arXiv:cond-mat/0610464v1 [cond-mat.str-el] 17 Oct 2006 Inhomogeneous phase separation and domain wall dynamics in the orthorhombically distorted La 0.87 MnO x K. De, S. Majumdar, S. Giri Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India E-mail: sspsg2@iacs.res.in (S Giri) Abstract. We observe the interesting magnetization and resistivity results in the orthorhombically distorted self doped manganite, La 0.87 MnO x . A significant irreversibility between zero-field-cooled and field-cooled resistivities as well as magnetization data is clearly observed up to a temperature which is well above the both paramagnetic to ferromagnetic (T c ) and metal to insulator transition (T MI ) temperatures. In the ferromagnetically ordered and metallic states the magnetotransport results suggest the influence of domain wall dynamics. Interesting scenario of memory effects through the domain wall dynamics is strikingly observed in the relaxation of resistivity in a limited temperature region. The characteristic features of magnetotransport behaviour are suggested duo to the co-existence of structurally driven inhomogeneous phase separation and domain wall dynamics. PACS numbers: 75.47.Lx, 72.20.-i, 75.50.Lk