Four isomorphous phosphates AM3P4O14 (A = Sr, Ba; M = Co, Mn) with antiferromagnetic-antiferromagnetic-ferromagnetic trimerized chains, showing 1/3 quantum magnetization plateaus only in the manganese(II) system.
The four new phosphates BaCo3P4O14 (1), SrCo3P4O14 (2), BaMn3P4O14 (3), and SrMn3P4O14 (4) were hydrothermally synthesized and characterized structurally and magnetically. They are isostructural with ANi3P4O14 (A = Ca, Sr, Pb, Ba), crystallizing in the monoclinic space group P2(1)/c. The CoO6 (or MnO6) octahedra share edges to from zigzag chains along the b axis, which are further interconnected by P2O7 groups into a three-dimensional structure. Preliminary magnetic measurements on powder samples indicate that 1, 2, and 4 are spin-canted antiferromagnets and 3 is a pure antiferromagnet at low field; long-range orderings were established respectively at T critical approximately 8.2 K for 1, 6.5 K for 2, and 2.6 K for both 3 and 4; field-induced spin-flop-like transitions occur respectively at Hc approximately 25 kOe for 1, 4 kOe for 2, 3 kOe for 3, and 0.7 kOe for 4. Interestingly, together with the known Ni analogues, they all apply the same antiferromagnetic-antiferromagnetic-ferromagnetic (AAF) trimerized chain model, whereas the 1/3 quantum magnetization plateau only appears in the Mn system. By qualitative analysis, we conclude that the appearance of quantum magnetization plateaus in the AAF chain compounds requires both good 1D characteristics and strong AF intrachain interactions.
Yang
Tao
T
Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People's Republic of China.
Zhang
Yan
Y
Yang
Sihai
S
Li
Guobao
G
Xiong
Ming
M
Liao
Fuhui
F
Lin
Jianhua
J