Spin switching and unusual exchange bias in the single-crystalline GdCrO3 compensated ferrimagnet

An unusual exchange bias (EB) effect in single-crystalline GdCrO3 compensated ferrimagnet (fM), composed of two antiferromagnetically coupled Gd and Cr sublattices, presenting two opposite ferromagnetic (FM) moments, is reported. It is shown that the temperature- or field-induced fast reversal of the net FM moment in GdCrO3 may be identified as a switching between two opposite spin configurations, attendant with abrupt drop in Zeeman energy ≈kB(7×10−4K) per formula unit. It was found that the FM moment reversal is exchange biased in the narrow temperature interval above the compensation temperature Tcomp=144K. Namely, the EB field emerges and diverges upon approaching Tcomp at temperatures T>Tcomp while unexpectedly it collapses to zero below Tcomp. This is in contrast to experimental results obtained for compensated fMs RFeO3(R=Nd, Sm, Er) orthoferrites showing EB in a narrow range, both above and below Tcomp. We suppose that breakdown of EB in GdCrO3 may be linked to the lack of anisotropy of the spin-only Gd S-ion magnetic moment dominating below Tcomp.