Role of Interlayer in 3D Vertically Aligned Nanocomposite Frameworks with Tunable Magnetotransport Properties

Abstract

Very recently, a 3D framework design integrating complex VAN structures has drawn great research interest. [2,6,21,22] The 3D framework is generated by integrating the multilayer and VAN designs together-numerous vertical nanopillars connect with the lateral interlayers to form a 3D interconnected frame embedded in the matrix. This 3D framework design combines the lateral and vertical strain engineering within the film, exhibits both advantages of the multilayer and VAN designs, and achieves an unprecedented degree of control of the film strain and properties. [6,22] The 3D framework thin films were first demonstrated in La 0.7 Sr 0.3 MnO 3 (LSMO)-CeO 2 systems by inserting one to three layers of CeO 2 (or LSMO) interlayers into the LSMO-CeO 2 VAN counterparts and forming 3D CeO 2 (or LSMO) frameworks. [6] Later, the feasibility of this 3D framework concept was demonstrated in LSMO-ZnO system along with a study on the effect of the ZnO interlayer thickness, which was controlled from 0 to ≈10 nm and effectively tuned the magnetotransport performance of the 3D framework films. [22] The overall framework (i.e., the secondary interlayers) embedded in all the reported 3D thin films is homogeneous, such as CeO 2 , LSMO, and ZnO. [6,21,22] Studies on heterogeneous interlayers are still rare. Moreover, the interlayer and its interplay with the matrix material are crucial for the 3D frameworks, since the 3D frames consist of vertical nanopillars and lateral interlayers.To achieve a precise control on the 3D framework structures, understanding the role of the interlayer within the 3D framework is significant and necessary.In this work, a set of 3D framework thin films have been processed by inserting different lateral interlayers (M). These interlayers present different in-plane matching distances from LSMO as illustrated in Figure 1a. The interlayer M candidates are yttria-stabilized zirconia (YSZ, 8 mol% Y 2 O 3 + 92 mol% ZrO 2 ), CeO 2 , SrTiO 3 (STO), BaTiO 3 (BTO), and MgO. In the resulting 3D structures, all ZnO nanopillars connect with the lateral interlayer M and create a 3D heterogeneous frame embedded in the LSMO matrix. The role of the lateral interlayer in determining the 3D heterogeneous framework microstructure and magnetotransport properties is systematically studied. The aforementioned interlayer materials are selected for the following reasons: 1) the in-plane lattice matching To investigate the role of interlayers on the growth, microstructure, and physical properties of 3D nanocomposite frameworks, a set of novel 3D vertically aligned nanocomposite (VAN) frameworks are assembled by a relatively thin interlayer (M) sandwiched by two consecutively grown La 0.7 Sr 0.3 MnO 3 (LSMO)-ZnO VANs layers. ZnO nanopillars from the two VAN layers and the interlayer (M) create a heterogeneous 3D frame embedded in the LSMO matrix. The interlayer (M) includes yttria-stabilized zirconia (YSZ), CeO 2 , SrTiO 3 , BaTiO 3 , and MgO with in-plane matching distances increasing from ≈3.63 to ≈4.21 Å, and expected in-plane stra...

Self‐Assembled Metal–Dielectric Hybrid Metamaterials in Vertically Aligned Nanocomposite Form with Tailorable Optical Properties and Coupled Multifunctionalities

“…As the enlarged ENZ region of shown in Figure 5f, the ENZ wavelength of the Au–BTO/STO/Au–BTO film (green line) is 817 nm, lower than that of the Au–BTO/MgO/Au–BTO film (red line) at 893 nm, indicating the lower dielectric permittivity and higher free‐electron density of the STO interlayered film. In the other studies of strain engineering in oxide–oxide VAN structures including LSMO–CeO 2 [ 61,74 ] and LSMO–ZnO, [ 75 ] the ML VAN films exhibit controllable electrical transport phenomena and magnetoresistance properties due to the enhanced strain‐engineering effects in the 3D framework.…”

Approaches to enhance low-field magnetoresistance effect at room temperature of self-assembled manganite nanocomposite films via microstructure design

“…With the thickness of ZnO inserting layer increased from 0 to ∼2 nm, the maximum LFMR value increased from ∼20% at 195 K to ∼31% at ∼132 K, which is a 50% enhancement over the VAN LSMO:ZnO films. 19 The LFMR effect at room temperature and above has also been realized by controlling microstructures. The LFMR value of 18.7% at 300 K has been observed in the VAN LSMO:NiO films, which is attributed to the fine microstructure, in which the unit structure period width defined as the two neighboring LSMO and NiO columns is only about 2.2 nm.…”

“…The tilted LSMO/ CeO 2 interfaces exhibit distinct domain mismatch patterns that are different from the vertical phase boundaries and thus present highly efficient strain tuning and highly improved magnetic and transport performances. The LSMO:CeO 2 film with the nanodumbbell structure exhibited the highest LFMR value of ∼22% at ∼334 K. 15 More recently, the LFMR results of 3D framework nanocomposite LSMO films have aroused great interest 15,[19][20][21][22] For example, in the 3D LSMO-framed nanocomposite LSMO:CeO 2 films, by changing the number of horizontal LSMO interlayer from one to three layers to form a 3D conducting LSMO framework, the LFMR peak temperatures have been tuned systematically from 325 to 310 K and the maximum LFMR value of 13% at 316 K has been obtained (Figure 3). 21 The MTJs of LSMO/CeO 2 /LSMO and their geometrical arrangement in these composite films play an important role for enhancing the LFMR properties.…”

ZnO-AuxCu1−x Alloy and ZnO-AuxAl1−x Alloy Vertically Aligned Nanocomposites for Low-Loss Plasmonic Metamaterials

“…Recently, great interest has arisen in oxide–metal vertically aligned nanocomposite (VAN) thin films for use as hyperbolic metamaterials [ 15 ]. VAN thin films are made up of two immiscible materials, co-deposited during a one-step self-assembly pulsed-laser deposition (PLD) technique [ 16 , 17 , 18 , 19 ]. The resultant morphology enables the formation of a matrix phase of one material embedded within the pillars of the second phase.…”