Structural role in temperature-induced magnetization reversal revealedin distorted perovskite Gd1-xYxCrO3

The phenomenon of temperature induced magnetization-reversal, giving rise to negative magnetization (NM)in several rare-earth chromates, has been revisited through magnetization studies on Gd1-xYxCrO3. The studyre-examines the well accepted explanation of NM, i.e., the antiparallel polarization of the paramagnetic rare-earth(R3+) moments against the weak magnetization (MCr) of the canted antiferromagnetically ordered Cr3+momentsubsystem and compares the results with a relatively new explanation invoking frustration of the Gd3+momentsubsystem at temperatures as high as 170 K [Phys. Rev. B99, 014422 (2019)]. Keeping in view the highlylocalized nature of f electrons the invoked frustration appears unphysical. We find that the magnitude of theNM increases with increasing concentration of nonmagnetic Y3+ion. This is attributed to increased antiparallelpolarization of the Gd3+moments against increasedMCrdue to structural modifications in Gd1-xYxCrO3withincreasing Y3+content. This observation strongly contradicts the interpretation for NM based on the frustrationof Gd3+moments. The temperature induced negative to positive magnetization jump (TMJ) is observed and isattributed to the minimization of the Zeeman-energy against an energy barrier. A phenomenological comparativestudy of the modified Curie-Weiss fitting to M(T) indicates that TMJ in polycrystalline Gd1-xYxCrO3is anoutcome of cascaded individual flips of Gd3+moments occurring over random sites having homogeneouslydistributed barrier energy. In our analysis the M(T) data is fitted using modified Curie-Weiss treatingMCrto betemperature dependent, i.e.,MCr(T)=M(0).[1-(T/TC)alpha]beta