Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Anisotropic phase diagram of the frustrated spin dimer compound Ba3Mn2O8   Heat capacity and magnetic torque measurements are used to probe the
anisotropic temperature-field phase diagram of the frustrated spin dimer
compound Ba3Mn2O8 in the field range from 0T to 18T. For fields oriented along
the c axis a single magnetically ordered phase is found in this field range,
whereas for fields oriented along the a axis two distinct phases are observed.
The present measurements reveal a surprising non-monotonic evolution of the
phase diagram as the magnetic field is rotated in the [001]-[100] plane. The
angle dependence of the critical field (Hc1) that marks the closing of the spin
gap can be quantitatively accounted for using a minimal spin Hamiltonian
comprising superexchange between nearest and next nearest Mn ions, the Zeeman
energy and single ion anisotropy. This Hamiltonian also predicts a
non-monotonic evolution of the transition between the two ordered states as the
field is rotated in the a-c plane. However, the observed effect is found to be
significantly larger in magnitude, implying that either this minimal spin
Hamiltonian is incomplete or that the magnetically ordered states have a
slightly different structure than previously proposed.

22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex