Effect of External Factors on Magnetism of Fluctuating Low-Dimensional Electron and Spin Correlations in Frustrated Manganites La.sub.1 - .sub.ySm.sub.yMnO.sub.3 + [delta]

The effect of external factors on the temperature dependences of the magnetization of frustrated manganites La.sub.1 - .sub.ySm.sub.yMnO.sub.3 + [delta] ([delta] ~ 0.1, y = 0.85, 1.0) is studied. Two sharp peaks M(T) of different intensities detected in both samples at close temperatures Т.sub.1 and Т.sub.2 slightly higher than the critical temperature T.sub.c of the coherent superconducting transition corresponds to the Lindhard divergence [chi].sub.L(q.sub.nest) of the temperature dependence of the paramagnetic susceptibility of stripelike 1D electron/spin correlations modulated with wave vectors q.sub.nest1 = 2k.sub.F1 and q.sub.nest2 = 2k.sub.F2. The formation and evolution of magnetization features with increasing field are explained by the appearance of spatial modulation of electrical and magnetic properties in ab planes in the case of total nesting of electron-hole areas of the Fermi surface. This appears as two fragments of two fluctuating quasi-one-dimensional charge/spin density waves with wave vector q.sub.1 || a and q.sub.2 || b directions incommensurate with the lattice. It is assumed that the strong dependence of the magnetization of fluctuating 1D charge/spin density wave correlations on external influences is caused by the immediate vicinity of sample properties to the quantum critical point.