Magnetization jumps and exchange bias induced by a partially disordered antiferromagnetic state in (FeTiO3)0.9-(Fe2O3)0.1

Abstract

Magnetization jumps (MJs) and the exchange bias (EB) effect are simultaneously observed in the mixed-spin oxide (FeTiO3)0.9-(Fe2O3)0.1 at 2.0 K. Dc and ac susceptibility measurements confirm a reentrant spin glass phase with a partially disordered antiferromagnetic (PDA) state below the irreversibility temperature (Tir = 60 K). Antiferromagnetic (AFM) Fe3+ clusters are nested in AFM Fe2+ lattices forming a triangular lattice, in which 2/3 of the magnetic moments order antiferromagnetically with each other leaving the remaining 1/3 “confused.” This geometric frustration in the triangular lattice leads to a PDA state that is the ground state of the AFM triangular configuration. The PDA state, in the presence of a critical trigger field, evolves into a ferromagnetic (FM) state, and induces the AFM spins of the Fe2+ ions to enter a FM state, resulting in the MJs. Meanwhile, the FM spins of Fe2+ can serve as the pinned phase, and the AFM spins of Fe3+ can serve as the pinning phase, resulting in the EB effect. Thus, we point out that the PDA state is very likely to be at the origin of the MJs and the EB effect.

Effects of R -site compositions on the meta-magnetic behavior of Tb 1 – x Pr x (Fe 0.4 Co 0.6 ) 1.88

“…Among them, doped CeFe 2 compounds exhibit intriguing magnetization jumps across the antiferromagnetic (AFM) to ferromagnetic (FM) transition, which shows characteristics resembling those in the martensitic scenario. [1,2] A similar jump behavior has been reported in many kinds of materials, such as intermetallic germanide Gd 5 Ge 4 , [3,4] mixed-valent manganite Pr 0.6 Ca 0.4 MnO 3 , [3,5,6] multiferroic Y 2 CoMnO 6 , [7] cubic NaZn 13 -type polycrystalline Pr 0.2 La 0.8 Fe 11.4 Al 1.6 , [8] mixed-spin oxide FeTiO 3 -Fe 2 O 3 , [9,10] and some other materials. [11,12] Among the family of the cubic C15 MgCu 2type Laves phase compounds RFe 2 (R = rare earth), Ouyang et al studied the mixing effects of light and heavy rare earths in Nd 1−x Tb x Co 2 .…”

Jahn–Taller distortion on exchange interactions between cations in Mn x Cu1−x Co2O4 system

“…Here, ∆T P represents the change of T P . When x ⩽ 0.5, the calculated Ω value is less than 0.08, which can be defined as a spin-glass behavior [43,44]. The figure 6(c) shows dominated interactions in the Mn x Cu 1−x Co 2 O 4 samples.…”

Magnetization Curves of Geometrically Frustrated Exchange-Biased FM/AFM Bilayers

“…These effects are widely studied theoretically and experimentally in layered FM/AFM systems but still have no comprehensive explanation. Despite a large number of works, the influence of the geometrical frustration in the bilayer system on the exchange bias has been little studied yet [2], [3]. The geometrical frustration appears when the minimum of the system energy does not correspond the minimum of all local interactions.…”