Strain-Induced Anisotropic Transport Properties of LaBaCo₂O_5.5+δ Thin Films on NdGaO₃ Substrates

Abstract

Thin films of double-perovskite structural LaBaCo2O5.5+δ were epitaxially grown on (110) NdGaO3 substrates by pulsed laser deposition. Microstructural studies by high-resolution X-ray diffraction and transmission electron microscopy revealed that the films have an excellent quality epitaxial structure. In addition, strong in-plane anisotropic strains were measured. Electrical transport properties of the films were characterized by an ultra-high-vacuum four-probe scanning tunneling microscopy system at different temperatures. It was found that the anisotropic in-plane strain can significantly tune the values of film resistance up to 590%.

Anisotropic Strain Induced Directional Metallicity in Highly Epitaxial LaBaCo2O5.5+δ Thin Films on (110) NdGaO3

“…From the Fig. 1(b), it is clearly see that the resistivity of LBCO is lowered down by adjusting the growth oxygen pressure, but the resistivity of [100] direction is smaller than that of [010] direction, which is opposite to the previous report14. In order to understand the underlying mechanism, reciprocal-space maps (RSMs) are recorded around the (001), (013), and (103) reflections of the LBCO films (Fig.…”

“…Except the sensitivity to oxygen content, the physical properties of LBCO thin film are highly dependent on the type and amplitude of interface strain. It has been demonstrated that the isotropic interface strain induced by different cubic structure substrate improve colossal magnetoresistance of LBCO by 5 times of bulk material13, and the anisotropic interface strain (compressive strain along [100] and tensile strain along [010] relative to LBCO bulk material) induced by orthorhombic (110) NdGaO 3 (NGO) substrate with the lattice parameters a  = 5.433 Å, b  = 5.503 Å, and c  = 7.715 Å generate a stable and larger anisotropic resistivity in a wide temperature range from 300 K to 130 K14. Compared to the interface strain induced by different cubic substrate, the anisotropic interface strain generated by orthorhombic (110) NGO substrate with different in-plane lattice parameters (7.733 Å along the direction and 7.715 Å along [001] direction) can effectively exclude the influence of different growth modes and crystalline quality on different samples, since there is only variation for the sample on (110) NGO substrate.…”

“…Based on the previous study of LBCO thin film14, we plan to tune and optimize its properties by adjusting the growth oxygen pressure and temperature, which play a crucial role in determining the physical properties and structure of thin film. It is found that the increased growth oxygen pressure and temperature low down the resistivity of LBCO thin film, but the lattice constant of LBCO thin film is enlarged and an metal-insulator transition directionally occurs, namely, it only takes place in one of the in-plane directions, and in the other direction, the film maintains its semiconducting behavior.…”

Gas Sensing Properties of Epitaxial LaBaCo2O5.5+δ Thin Films

“…To under these physics nature, single crystalline LBCO thin films are required. Recently, highly epitaxial single crystalline LBCO thin films were fabricated on various substrates, such as (001) LaAlO 3 (LAO)16, (001) SrTiO 3 171819, (001) MgO2021, and (110) NdGaO 3 22. The LBCO films not only exhibit a much larger magnetoresistance value than those from various phases of its bulk material, but also possess an extraordinary sensitivity to H 2 and O 2 , especially an exceedingly fast redox reaction at high temperature and a superfast oxygen vacancy exchange diffusion chemical dynamics1623.…”

Magnetically correlated anisotropic resistive switching manipulated by electric field in Co/PMN-PT heterostructures

“…Several work have introduced the strain mediated variations of magnetic properties [6-8, 10, 12-16], electronic transport [17][18][19][20], Verway transition [21] and even spin-orbital coupling [22] in magnetoelectric heterostructures. The electric-field-controlled reversible magnetization rotation, which is important for practical applications in a wide range of low-power magnetic and spintronic devices [1,12], has been reported in Ni/0.7Pb(Mg 1/3 Nb 2/3 )O 3 -0.3PbTiO 3 [8,10,23] (Ni/PMN-PT) and CoFeB/PMN-PT [24] as well as the phase field simulations [8,12].…”