Phase diagram of compressively strained nickelate thin films

Abstract

The complex phase diagrams of strongly correlated oxides arise from the coupling between physical and electronic structure. This can lead to a renormalization of the phase boundaries when considering thin films rather than bulk crystals due to reduced dimensionality and epitaxial strain. The well-established bulk RNiO3 phase diagram shows a systematic dependence between the metal-insulator transition and the perovskite A-site rare-earth ion, R. Here, we explore the equivalent phase diagram for nickelate thin films under compressive epitaxial strain. We determine the metal-insulator phase diagram for the solid solution of Nd1-yLayNiO3 thin films within the range 0 ≤ y ≤ 1. We find qualitative similarity between the films and their bulk analogs, but with an overall renormalization in the metal-insulator transition to lower temperature. A combination of x-ray diffraction measurements and soft x-ray absorption spectroscopy indicates that the renormalization is due to increased Ni–O bond hybridization for coherently strained thin films.

Electrical resistivity anomaly in (Pr1−yMy)1−xCaxCoO3 epitaxial films (M=Y, Gd) fabricated by pulsed laser deposition

“…For example, in the RNiO 3 thin film, which shows the bandwidth controlled MI transition, the transition temperature, T MI , was increased (decreased) by tensile (compressive) in-plane strain. 20 The strain effect is attributed to an increase (decrease) of the Ni-O-Ni bond angle, which affects to films in the same way as the bulk under higher pressure. 21 Thin films of these materials have potential for various applications such as the use in resistive switches and phase-change memory.…”

Effect of strain on ferroelectric field effect in strongly correlated oxide Sm0.5Nd0.5NiO3

“…22,23 Significant modifications to their phase transition characteristics and T MI can be achieved by applying hydrostatic pressure, 22,23 imposing epitaxial strain, 19,[24][25][26][27][28] or varying internal chemical pressure via R-site cation substitution. 29,30 In particular, SNNO is close to the structural phase boundary where the T MI is about to decouple from the AFM Neel temperature and the MIT evolves from first-order to second-order, and thus exhibits high susceptibility to the structural modifications. Figure 2(a) shows R ٗ (T) upon warming for a 4 nm SNNO on LAO for both polarization states.…”

Tailoring the electronic transitions of NdNiO3 films through (111)pc oriented interfaces

“…Both (001) pc -and (111) pc -oriented NNO films grown on top of LSAT and LAO (Figures 2(a) and 2(c)) display a sharp MIT at, respectively, T MI = 170 K and T MI = 100 K. Consistently with previously reported results, the MIT occurs with a visible hysteresis at a critical temperature T MI lower than in bulk (T MI -bulk is indicated by the dashed line in Figure 2) and T MI decreases as the compressive strain increases. 20,22,24,29 The transport characterization of NNO/NGO (Figure 2(b)), however, reveals striking differences depending on the substrate orientation. (001) pc NNO/NGO undergoes a 1st order MIT at about 160 K, a behavior rather similar to that of NNO/LAO and NNO/LSAT films.…”

“…[15][16][17][18] In its bulk form, NNO undergoes a first order metal-to-insulator transition (MIT) that occurs along with a paramagnetic (PM) to antiferromagnetic (AFM) Néel transition at T MI = T Néel = 200 K. The AFM ground state is identified by the Bragg vector q Bragg = ( 1 /4 1 /4 1 /4) in pseudocubic (pc) notation. 16,17,19 By applying different levels of epitaxial strain on (001) pc oriented films, the occurrence of the MI and Néel transitions can be tuned over a wide temperature range, [20][21][22][23][24][25] the two transitions always occurring simultaneously, i.e., T MI = T Néel . A recent work revealed that NNO films, grown along other crystallographic axes on top of orthorhombic NdGaO 3 , display a MIT at exceptionally high temperature.…”