) over a wide temperature range.
Furthermore, this material also possesses negligible hysteresis losses.

2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat