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Author Mączka, Mirosław ♦ Gągor, Anna ♦ Hermanowicz, Krzysztof ♦ Sieradzki, Adam ♦ Macalik, Lucyna ♦ Pikul, Adam
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ CATIONS ♦ CHEMICAL ANALYSIS ♦ CHEMICAL COMPOSITION ♦ CHROMIUM ♦ DOPED MATERIALS ♦ ELECTRON SPIN RESONANCE ♦ FERROELECTRIC MATERIALS ♦ FERROMAGNETISM ♦ FORMATES ♦ MAGNETIC SUSCEPTIBILITY ♦ MAGNETIZATION ♦ MONOCRYSTALS ♦ ORGANOMETALLIC COMPOUNDS ♦ PEROVSKITE ♦ PHASE TRANSFORMATIONS ♦ PHONONS ♦ TRANSITION TEMPERATURE ♦ X RADIATION ♦ X-RAY DIFFRACTION
Abstract We have incorporated Cr(III) into [(CH{sub 3}){sub 2}NH{sub 2}][Mn(HCOO){sub 3}] (DMMn) multiferroic metal organic framework (MOF). The highest concentration of Cr(III) in the synthesized samples reached 15.9 mol%. The obtained samples were characterized by powder and single-crystal X-ray diffraction, DSC, magnetic susceptibility, dielectric, EPR, Raman and IR methods. These methods and the performed chemical analysis revealed that electrical charge neutrality after substitution of Cr(III) for Mn(II) is maintained by partial replacement of dimethylammonium (DMA{sup +}) cations by neutral HCOOH molecules. These changes in the chemical composition are responsible for weakening of the hydrogen bonds and decreased flexibility of the framework. This in turn leads to lowering of the ferroelectric phase transition temperature, observed around 185 K for undoped DMMn and around 155 K for the sample containing 3.1 mol% of Cr(III), and lack of macroscopic phase transition for the samples with Cr(III) content of 8.2 and 15.9 mol %. Another interesting effect observed for the studied samples is pronounced strengthening of the weak ferromagnetism of in Cr(III)-doped samples, associated with slight decrease of the ferromagnetic ordering temperature from 8.5 K for DMMn to 7.0 K for the sample with 15.9 mol % Cr(III) content. - Graphical abstract: Incorporation of Cr(III) into [(CH3)2NH2[Mn(HCOO)3] framework increases the magnetization. - Highlights: • Chromium(III) substitutes for Mn(II) in the studied MOF. • Charge neutrality is maintained by replacing DMA{sup +} cations by neutral HCOOH molecules. • Compounds with 8.2 and 15.9% of Cr(III) show no phase transition above 100 K. • Doping with Cr(III) increases magnetization.
ISSN 00224596
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-05-15
Publisher Place United States
Journal Journal of Solid State Chemistry
Volume Number 237


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