Magnetic Sponge Phenomena Associated with Interchain Dipole鈥揇ipole Interactions in a Series of Ferrimagnetic Chain Compounds Doped with Minor Diamagnetic Species

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• 作者：Masaki Nishio ; Hitoshi Miyasaka
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：May 5, 2014
• 年：2014
• 卷：53
• 期：9
• 页码：4716-4723
• 全文大小：536K
• 年卷期：v.53,no.9(May 5, 2014)
• ISSN：1520-510X

文摘

The donor/acceptor ionic chain (i.e., the D⁺A^{鈥?/sup> chain) [Ru₂(2-MeO-4-ClPhCO₂)₄(BTDA-TCNQ)]路2.5(benzene) (1; 2-MeO-4-ClPhCO₂鈥?/sup> = 2-methoxy-4-chlorobenzoate; BTDA-TCNQ = bis(1,2,5-thiadiazolo)tetracyanoquinodimethane) is a ferrimagnetic chain with S = 3/2 from [Ru₂II,III]+ (i.e., D+) and S = 1/2 from BTDA-TCNQ鈥⑩€?/sup> (i.e., A鈥?/sup>), with J 鈮?鈭?00 K, in which long-range antiferromagnetic ordering at T_N = 11 K occurs because interchain antiferromagnetic interactions are critical. Compound 1 undergoes a reversible crystal-to-crystal structural transformation with the elimination/absorption of the crystallization solvent to form the dried compound [Ru₂(2-MeO-4-ClPhCO₂)₄(BTDA-TCNQ)] (1鈥?, which has a higher T_N (14 K). This change is clearly caused by the shortening of the interchain distances because the exchange coupling parameter for the chain is the same in both 1 and 1鈥? The chain compounds in 1 can be doped with minor diamagnetic [Rh₂II,II] species, [{(Ru₂)_1鈥?i>x(Rh₂)_x(2-MeO-4-ClPhCO₂)₄}(BTDA-TCNQ)]路2.5(benzene) (x = 0.03 for Rh-3%; x = 0.05 for Rh-5%; x = 0.16 for Rh-16%), which shifts the T_N to lower temperatures, the magnitude of the shift being dependent on the doping ratio x (T_N = 5.9 K for Rh-3%, T_N = 3.7 K for Rh-5%, and T_N was not observed above 1.8 K for Rh-16%). Drying a doped compound increased its T_N, as was found for 1鈥? T_N = 9.9 K for Rh-3%鈥? T_N = 9.2 K for Rh-5%鈥? and T_N was not observed above 1.8 K for Rh-16%鈥? T_N had a linear relationship with the doping ratio x of the [Rh₂] species in both the fresh and dried compounds. The T_N linear relationship is associated with the magnitude of the effective magnetic dipole (i.e., the average correlation length) in the chains caused by the [Rh₂] defects as well as naturally generated defects in the synthetic process and with the interchain distances affected by the crystal-to-crystal transformations. These results demonstrate that slightly modifying the short-range correlation lengths, which changes the magnetic dipole magnitudes, strongly affects the bulk antiferromagnetic transition, with key dipole鈥揹ipole interactions, in low-dimensional anisotropic systems.}