Signatures of electronic phase separation in the Hall effect of anisotropically strained La_0.67Ca_0.33MnO₃films

Abstract

Systematic transport measurements have been performed on a series of La 0.67 Ca 0.33 MnO 3 thin films with varying degrees of anisotropic strain. The strain is induced via epitaxial growth on NdGaO 3 (001) substrates and varied by controlling the thermal annealing time. An antiferromagnetic insulating (AFI) state, possibly associated with charge ordering, emerges upon thermal annealing. The Hall effect in these materials exhibits features that are indicative of a percolative phase transition and correlate closely with the emergence of the AFI state. In the paramagnetic phase, the Hall resistivity takes on two slopes in all samples: a decreasing negative slope with increasing temperature at low fields, which is attributed to the carrier hopping motion, and an almost temperature independent positive slope at high fields due to diffusive transport of holes. Significantly, the crossover fields of the Hall resistivity slope at different temperatures correspond to the same magnetization, which is interpreted as

Exploring the Metal–Insulator Transition in (Ga,Mn)As by Molecular Absorption

“…The strikingly large Hall resistivity variation disappears at higher temperatures in this insulating sample. The percolation feature is similar to the observed thresholds of percolative MIT effect. , This behavior occurs at low temperature after n-type molecular doping, which provides another evidence that the film changes from a metallic phase to an insulating phase.…”

Spin correlations and colossal magnetoresistance inHgCr2Se4

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Buffer electrode layers tuned electrical properties, fatigue behavior and phase transition of KNN-based lead-free ferroelectric films

“…The conductive type of buffer electrode layers has been proven by previous works. 29–32 Our results demonstrate that the conductive type of the buffer electrode layer can effectively tune the electrical properties, fatigue behavior and phase transition of KNNLT-M ferroelectric films. The p-type electrode buffered KNNLT-M films exhibit more saturated hysteresis loops, larger twice remnant polarization and higher dielectric constant compare to the n-type electrode buffered films.…”