Abstract
The anisotropies of the EPR linewidth andg-factor were investigated in two-dimensional molecular composites of the type [NH3−R−NH3]MX4. Measurements were performed both in single crystals and powders over the temperature range 4.2–290 K. The spin-lattice relaxation timeT 1 was measured using the modulation method, as a function of temperature. The samples exhibit different structures and coupling interactions, according to the nature of the halogen X, the metal M and the organic radical R. We have analysed the influence of these parameters on spin behavior by studying the samples [NH3−(CH) n −NH3]MX4 with M=Mn, Cu; X=Cl, Br, andn=2, 3, 4, 5. When R is constituted by molecules with unsaturated bonds, these materials can be considered as excellent matrices for selective polymerisation reactions by irradiation or thermal processing. We have performed EPR measurements on the heated complex of propargylamine and cadmium chloride [HC∈C−CH2−NH3]2CdCl4. The obtained data are interpreted taking into account the strong exchange interaction and the various coupling interactions in the samples. The thermal dependences ofT 1 are explained by means of the Bloembergen and Wang three-reservoir model. The data whow spin diffusion when the metal is manganese, and an antisymmetric exchange interaction modulated by phonons in the case of copper. The nature of the halogen plays an important role in spin dynamics and namely in spin-lattice relaxation. The results obtained on [HC∈C−CH2−NH3]2CdCl4 after heating under vaccum show the creation of many paramagnetic centers due to the vanishing of triple bonds and the occurrence of a strong exchange interaction.
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References
Kubo R., Tomita K.: J. Phys. Soc. Japan9, 888–920 (1954)
Négrier P., Chanh N.B., Courseille C., Hauw C., Meresse A., Couzi M.: phys. stat. solidi (a)100, 473–483 (1987)
Buisco V., Carfagna C., Salerno V., Vacatello M., Fittipaldi F.: Solar Energy24, 575 (1980)
Tieke B., Chapuis G.: Crystalloraphical Ordered Polymers, ACS Symposium Series (Sandman, ed.),337, chap. 5, pp. 61–77, 1987.
Willet R.D.: Acta. Cryst. B33, 1651 (1977)
Tichy K., Benes J., Kind R., Arend H.: Acta. Cryst. B36, 1355–1367 (1980)
Khechoubi M.: Thése. Université de Bordeaux 1 1993.
Hervé J., Pescia J.: C. R. Acad. Sciences Paris251, 665–667 (1960)
Pescia J.: Ann. Phys. (Paris)10, 389–407 (1965)
Ablart G., Pescia J.: Phys. Rev. B22, 1150–1162 (1980)
Cheung T.T.P., Soos Z.G.: J. Chem. Phys.69 (8), 3845–3853 (1978)
Soos Z.G., McGregor K.T., Cheung T.T.P., Silverstein A.J.: Phys. Rev. B16, 3036–3047 (1978)
Bloembergen N., Wang S.: Phys. Rev.92, 72–84 (1954)
Richards P.M., Salamon M.B.: Phys. Rev. B9, 32–45 (1974)
Giordano M., Martinelli M., Pardi L., Santucci S.: phys. stat. solidi (b),84, 305–310 (1977)
Bourdel D., Ablart G., Pescia J., Clement S., Renard J.P.: Phys. Rev. B23, 1339–1341 (1981)
Bourdeau-Lartigue C.: Thése. Université C.: Thése. Universitédde Bordeaux I 1994.
Seehra M.S., Castner T.G.: J. Phys. Kondens. Materie7, 185 (1968)
Huber D.L., Seehra M.S.: J. Phys. Chem. Solids36, 723 (1975)
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Invited lecture at the 27th Congress AMPERE, Kazan, August 22–27, 1994.
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Niang, A., Ablart, G., Pescia, J. et al. Electron paramagnetic resonance and spin-lattice relaxation in two-dimensional systems. Appl. Magn. Reson. 8, 319–333 (1995). https://doi.org/10.1007/BF03162794
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DOI: https://doi.org/10.1007/BF03162794