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. (August 2021)

• Record Type: Journal Article
• Authors: Bhowmik, R.N.; Ranganathan, R.
• Is Part Of: Journal of physics and chemistry of solids. Volume 155(2021)
• Publication Date: 2021-08
• Subjects: Spinel ferrite -- BaTiO3 -- Composite magnet -- Exchange bias -- Memory and aging effect; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2021.110103
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: The present work describes ferrimagnetic properties of spinel oxide Co1.75 Fe1.25 O4 (CFO) and its composite (CFO_BTO) with ferroelectric and non-magnetic BaTiO3 (BTO). Rietveld refinement of the synchrotron X-ray diffraction patterns provided detailed structural phase information of the CFO and CFO_BTO samples. The dc magnetization measurements confirmed blocking temperature of the samples around 300 K for applied magnetic field 500 Oe and exchange bias effect at 5 K. On the other hand, both the samples exhibited a strong magnetic memory effect at around 250 K and the memory effect gradually suppressed at low temperatures. Apart from conventional modifications of magnetic moment and coercivity in composite system with reference to pure spinel ferrite system, the present work has shown that ferrimagnetic parameters can be varied by adopting some unconventional measurement protocols, where time dependent magnetization has been recorded during measurements of the temperature and field dependent magnetization curves. The analysis of waiting time dependent magnetization data confirmed the existence of two non-equilibrium spin dynamics, defined by different time constants, both in CFO ferrite and CFO_BTO composite systems. The measurements also confirmed the dilution of magnetic exchange interaction and faster spin relaxation in the composite system. Highlights: Two non-equilibrium spin dynamics in ferrimagnetic spinel oxide and it's composite. Structural refinement performed for structural and magnetic information. Tuning of magnetic state and coercivity by controlling non-equilibrium spin dynamics. Application of double exponential function for confirming two relaxation contributions. Exhibition of the magnetization blocking, magnetic exchange bias and memory effects.