Massey products in symplectic manifolds

The paper is devoted to study of Massey products in symplectic manifolds. Theory of generalized and classical Massey products and a general construction of symplectic manifolds with nontrivial Massey products of arbitrary large order are exposed. The construction uses the symplectic blow-up and is based on the author results, which describe conditions under which the blow-up of a symplectic manifold X along its submanifold Y inherits nontrivial Massey products from X ot Y. This gives a general construction of nonformal symplectic manifolds.Comment: LaTeX, 48 pages, 2 figure

Phase transitions and exchange interactions in the SmCr3(BO3)4 crystal

© The Authors, published by EDP Sciences.Spectroscopic investigation and specific heat and magnetic susceptibility measurements of SmCr3(BO3)4 crystals were performed. The spectra of the Sm3+ and Cr3+ ions in samarium chromium borate were calculated and parameters of the exchange interactions between the nearest chromium ions, chromium and samarium ions were determined. Three phase transitions were observed at the temperatures T1= 7.8 ± 0.5 ?, T2 = 6.7 ± 0.5 ?, and T3 = 4.3 ± 0.2 ?, their nature is discussed. The crystal structures with different space symmetry groups R32 and C2/c were found to coexist in SmCr3(BO3)4 single crystal

Phase transitions and exchange interactions in the SmCr3(BO3)4 crystal

© The Authors, published by EDP Sciences. Spectroscopic investigation and specific heat and magnetic susceptibility measurements of SmCr 3 (BO 3 ) 4 crystals were performed. The spectra of the Sm 3+ and Cr 3+ ions in samarium chromium borate were calculated and parameters of the exchange interactions between the nearest chromium ions, chromium and samarium ions were determined. Three phase transitions were observed at the temperatures T1= 7.8 ± 0.5 ?, T 2 = 6.7 ± 0.5 ?, and T 3 = 4.3 ± 0.2 ?, their nature is discussed. The crystal structures with different space symmetry groups R32 and C2/c were found to coexist in SmCr 3 (BO 3 ) 4 single crystal