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HoCrO3, a member of the rare-earth chromate family, is known to exhibit an orthorhombic structure with Pbnm space group in bulk at room temperature. We have employed the pressure driven powder consolidation technique, spark plasma sintering, for synthesizing HoCrO3 powder-compact, which exhibits a superior quality with fewer defects over that synthesized by conventional solid-state sintering (resulting in a large reduction of charge carrier mediated extrinsic dielectric contribution). The powder compact shows magneto-dielectric coupling but does not exhibit a detectable ferroelectric phase in the range of 50 K to 300 K. Low temperature Raman spectra show structural distortions below 250 cm−1, indicating Ho ion displacements. Temperature evolution of the crystal structure using synchrotron x-ray diffraction reveals a probable structural phase transition below 240 K. Pyrocurrent measurement, together with synchrotron x-ray diffraction analysis, further points to a magneto-structural transition at 100 K. [ABSTRACT FROM AUTHOR]

We report on the angular and field dependence of the magnetoresistance (MR) in bilayers of Pt / EuO 1 − x thin films, measured in both in-plane and out-of-plane geometries at different temperatures (T). The presence of oxygen vacancies manifested by a metal–insulator transition as well as a high-T ferromagnet-to-paramagnet transition (TP) was observed in the bilayers. The anisotropic magnetoresistance could be extracted in the entire T-range, even above TP, exhibiting two sign crossovers. We attribute its T-evolution to the rotation of the easy axis of the magnetization direction from a high-T out-of-plane to a low-T in-plane orientation. In addition, we provide direct experimental evidence of the spin Hall effect-induced spin Hall magnetoresistance, systematically considering several known MR contributions that can arise from the films' (111) texture and interface. [ABSTRACT FROM AUTHOR]

Negative differential resistance (NDR) in current-voltage (I-V) characteristics and apparent colossal electroresistance were observed in Gd0.5Sr0.5MnO3 single crystals at low temperatures. The continuous dc I-V measurements showed a marked thermal drift. In addition, temperature of the sample surface was found to be significantly higher than that of the base at high applied currents. Two different strategies namely estimation and diminution of the Joule heating (pulsed I-V measurements) were employed to investigate its role in the electric transport properties. Our experiments reveal that the NDR in Gd0.5Sr0.5MnO3 is a consequence of Joule heating rather than the melting of charge order. [ABSTRACT FROM AUTHOR]

Interlayer magneto-electric coupling in BiFeO3/SrRuO3 heterostructures was investigated by impedance spectroscopy over a temperature range of 80 K-260 K. In-plane impedance measurements were performed using interdigitated gold electrodes fabricated on the BiFeO3 layer. The Nyquist plots at different temperatures were fitted with an equivalent circuit model of the heterostructure. A pronounced dip in the temperature coefficient of equivalent-capacitance and a distinct increase in the temperature coefficient of equivalent-resistance of the BiFeO3 layer were observed on cooling across ferromagnetic TC of the bottom SrRuO3 layer. Temperature dependent capacitance (at 0 T magnetic fields) and magneto-capacitance (at 5 T magnetic fields) plots showed anomalies near 160 K. A shift of the hysteresis loop along the magnetization axis in field cooled M-H measurements was also found, which indicates the presence of pinned SrRuO3 moments due to the magnetic interaction at the interface. These observations suggest a strong magneto-electric coupling between the BiFeO3 and SrRuO3 layers of this heterostructure. [ABSTRACT FROM AUTHOR]