Negative magnetization and exchange bias effect in Fe-doped CoCr2O4

Negative zero‐field‐cooled magnetization and magnetic switching in multiferroic Lu0.5Sc0.5FeO3 ceramics

“…Meanwhile, the value of negative magnetization at 10 K gradually increases with the increase of applied magnetic field. When the applied magnetic field reaches up to 3 kOe, the magnetization changes from negative to positive, similar to that in CoCr 2 O 4 49 and YMn 0.5 Cr 0.5 O 3 . 50 It can be concluded that the negative magnetization in LSFO is related to a technical magnetization in the process as like YMn 0.5 Cr 0.5 O 3 , such as rotation or movement of magnetic domains or pinning of the domain wall, rather than the spontaneous magnetization behavior.…”

“…Because the negative value of magnetization only appears in the ZFC curve as shown in Figure 1B, it can be considered that a small negative magnetic field, trapped in the superconducting magnet, results in negative magnetization in LSFO similar to the researches of negative magnetization revealed in the ZFC curve in CoCr 2 O 4 and YMn 0.5 Cr 0.5 O 3 . 49,50 For the superconducting magnet in PPMS without equipping with the low-field option to reduce the remnant field, a small field with a few Oersteds always exists when setting the field to zero from a high initial field, which is trapped from the magnetic flux inside the superconducting material. 49 When the previous posi-tive magnetic field returns to zero, a negative trapped field (NTF) is generated, and conversely, a positive trapped field (PTF) is generated.…”

“…49,50 For the superconducting magnet in PPMS without equipping with the low-field option to reduce the remnant field, a small field with a few Oersteds always exists when setting the field to zero from a high initial field, which is trapped from the magnetic flux inside the superconducting material. 49 When the previous posi-tive magnetic field returns to zero, a negative trapped field (NTF) is generated, and conversely, a positive trapped field (PTF) is generated. In general, the trapped field is negative because the field was reduced from a positive value.…”

Mg-Doped CoCr2O4 Nanoparticles: Implications for Magnetic Memory and Magnetocaloric Effect

“…However, for x ≥ 0.20, no FIM transition was observed, except for samples with x = 0.20 and 0.30 that exhibited a glassy magnetic phase due to intense AFM interaction. Li et al conducted a temperature-dependent magnetization investigation on Co­(Cr 1– x Fe x ) 2 O 4 ( x = 0–0.12) ceramics and found that the T C increases with Fe concentration while the T S decreased, indicating the replacement of Cr 3+ ions by Fe 3+ ions. Kamran et al reported on ZFC and FC magnetization investigations of Mg-doped CoCr 2 O 4 NPs with composition x = 0 to 1.…”

“…Notably, unlike the bulk counterparts, no magnetic transition from short-range FIM order to the long-range spiral spin structure was observed at low temperatures for NPs with a diameter ( D ) of ≤5.4 nm, instead indicating a transition to a cluster spin-glass (SG) state. Although limited literature is available on the magnetic properties of cobalt chromite NPs, promising results have been obtained by doping the A- and B-sites with various ions such as Cu, Cd, Ni, Fe, Mg, and Mn, illustrating the significant influence of dopants on magnetic properties. ,,− However, the magnetocaloric effect, spin glass structure, and memory effect of doped CoCr 2 O 4 NPs have not been extensively explored. Moreover, prior investigations have demonstrated that Mg doping enhances the magnetic memory and magnetocaloric effect compared to the pristine compound.…”