Low-temperature magnetic phase transitions of the geometrically frustratedisosceles triangular Ising antiferromagnet CoNb2O6 - art. no. 024415

Low-temperature magnetic phase transitions of the geometrically frustrated isosceles triangular Ising antiferromagnet CoNb2O6 have been investigated b y means of neutron diffraction down to T = 0.2 K under applied fields up to H-parallel toc,=4.4 kOe. Below T similar to0.6K, the relaxation time of th e system becomes extremely long compared with our observation time, being r esponsible for all the anomalous low-temperature magnetic properties observ ed in the bulk measurements [T. Hanawa et nl., J. Phys. Sec. Jpn. 63, 2706 (1994)]. In addition to confirmation of the triple point where the antiferr omagnetic, field-induced ferrimagnetic, and incommensurate phases meet toge ther in the H-parallel toc-T magnetic phase diagram, we also found various ordered phases that are field induced between the ferrimagnetic and saturat ed paramagnetic phases.