Regeneration of perpendicular exchange-biased state in high temperature regime in Pt/Co/Au/Cr₂O₃/Pt stacked films

Abstract

Exchange bias (EB) has been a hot research topic since its discovery in the 1950s. In this paper, we present the peculiar temperature dependence of perpendicular EB in Pt/Co/Au/Cr 2 O 3 /Pt stacked films: the regeneration of the EB in the high temperature regime. Three temperature-dependent states are identified: (1) low temperature exchange-biased state, (2) middle temperature coercivity-enhanced state, and (3) high temperature regenerated exchange-biased state. At the boundary of these states, both EB field (H EB ) and coercivity (H C ) abruptly switch with the relationship H EB = ΔH C . The low temperature disappearance of EB can be interpreted based on the classical Meiklejohn-Bean exchange anisotropy model. A more complex temperature dependence of the interfacial spin alignment and magnetic domain wall width in the Cr 2 O 3 layer is involved in the high temperature regeneration of EB. © 2020 The Japan Society of Applied Physics 3. Results and discussions 3.1. Epitaxial growth Typical sets of RHEED images are shown in Fig. 2. The RHEED patterns of the Pt buffer surface and the Cr 2 O 3 surface appear streaky, indicating the smooth surface of these layers. The diffraction patterns suggest the growth of Pt(111) and Cr 2 O 3 (0001). The 〈1120〉 substrate -azimuthal RHEED patterns for Pt(111) and Cr 2 O 3 (0001) [Fig. 2(b)] are both

Magnetoelectric control of antiferromagnetic domain state in Cr2O3 thin film

“…In the case of the FM/Cr 2 O 3 stacked film, this enhancement can be suppressed by using a suitable spacer layer such as Au at the FM/Cr 2 O 3 interface [59]. Based on this investigation, it was also inferred that the spin-frustration at the twin boundary was a possible cause for the high J K [57], and the hightemperature regeneration of the perpendicular exchange bias was also reported as another effect of the spin frustration [50][51][52][53][54][55][56][57][58][59][60][61]. The details about this exchange bias can be found in the reviews [30][31][32] and, those about the perpendicular exchange bias using the Cr 2 O 3 (0001) film, in particular, can be found in review [55].…”

Structural, Magnetic, and Electric Properties of Pt/Co/Au/Cr₂O₃/Pt Thin Film with Cr₂O₃ Layer below 25 nm

“…The exchange bias abruptly disappeared at 102 K, and the coercivity was enhanced, accompanied with a disappearance of the exchange bias. This abrupt disappearance was observed for the FM/Cr2O3(0001) stacked film 13,18) and is likely to be a unique feature of this system. Details on this unique temperature dependence can be found in our previous review 19) .…”

“…For the case of Cr2O3(0001) thin film, the DW width along the caxis was calculated in the range of 20-70 nm depending on the lattice parameter 11) . Recently, ME-induced switching of the perpendicular exchange bias was demonstrated using 30-nm-thick Cr2O3(0001) thin film 12) , and perpendicular exchange bias using a Cr2O3(0001) layer was confirmed for film with 20-nm-thick Cr2O3 13) ; for both cases, the Cr2O3 thickness was near the DW width. In this paper, we explored the possibility of the perpendicular exchange bias persisting below the 20-nmthick Cr2O3(0001) layer as well as the electric properties that are also important for electric field application.…”