Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin order on pyrochlore lattices studied by the Self-Consistent Cluster
  Approach   In this paper we present a study of magnetic order of quantum Heisenberg
spins on pyrochlore type lattices: a lattice of corner sharing tetrahedra. We
use the Cluster Variation Approximation with the tetrahedron as basic cluster.
We find that in case of anti-ferromagnetic nearest--neighbour exchange there is
no long--range spin order at any finite temperature for any spin s. For
ferromagnetic exchange and s=1/2 the spin system remains in a non-magnetic
phase for all temperatures, while for s > 1/2 there is a finite order
temperature. We derive the ground state phase diagram as a function of exchange
anisotropy and tetragonal anisotropy and find regions of re--entrant behaviour.
Magnetic fields can induce one or more magnetic transitions. Schottky--like
anomalies appear in the specific heat, with on top signs of re--entrant
behaviour. The limits of this Cluster Variation Approximations are discussed.

35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph