Magic hole doped composition of 152Sm1-xSrxMnO3 manganite:: crystal structure and unusual magnetic properties in paramagnetic phase at x=0.45

Neutron diffraction investigations and data on second harmonic of magnetization are presented for (Sm0.55Sr0.45MnO3)-Sm-152 manganite. The coherent Jahn-Teller distortions are found to occur just below 300 K, collapse at T-C similar to 125 K, and exhibit a rather complicated temperature behavior between these points. Temperature dependence of a spontaneous magnetization evidences the first-order transition at TC and a homogeneous ferromagnetic phase below T-C with practically full ferromagnetic alignment at T similar to 1.5 K. A field hysteresis of the second harmonic is observed above T-C that is associated with the CE-type antiferromagnetic regions possessing a weak ferromagnetism, as well as with the ferromagnetic domains. Interconnection of spin and Jahn-Teller phonons degrees of freedom is supposed to account for the inhomogeneous paramagnetic phase with the nontrivial properties., (C) 2002 Elsevier Science B.V. All rights reserved.