Magnetic Properties of Tetra-Transition-Metal Substituted Weakley-Type Germanotungstates

作者：Zhao Junwei; Ma Pengtao; Wang Jingping; Niu Jingyang^*

来源：Journal of Cluster Science, 2009, 20(4): 671-681.

DOI：10.1007/s10876-009-0270-5

• Magnetic properties
• Polyoxometalate
• Sandwich structure
• Weakley-type

Magnetic susceptibility investigations have been carried out on a family of the tetra-transition-metal sandwiched Weakley-type germanotungstates Na(11)H[Co(4)(H(2)O)(2)(alpha-GeW(9)O(34))(2)]center dot 31H(2)O (1), (C(6)N(2)H(18))(4)[Co(H(2)O)(6)]H(2)[Co(4)(H(2)O)(2)(alpha-GeW(9)O(34))(2)]center dot 5.5H(2)O (2) and Na(H(2)O)(2)(C(6)N(2)H(18))(4.75)H(1.5)[Ni(4)(H(2)O)(2)(alpha-GeW(9)O(34))(2)]center dot 1.5H(2)O (3) with the intention of studying the magnetic exchange properties of the rhomb-like four transition-metal ions in the central belt. The Co-Co and Ni-Ni ferromagnetic exchange interactions are dominant in the rhomb-like M(4)O(16) units in 1-3. Furthermore, magnetic susceptibility measurements also reveal that the magnetic coupling constant J is a sensitive parameter that is closely realted to the M-O-M angles and M center dot center dot center dot M separations in the rhomb-like magnetic core. Variable-temperature ac susceptibilities exhibit that magnetic properties of 2 and 3 are related to the spin glassy behaviors.

• 出版日期2009-12
• 单位河南大学