Effect of External Factors on Magnetism of Fluctuating Low-Dimensional Electron and Spin Correlations in Frustrated Manganites La1 – ySmyMnO3 + δ (y = 0.85, 1.0)

Resumo

The effect of external factors on the temperature dependences of the magnetization of frustrated manganites La_1 – ySm_yMnO_3 + δ (δ ~ 0.1, y = 0.85, 1.0) is studied. Two sharp peaks M(T) of different intensities detected in both samples at close temperatures Т₁ and Т₂ slightly higher than the critical temperature T_c of the coherent superconducting transition corresponds to the Lindhard divergence χ_L(q_nest) of the temperature dependence of the paramagnetic susceptibility of stripelike 1D electron/spin correlations modulated with wave vectors q_nest1 = 2k_F1 and q_nest2 = 2k_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 q₁ || a and q₂ || 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.