We investigated the magnetic phase diagram of single crystals of SrNdFeO4 by measuring the magnetic properties, the specific heat and the dielectric permittivity. The system has two magnetically active ions, Fe3+ and Nd3+. The Fe3+ spins are antiferromagnetically ordered below 360 K with the moments lying in the ab-plane, and undergo a reorientation transition at about 35-37 K to an antiferromagnetic order with the moments along the c-axis. A short-range, antiferromagnetic ordering of Nd3+ along the c-axis was attributed to the reorientation of Fe3+ followed by a long-range ordering at lower temperature [S. Oyama {\it et al.} J. Phys.: Condens. Matter. {\bf 16}, 1823 (2004)]. At low temperatures and magnetic fields above 8 T, the Nd3+ moments are completely spin-polarized. The dielectric permittivity also shows anomalies associated with spin configuration changes, indicating that this compound has considerable coupling between spin and lattice. A possible magnetic structure is proposed to explain the results.
@article{arxiv.1206.4597,
title = {Magnetic transitions and magnetodielectric effect in the antiferromagnet SrNdFeO$_4$},
author = {J. M. Hwang and E. S. Choi and H. D. Zhou and Y. Xin and J. Lu and P. Schlottmann},
journal= {arXiv preprint arXiv:1206.4597},
year = {2015}
}