Single-Crystal Polarized Optical Absorption Spectroscopy of the One-Dimensional Ferrimagnet MnIICuII(pba)(H2O)3·2H2O (pba = 1,3-Propylenebis
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- 作者：Olivier Cador ; Corine Mathoniè ; re ; and Olivier Kahn
- 刊名：Inorganic Chemistry
- 出版年：2000
- 出版时间：August 21, 2000
- 年：2000
- 卷：39
- 期：17
- 页码：3799 - 3804
- 全文大小：90K
- 年卷期：v.39,no.17(August 21, 2000)
- ISSN：1520-510X
文摘
Powder and single-crystal optical absorption of the ferrimagnet MnIICuII(pba)(H2O)3·2H2O (denoted MnCu) andthe Mn-doped compound Mn0.1Mg0.9Cu(pba)(H2O)3·2H2O (denoted Mn0.1Mg0.9Cu) with pba standing for 1,3-propylenebis(oxamato) was investigated in the 10-300 K range. The crystal structure of MnCu was previouslyreported, and consists of bimetallic chains with octahedral MnII and square pyramidal CuII ions linked by oxamatobridges, MnCu and Mn0.1Mg0.9Cu being isostructural. The spectra of both MnCu and Mn0.1Mg0.9Cu show animportant dichroism along the chain direction, due to the strong polarization of the CuII band at around 16 000cm-1 in this direction. They exhibit narrow and intense spin-forbidden MnII transitions in the 24000-25000cm-1 range, which are activated by an exchange mechanism. The polarization and thermal dependence of the6A1g 
4A1g, 4Eg(G) MnII transitions were recorded. The polarization along the chain axis was interpreted in theframework of the pair mechanism first introduced by Tanabe and co-workers. A theoretical expression for thethermal dependence of the intensity was derived by considering the CuII spin as a quantum spin and the MnII spinas a classical spin, and compared with the experimental data. The interaction parameter between the local groundstates has been found to be J = -25 cm-1 using the spin Hamiltonian H = -J
i(SMn,isCu,i + SMn,i+1sCu,i). Thespectra of Mn0.1Mg0.9Cu showed cold and hot bands, whose energy difference is directly related to J and theinteraction parameter J* between the CuII ion in its ground state and the MnII ion in its spin-flip excited state. J*has been estimated to be +40 cm-1. These results have been compared to those obtained with other MnIICuIIcompounds. The complementarity between optical and magnetic properties has been discussed.
4A1g, 4Eg(G) MnII transitions were recorded. The polarization along the chain axis was interpreted in theframework of the pair mechanism first introduced by Tanabe and co-workers. A theoretical expression for thethermal dependence of the intensity was derived by considering the CuII spin as a quantum spin and the MnII spinas a classical spin, and compared with the experimental data. The interaction parameter between the local groundstates has been found to be J = -25 cm-1 using the spin Hamiltonian H = -Ji(SMn,isCu,i + SMn,i+1sCu,i). Thespectra of Mn0.1Mg0.9Cu showed cold and hot bands, whose energy difference is directly related to J and theinteraction parameter J* between the CuII ion in its ground state and the MnII ion in its spin-flip excited state. J*has been estimated to be +40 cm-1. These results have been compared to those obtained with other MnIICuIIcompounds. The complementarity between optical and magnetic properties has been discussed.