Magic hole doped composition of 152Sm 1− xSr xMnO 3 manganite: crystal structure and unusual magnetic properties in paramagnetic phase at x=0.45

Abstract

Neutron diffraction investigations and data on second harmonic of magnetization are presented for 152Sm 0.55Sr 0.45MnO 3 manganite. The coherent Jahn–Teller distortions are found to occur just below 300 K, collapse at T C∼125 K, and exhibit a rather complicated temperature behavior between these points. Temperature dependence of a spontaneous magnetization evidences the first-order transition at T C and a homogeneous ferromagnetic phase below T C with practically full ferromagnetic alignment at T∼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.