From magnetic cluster glass state to giant vertical magnetization shift induced by ferromagnetic cluster growth in SrFe0.25Co0.75O2.63

Abstract

A charge ordering phenomenon within the crystallographic sites as following Sr4(Fe0.143+Co0.363+)48h(Fe0.114+Co0.144+Co0.253+)48fO10.52 was previously reported thanks to neutron diffraction coupled with Mossbauer spectroscopy studies. Such distribution supports a natural magnetic layered structure combining both in-plane ferromagnetic super-exchange interactions mainly on the octahedron “8 f” sub-layer alternating and in-plane antiferromagnetic super-exchange interactions on the “8 h” sub-layer containing tetrahedral sites and five-fold symmetry polyhedra (i.e. squared based pyramid and/or trigonal bipyramid). Because of the interfacial magnetic interactions between the two types of layers, we report a detailed study of the intriguing magnetic properties. AC magnetic susceptibility shows a frequency dependent peak suggesting a cooperative character due to inter-cluster interactions resulting in a magnetic cluster glass state. When temperature decreases and/or applied magnetic field increase, the ferromagnetic clusters growth is promoted and results in a large vertical hysteretic shift on the Field Cooled magnetization isotherm in relation with minor loop.