Interfacial Antiferromagnetic Coupling and Dual-Exchange Bias in Tetragonal SrRuO₃–PrMnO₃ Superlattices

Abstract

The functional properties of oxide heterostructures depend on the interfaces accommodating ions, their spins, and structural mismatches. Here, by stabilizing tetragonal symmetry, we achieve the in-plane antiferromagnetic (AFM) ordering and dual-exchange bias in the superlattices consisting of two ferromagnets SrRuO (SRO) and PrMnO (PMO). The tetragonal symmetry of this superlattice system achieved after the octahedral rotations yield an elongation of the c-axis parameter with Ru-O-Mn bond angle close to 180°, induces an interfacial antiferromagnetic ordering, which is suppressed as the ferromagnetic (FM) ordering in the PMO layer increases. The 0.1 T in-plane cooling field (H) leads to the shift (ca. -0.04 T) of minor hysteresis loop along the negative field axis due to the presence of -0.87 erg/cm AFM interfacial exchange coupling energy density (E) at 20 K. The exchange bias field (H) switches from negative to positive value with the increase in H. For 5 T H, the H is positive, but the E is -1.25 erg/cm for n ≤ 8 (n = number of unit cells of PMO) and 1.52 erg/cm for n ≥ 8. The H and its switching from negative to positive with the increase in H are explained by the interplay of strong antiferromagnetic coupling energy and Zeeman energy at the interfaces. The results demonstrate that the SRO-PMO superlattice could be a model system for the investigation of the interfacial exchange coupling in functional oxides.

Ultrathin Scale Tailoring of Anisotropic Magnetic Coupling and Anomalous Magnetoresistance in SrRuO3−PrMnO3 Superlattices

“…18 The superlattice period (Λ) of this series of superlattices calculated from the satellite peak positions obtained from the XRD patterns confirms the desired stacking fabrication of the superlattices. 18 The reciprocal space mappings (RSM) constructed from the Bragg's reflection measurements consisting of 2θ−ω coupling scans in (001) pc for n = 5 and (103) pc of various superlattices for different ω values are shown in Figure 1a,b, respectively. The RSM pattern of the superlattice with n = 5 shows the presence of (001) Bragg's reflection from STO along with the signature satellite fringes of the superlattice up to second order, which are symmetrically present on either side of the zeroth-order reflection, in both position and intensity.…”

“…The growth of highly oriented epitaxial [17 − uc (unit cell)SrRuO 3 /n(= 3, 4, ..., 12) − uc PrMnO 3 ] 15 /(001) SrTiO 3 (STO) has been reported elsewhere. 18 The out-of-plane X-ray diffraction (XRD) pattern and reciprocal space mapping were recorded by a four-cycle X-ray diffractometer. Atomic force microscopy (AFM) was employed to analyze the surface morphology and roughness.…”

Evidence of weak antilocalization in quantum interference effects of (001) oriented La0.7Sr0.3MnO3–SrRuO3 superlattices

“…The broadness of the satellite peaks is due to the merging of Kiessig fringes. 12 The simulated XRD profile included in Figs. 1(a) and 1(b) was obtained using the DIFFaX program, 12,13 which is in good agreement with the measured XRD with respect to the position of Bragg's peaks and their relative diffracted intensity.…”

“…12 The simulated XRD profile included in Figs. 1(a) and 1(b) was obtained using the DIFFaX program, 12,13 which is in good agreement with the measured XRD with respect to the position of Bragg's peaks and their relative diffracted intensity. The satellite peak positions obtained from the XRD patterns of the superlattice series are used to calculate the superlattice period (Λ).…”

Interfacial reconstruction in La0.7Sr0.3MnO3 thin films: giant low-field magnetoresistance

“…19 The synthesis of the LSMO lm on LAO introduced structural reconstruction of LSMO from a À b À c À type octahedral tilt to a 0 b 0 c À similar to PrMnO 3 /SrRuO 3 . 20 Interestingly, the tetragonal LSMO thin lm does not conserve the unit cell volume, in contrast to the LSMO lm on LAO with a conserved volume. 21 As shown in Fig.…”