Modeling temperature dependent exchange bias in systems with magnetoelectric chromia

Abstract

Exchange bias in a magnetoelectric Cr2O3/ferromagnet system at finite temperature, based on the formation of a domain wall in Cr2O3, has been investigated using Monte Carlo simulation. It has been shown that the calculation of the exchange bias based on domain wall formation yields a more realistic value than that calculated using interfacial exchange coupling between Cr2O3 and the adjacent ferromagnet. Possible shortcoming of the magnetoelectric effect in setting the switchable exchange bias in the low temperature regime has also been demonstrated based on an energy threshold requirement. Specifically, it has been found that the magnetoelectric effect becomes intrinsically less effective in switching the exchange bias at low temperature, thus making the applicability of the system limited to only a certain temperature range.

Large perpendicular exchange bias and high blocking temperature in Al-doped Cr2O3/Co thin film systems

“…In addition, recently, a reasonable J K (H ex ) has been estimated for a Cr 2 O 3 =FM system by Monte Carlo simulation. 10) Moreover, from the results of the domain wall width calculation of Cr 2 O 3 17) (∼60 nm when K AF ∼ 10 5 erg=cm 3 ), we can estimate the AFM domain wall energy of ∼0.6 erg=cm 2 , which is in good agreement with the low-temperature experimental J K values (∼0.5 erg=cm 2 ) of Cr 2 O 3 =Co thin film systems. From these results, we believe that Mauri's model must be taken into account in considering the exchange bias in the Cr 2 O 3 =Co system, while further development of the model is required for the quantitative discussion of T B and the explanation of the abrupt variations in H ex and H c at T B .…”

“…Recently, in a Cr 2 O 3 =ferromagnet (FM) system, experimental H ex values have been approximately reproduced on the basis of Mauri's model. 10) Mauri's model might explain the exchange bias of the Cr 2 O 3 =FM system; however, further validations are necessary.…”