Intrinsic exchange bias inZnxMn3−xO4

Abstract

Bulk specimens of the hetaerolite solid solution ZnxMn3−xO4 with x = 0, 0.25, 0.5, 0.75, and 1 have been prepared as homogeneous, phase-pure polycrystalline samples as ascertained by neutron diffraction measurements. Samples with x = 0.25, 0.5, and 0.75 exhibit shifted magnetic hysteresis loops at low temperature, characteristic of exchange bias typically seen in magnetic composites. We propose that the unusual magnetic behavior arises as a result of a nanoscale mixture of ferrimagnetic and antiferromagnetic regions that are distinct but lack long-range order. While some glassy behavior is seen in AC magnetic measurements, its magnitude is not sufficient to account for the observed dramatic exchange bias. Furthermore, isothermal and thermoremanent magnetization measurements distinguish this material from a pure spin glass. The title system offers insights into the alloying of a ferrimagnet Mn3O4 with an antiferromagnet ZnMn2O4 wherein distinct magnetic clusters grow and percolate to produce a smooth transition between competing orders. PACS numbers:arXiv:0906.3534v2 [cond-mat.mtrl-sci]

Nanoscale Iron Nitride, ε-Fe3N: Preparation from Liquid Ammonia and Magnetic Properties

“…45,46 The present results indicate that the shifting of the hysteresis loops in both the pristine and oxidized samples are likely driven by mixed exchange interactions in the Fe-N caused by disorder at the nanoparticle surfaces.…”

Exchange bias effect in alloys and compounds

“…The EB effect has been investigated in bulk specimens of the solid solution, Zn x Mn 3−x O 4 with x = 0, 0.25, 0.5, 0.75 and 1 where structural phase-purity of the polycrystalline samples was ascertained by neutron-diffraction measurements [195].…”

Exchange bias effect in polycrystalline NiO/NiMn2O4 composite

“…This suggests that the area of the AFM/FIM interfaces increases with NiO concentration. Similar behavior was already observed in Zn x Mn 3Àx O 4 solid solutions [19]. The values of the coercive field were calculated by H C = (H C1 À H C2 )/2 and the values of the exchange field by H E = (H C1 + H C2 )/2, where H C1 and H C2 are the left and right coercive fields, respectively [20].…”