Role of initial heat treatment of the ferrite component on magnetic properties in the composite of ferrimagnetic Co1.75Fe1.25O4 ferrite and non-magnetic BaTiO3 oxide

Vacancy-induced interfacial ferromagnetic features in SmFeO3-filled graphitic carbon foam

“…Magnetization analyses of CFM type 1 (A) and CFM type 2 (B-D) revealing the presence of a significant magnetic transition in both the type of samples at approximately 150 K. In D the large values of the measured saturation magnetization are attributable to the presence of residual a-Fe within the CFM type 2 sample.The transition 1 at about 140 K in CFM type-1 sample appears to be due to Fe 3 O 4 (high ferrimagnetic phase) with Verwey transition expected in a wide temperature range 120-140 K 29,30. However, XRD measurements do not support the presence of such iron oxide phase in the present samples.9880 | RSC Adv., 2020, 10, 9878-9883 This journal is © The Royal Society of Chemistry 2020 RSC Advances Paper Open Access Article.…”

“…Note the presence of 4 peak features which may be attributable to (1) SmFeO 3 magnetic moments (feature 1), (2) p-electrons of the CFM, (3) defect induced ferromagnetic-components and (4) antiferromagnetic transition occurring in some portion of the encapsulated SmFeO 3 phase due to enhanced contribution of Sm magnetic moments. Note that no additional iron oxide phases were detected in the XRD and Rietveld refinement analyses 29. ESR spectra at 77 K acquired from CFM type 1, turbostratic graphite powder and water doped turbostratic graphite powder.…”

Existence of two spin dynamics in the temperature and magnetic field dependence of the magnetization curves of ferrimagnetic Co1.75Fe1.25O4 and its composite with BaTiO3

“…In this work, we demonstrate the effects of intrinsic magnetic disorder in ferrimagnetic Co 1.75 Fe 1.25 O 4 spinel oxide [21] and extrinsic magnetic disorder in its composite with nonmagnetic BaTiO 3 [22]. The intrinsic spin disorder in the spinel oxide is expected due to replacement of a fraction of the Fe 3+ (high spin state) ions at B sites by the non-magnetic (low spin) Co 3+ ions and random exchange of the remaining magnetic ions (Co 2+ (highly anisotropic) and Fe 3+ (less anisotropic)) between A and B sites.…”

“…The material preparation and characterization of the Co 1.75 Fe 1.25 O 4 (CFO) ferrite and its composite with BaTiO 3 (BTO) were described in earlier works [21][22]. The as prepared ferrite powder after chemical reaction was made into pellet and thermally annealed at different temperatures (200-1100 0 C) for 2 hrs.…”

“…Interestingly, structural phase instability of the Co 1.75 Fe 1. 25 O 4 ferrite has been reduced in its composite with BaTiO 3 (ferroelectric and non-magnetic) [22].…”