Spin, charge, and orbital order in Mn2OBO3

Abstract

The magnetic ordering in Mn2OBO3 has been determined from neutron diffraction and magnetization measurements. Long range antiferromagnetic order occurs below TN=26 K, other apparent magnetic transitions are due to secondary phases. The magnetic order has a (1/201/2) propagation vector and the antiferromagnetic spin arrangement has been refined. The low ordering temperature and ordered moment (1.0 μB) at the Mn3+ sites evidence magnetic frustration arising from the charge and orbital ordered arrangement of Mn2+ and Jahn-Teller Mn3+ states. This is supported by a qualitative assessment of the Mn-O-Mn superexchange interactions.