Ferromagnetic ordering in a new nickel polyborate NiB12O14(OH)10.
A new nickel polyborate, NiB12O14(OH)10 was synthesized using boric acid as a flux. This material has two-dimensional borate layers with a quasi-square lattice of Ni2+. The Ni2+ ions locate in the plane of the two-dimensional layer, bridged through BnO(n+1) chains in the plane and connected with the three-membered ring borate groups out of the plane. The dc and ac magnetic susceptibility, magnetization and specific heat measurements show that this material undergoes a weak ferromagnetic phase transition at Tc = 5.8 K. At T < Tc, a metamagnetic phase transition is observed at about 5 T, associated by a spin-flop, suggesting the ferromagnetic ordering is induced by an antiferromagnetic interaction. A broad maximum in the ac susceptibility at TM = 23-24 K indicates an intermediate short-range ordering.
Physics Department, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan. jujing@ldp.phys.tohoku.ac.jp
Jing
J
Ju
Jun
J
Sasaki
Tao
T
Yang
Shinya
S
Kasamatsu
Eiichi
E
Negishi
Guobao
G
Li
Jianhua
J
Lin
Hiroyuki
H
Nojiri
Takeshi
T
Rachi
Katsumi
K
Tanigaki
Naoki
N
Toyota